Change from 4-speed to 3w/OD

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Cool wagon. You are right, these Tx. drivers will run over ya ***!!! BUT thy all drive trucks with the loudest most obnoxious exhaust system anywhere in America!!! ha

I had a 67 cuda 383 2.94 4 speed car. ( NO od!!) No tack.... when I picked it up in Ca, and drove it back to MO. so I do not know the rpm is was running. I ran it 75 down the interstates, got 18 mpg with TQ and those 2.94 gears. Even with that torque 383 it was not like I wanted taking off. I was used to always having a 3.55 with my stick cars. I do not remember the tire size. I have had many 4 speed cars, a few 4spd OD cars, and truck.. I much more enjoy banging the gears in a 4 speed. but I just remind myself if I have the OD it is NOT like banging the 4 speed trans.... Guy came by my house right after I got home and bought it so I never got to mess with that car....
I would look at a taller tire, a 3:23 gear and drive it and not worry so much about rpm if me... If you go the 833OD just remind yourself of all the tech gear ratios you are told of here. It is a different duck.
 
I love this stuff
To be doing 70@3000 requires 3.55s and tires 27.8 tall.I skimmed some of the posts and may have missed your saying this; no matter, math is math, and it doesn't work out with 3.23 or 3.7s so I'm good with 3.55s.
Ok so if you install the od-box (that's what I call it), with no other changes, the cruise Rs come down to .73x3000=2190rpm/2660@85
And that would be fine for a 360 with a cam of about 220/225, or less.That size of cam is out of reversion just about there,(maybe as low as 2000) and all the air in the intake is finally going in the same and right direction, so you can tune the cruise-circuit lean, for mpgs.By the time you get to a 250*cam it's hopeless at 2200. Even my 367/230*cam, which cruises at 2250, get's terrible fuel mileage.
And a 360 with a 220/225 cam makes gobs and gobs of torque to pull those splits. It won't be a racecar, but with your wagon, Ima thinking that's OK.
Bottom line is if you have a low-rpm 360 like with a 220* or less cam, it will pull that od-Box just fine. If you have a high-rpm 360 like a 250* cam, I wouldn't go back there. Between 225 and 245, it's kindof whatever you're willing to put up with.
_______________________________________________________________________
Ok so, here's a brief description of my thoughts, experiences and opinions.
Lets look at the ratios;
your current box which hopefully is the 2.66-1.91-1.39-1.00 which has splits of .72-.73-.72 and that's pretty sweet. Whatever RPM you shift at, the R's will fall to those %s in the following gear. Example: shifting at 5500,the Rs will drop to 3990ish. So to satisfy that,your engine needs a powerband of 1512rpm.
And the odBox, is 3.09-1.67-1.00-.73 with splits of .54-.60-.73. Again shifting at 5500, the Rs will drop to 2970 and 3300, making a powerband requirement of 2530/2200.This,by itself is not a big deal in a lightweight car with a torquey 360, unless you want hi-performance.
So let's install them, and look at the overall gearing, with those 3.55s.
Currently..... 9.44-6.78-4.93-3.55
odBox........ 10.97-5.93-3.55-2.59
Notice third gear. This is a loss of 28%TM (torque multiplication). The only way to get it back is with 28% more rear gear..........Which totally relegates first gear to being useless; (4.93x3.09=15.23).As well the od gear becomes 3.60,lol
Ok but. line 'em up like this;
...........9.44-6.78-4.93-3.55
....10.97............5.93....3.55-2.59
Now you can see how it really compares. The odBox gets you a deep low, then a gear between Second and Third, plus the delicate OD gear that even a 3184bbl blows up, if you're not careful. Ok so look at that. Imagine your 360 plowing thru those gears with the new TM. If you get the idea that I'm not a fan of that box and a high revver, you would be right. I tried it with several different rears and was never happy.For my engine, Second gear was just too far away. So what to do.
Well, I got me a 3.09Low Commando trans (C-Box) and converted it to a slip yoke, and changed the rear gear. It could look like this in your car; with no od.
std box 2.66x3.55 9.44-6.78-4.93-3.55 ..the current combo........................ 70=3000
C-Box 3.09x3.23s 9.98-6.20-4.49-3.23 %change .... +5.7,-8.6,-8.9,-9.0 and 70=2730
C-Box 3.09x2.94s 9.08-5.64-4.07-2.94 %change to std -3.1-16.8-17.4-17.2; 70=2480
The splits are still all the same, so the only places I actually noticed the wonkyness was on the slightly higher 1-2 shift, and it stays in each gear to a slightly higher roadspeed, which translates to slightly lower performance, but not near as bad as the od box.
I tried the 2.66 box and 2.94s but I found the 7.71 starter too lame for a 292/508cam, and I didn't much like it with a 223* cam either. That's when I bought the GVOD and started splitting those wide gears, some right up the middle; 3.09-2.41-1.67-1.30-1.00-.78/.73-.54

And I gotta warn you; I blew three of those boxes up. My winter 3184bbl shredded one od gear, and my regular 360 also shredded one. But the 360 also shredded all the teeth of the input gear, of a third box, leaving me with a nice clutch line-up tool. So if you need parts,lol............. I tell ya it ain't easy trying to remember to ease it into that od-Fourth!
 
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AJ/FormS said:
I love this stuff
To be doing 70@3000 requires 3.55s and tires 27.8 tall.I skimmed some of the posts and may have missed your saying this; no matter, math is math, and it doesn't work out with 3.23 or 3.7s so I'm good with 3.55s.
Ok so if you install the od-box (that's what I call it), with no other changes, the cruise Rs come down to .73x3000=2190rpm/2660@85
And that would be fine for a 360 with a cam of about 220/225, or less.That size of cam is out of reversion just about there,(maybe as low as 2000) and all the air in the intake is finally going in the same and right direction, so you can tune the cruise-circuit lean, for mpgs.By the time you get to a 250*cam it's hopeless at 2200. Even my 367/230*cam, which cruises at 2250, get's terrible fuel mileage.
And a 360 with a 220/225 cam makes gobs and gobs of torque to pull those splits. It won't be a racecar, but with your wagon, Ima thinking that's OK.
Bottom line is if you have a low-rpm 360 like with a 220* or less cam, it will pull that od-Box just fine. If you have a high-rpm 360 like a 250* cam, I wouldn't go back there. Between 225 and 245, it's kindof whatever you're willing to put up with.
_______________________________________________________________________
Ok so, here's a brief description of my thoughts, experiences and opinions.
Lets look at the ratios;
your current box which hopefully is the 2.66-1.91-1.39-1.00 which has splits of .72-.73-.72 and that's pretty sweet. Whatever RPM you shift at, the R's will fall to those %s in the following gear. Example: shifting at 5500,the Rs will drop to 3990ish. So to satisfy that,your engine needs a powerband of 1512rpm.
And the odBox, is 3.09-1.67-1.00-.73 with splits of .54-.60-.73. Again shifting at 5500, the Rs will drop to 2970 and 3300, making a powerband requirement of 2530/2200.This,by itself is not a big deal in a lightweight car with a torquey 360, unless you want hi-performance.
So let's install them, and look at the overall gearing, with those 3.55s.
Currently..... 9.44-6.78-4.93-3.55
odBox........ 10.97-5.93-3.55-2.59
Notice third gear. This is a loss of 28%TM (torque multiplication). The only way to get it back is with 28% more rear gear..........Which totally relegates first gear to being useless; (4.93x3.09=15.23).
Ok but. line 'em up like this;
...........9.44-6.78-4.93-3.55
...10.97............5.93....3.55-2.59
Now you can see how it really compares. The odBox gets you a deep low, then a gear between Second and Third, plus the delicate OD gear that even a 3184bbl blows up, if you're not careful. Ok so look at that. Imagine your 360 plowing thru those gears with the new TM. If you get the idea that I'm not a fan of that box and a high revver, you would be right. I tried it with several different rears and was never happy.For my engine, Second gear was just too far away. So what to do.
Well, I got me a 3.09Low Commando trans (C-Box) and converted it to a slip yoke, and changed the rear gear. It could look like this in your car; with no od.
std box 2.66x3.55 9.44-6.78-4.93-3.55 the current combo
C-Box 3.09x3.23s 9.98-6.20-4.49-3.23 % difference +5.7- 8.6,-8.9-9.0 and 70=2730
C-Box 3.09x2.94s 9.08-5.64-4.07-2.94 % from current-3.1-16.8-17.4-17.2; 70=2480
The splits are still all the same, so the only places I actually noticed the wonkyness was on the slightly different 1-2 shift, and it stays in each gear to a slightly higher roadspeed, which translates to slightly lower performance, but not near as bad as the od box.
I tried the 2.66 box and 2.94s but I found the 7.71 starter too lame for a 292/508cam, and I didn't much like it with a 230* cam either. That's when I bought the GVOD and started splitting those wide gears, some right up the middle; 3.09-2.41-1.67-1.30-1.00-.78/.73-.54

And I gotta warn you; I blew three of those boxes up. My winter 3184bbl shredded one od gear. and my regular 360 also shredded one od gear. But it also shredded all the teeth of the input gear, of a third box, leaving me with a nice clutch line-up tool. So if you need parts,lol............. I tell ya it ain't easy trying to remember to ease it into that od-Fourth!
Click to expand...
this is what i ment in my first post!!! AJ knows his gearing!
 
AJ/FormS said:
I love this stuff
To be doing 70@3000 requires 3.55s and tires 27.8 tall.I skimmed some of the posts and may have missed your saying this; no matter, math is math, and it doesn't work out with 3.23 or 3.7s so I'm good with 3.55s.
Ok so if you install the od-box (that's what I call it), with no other changes, the cruise Rs come down to .73x3000=2190rpm/2660@85
And that would be fine for a 360 with a cam of about 220/225, or less.That size of cam is out of reversion just about there,(maybe as low as 2000) and all the air in the intake is finally going in the same and right direction, so you can tune the cruise-circuit lean, for mpgs.By the time you get to a 250*cam it's hopeless at 2200. Even my 367/230*cam, which cruises at 2250, get's terrible fuel mileage.
And a 360 with a 220/225 cam makes gobs and gobs of torque to pull those splits. It won't be a racecar, but with your wagon, Ima thinking that's OK.
Bottom line is if you have a low-rpm 360 like with a 220* or less cam, it will pull that od-Box just fine. If you have a high-rpm 360 like a 250* cam, I wouldn't go back there. Between 225 and 245, it's kindof whatever you're willing to put up with.
_______________________________________________________________________
Ok so, here's a brief description of my thoughts, experiences and opinions.
Lets look at the ratios;
your current box which hopefully is the 2.66-1.91-1.39-1.00 which has splits of .72-.73-.72 and that's pretty sweet. Whatever RPM you shift at, the R's will fall to those %s in the following gear. Example: shifting at 5500,the Rs will drop to 3990ish. So to satisfy that,your engine needs a powerband of 1512rpm.
And the odBox, is 3.09-1.67-1.00-.73 with splits of .54-.60-.73. Again shifting at 5500, the Rs will drop to 2970 and 3300, making a powerband requirement of 2530/2200.This,by itself is not a big deal in a lightweight car with a torquey 360, unless you want hi-performance.
So let's install them, and look at the overall gearing, with those 3.55s.
Currently..... 9.44-6.78-4.93-3.55
odBox........ 10.97-5.93-3.55-2.59
Notice third gear. This is a loss of 28%TM (torque multiplication). The only way to get it back is with 28% more rear gear..........Which totally relegates first gear to being useless; (4.93x3.09=15.23).
Ok but. line 'em up like this;
...........9.44-6.78-4.93-3.55
...10.97............5.93....3.55-2.59
Now you can see how it really compares. The odBox gets you a deep low, then a gear between Second and Third, plus the delicate OD gear that even a 3184bbl blows up, if you're not careful. Ok so look at that. Imagine your 360 plowing thru those gears with the new TM. If you get the idea that I'm not a fan of that box and a high revver, you would be right. I tried it with several different rears and was never happy.For my engine, Second gear was just too far away. So what to do.
Well, I got me a 3.09Low Commando trans (C-Box) and converted it to a slip yoke, and changed the rear gear. It could look like this in your car; with no od.
std box 2.66x3.55 9.44-6.78-4.93-3.55 the current combo.......................... 70=3000
C-Box 3.09x3.23s 9.98-6.20-4.49-3.23 %change to std+5.7- 8.6,-8.9-9.0 and 70=2730
C-Box 3.09x2.94s 9.08-5.64-4.07-2.94 %change to std -3.1-16.8-17.4-17.2; 70=2480
The splits are still all the same, so the only places I actually noticed the wonkyness was on the slightly different 1-2 shift, and it stays in each gear to a slightly higher roadspeed, which translates to slightly lower performance, but not near as bad as the od box.
I tried the 2.66 box and 2.94s but I found the 7.71 starter too lame for a 292/508cam, and I didn't much like it with a 223* cam either. That's when I bought the GVOD and started splitting those wide gears, some right up the middle; 3.09-2.41-1.67-1.30-1.00-.78/.73-.54

And I gotta warn you; I blew three of those boxes up. My winter 3184bbl shredded one od gear. and my regular 360 also shredded one. But the 360 also shredded all the teeth of the input gear, of a third box, leaving me with a nice clutch line-up tool. So if you need parts,lol............. I tell ya it ain't easy trying to remember to ease it into that od-Fourth!
Click to expand...


Unbelievable amount of information. Thanks!
 
Sounds like a early 833 with low 1st gear and a aftermarket overdrive would work well. (or a late model 5 speed)
 
IMG_0243.jpg
 
toolmanmike said:
Sounds like a early 833 with low 1st gear and a aftermarket overdrive would work well. (or a late model 5 speed)
Click to expand...
You got it Mike!
3.09-1.92-1.40-1.00-.78GVOD is the combo I now use with 3.55s. For me it's the perfect combo.The starter gear is 10.97, equivalent to 4.10s with the 2.66box, about as low as you need to go on the street.I tried lower and higher, and settled on the 3.55s,cuz
The slightly wider 1-2 split is perfect for getting moving.The other splits are factory.
I shift 1,2 3, 3od, and finally 4od for a little tighter 3-4 split. If you care, that's
3.09-1.92-1.40-1.09-.78od.. I occasionally think about an aftermarket box, but those I couldn't split-shift.
 
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I'll throw my 2 cents worth in here because I kind of have these combos.
My 70 Challenger with 3.23 and a 225/70R14 rear tire runs 3300 @ 70-75 mph.
My 68 Charger with 3.23 gear and a 4 speed od out of a pu truck with 275/60R15 runs low to mid 2k @75 mph. Gets mid teen, mpg from a 440, all making it a pure joy on the highway.
You don't have to worry about the torque capacity of the od gear, because the countershaft is seeing the same torque load in every gear except 3rd which is direct, input and main shaft locked together. The overdrive actually removes torque from the mainshaft to the tires. Just as first gear multiplies the torque by 3.09 the over drive is multiplying by .72, so the theory that 300lbft can't be shoved through overdrive does not hold water.
The aluminum case is torque limited but I would not afraid of any of the iron case ones.
I have to go with RRR on the speeds. My transmission in my big truck is a 15 speed, I do not use them all, all the time but they all count. The high gear (5th) in each range is a overdrive (less than 1:1) but they all count and the 15 speed is represented in the model number of the transmission.
My 2 cents FWIW.
 
I have 2 iron 833od, one in my 64 dart, I have 355 limit slip 83/4 stock wheels and a built 340 pushing it .
1st gear is a waste and only gets me to 30ish, if I try to power shift it into second the wheels break loose, but it is really hard to shift it into second. Forget about down shifting into 1st it just wont do it. revs are pretty low in overdrive but it lugs if I am going under 40.

Bottom line is it is OK for just cruising around but if you want to have more fun consider something else.
I have purchased a regular 833 and am going to swap it out as soon as I get all of the parts I need, and time to do it.
 
70bigblockdodge said:
I'll throw my 2 cents worth in here because I kind of have these combos.
My 70 Challenger with 3.23 and a 225/70R14 rear tire runs 3300 @ 70-75 mph.
My 68 Charger with 3.23 gear and a 4 speed od out of a pu truck with 275/60R15 runs low to mid 2k @75 mph. Gets mid teen, mpg from a 440, all making it a pure joy on the highway.
You don't have to worry about the torque capacity of the od gear, because the countershaft is seeing the same torque load in every gear except 3rd which is direct, input and main shaft locked together. The overdrive actually removes torque from the mainshaft to the tires. Just as first gear multiplies the torque by 3.09 the over drive is multiplying by .72, so the theory that 300lbft can't be shoved through overdrive does not hold water.
The aluminum case is torque limited but I would not afraid of any of the iron case ones.
I have to go with RRR on the speeds. My transmission in my big truck is a 15 speed, I do not use them all, all the time but they all count. The high gear (5th) in each range is a overdrive (less than 1:1) but they all count and the 15 speed is represented in the model number of the transmission.
My 2 cents FWIW.
Click to expand...
a RTO-15 has a od of .74...RTO-13 got a od of .87....a RTOO-13 got od of .87 in 11th .71 in 12th and 13th is .68 whoop whoop truck'in up!!
 
I used to re-build those RoadRangers for a living. And others too. Prettyeasychit actually. That mightabin the very early 80s, about the time the 15 speeds started showing up. Wait, I remember. It was when the Mack trucks came out with RoadRangers rated at around 1200ftlbs, IIRC.
I really enjoyed that kindof work.
 
AJ/FormS said:
I used to re-build those RoadRangers for a living. And others too. Prettyeasychit actually. That mightabin the very early 80s, about the time the 15 speeds started showing up. Wait, I remember. It was when the Mack trucks came out with RoadRangers rated at around 1200ftlbs, IIRC.
I really enjoyed that kindof work.
Click to expand...
grew up working on dad an g'pa's big trucks, what i lernt on, wrench'in and driving! been in a few,..rebuilt 13 speed back boxes few times...but far from expert!! really better at driving than wrenchin on them! takes skills to speed shift a rto 12.5-13!!! makes shifting a 833 a walk in a park!!
 
dirty white boy said:
grew up working on dad an g'pa's big trucks, what i lernt on, wrench'in and driving! been in a few,..rebuilt 13 speed back boxes few times...but far from expert!! really better at driving than wrenchin on them! takes skills to speed shift a rto 12.5-13!!! makes shifting a 833 a walk in a park!!
Click to expand...
The shift pattern on this 15 spd will mess me up for the first few miles when I jump in my Charger. Comes back quickly though.
The OD are a little different the drop from first to second is big. Downshifting to first you have to match the RPM to road speed to get it in smoothly.
Mine really lugs at 50 mph I just put it back in 3rd /direct.
The A833 OD is not the best choice for street and strip, but makes a great cruiser.
 
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dirty white boy said:
grew up working on dad an g'pa's big trucks, what i lernt on, wrench'in and driving! been in a few,..rebuilt 13 speed back boxes few times...but far from expert!! really better at driving than wrenchin on them! takes skills to speed shift a rto 12.5-13!!! makes shifting a 833 a walk in a park!!
Click to expand...
Except old stock ones, with worn out external shifters, and those rubber shift rods, you gotta be on your game with that junk.
 
trapster said:
I have 2 iron 833od, one in my 64 dart, I have 355 limit slip 83/4 stock wheels and a built 340 pushing it .
1st gear is a waste and only gets me to 30ish, if I try to power shift it into second the wheels break loose, but it is really hard to shift it into second. Forget about down shifting into 1st it just wont do it. revs are pretty low in overdrive but it lugs if I am going under 40.
Bottom line is it is OK for just cruising around but if you want to have more fun consider something else.
I have purchased a regular 833 and am going to swap it out as soon as I get all of the parts I need, and time to do it.
Click to expand...

Trapster, I think your odbox may have issues. Mine all shifted just fine; up or down. And why you would lug od down to 40 mph @1300rpm, with a built 340, I cannot understand. And powershifting into 1.67 second gear, and getting wheelspin,is actually a testament to the torque of your engine. IMO none of these are a poor reflection on the odbox.
However, the splits are pretty wide, and if your engine rpm fails to drop rapidly enough, then yes, you can have shifting issues. The slow synchronization may be due to the synchro rings being tired, or the cone-brakes might be highly polished from many miles of useage. There are easy fixes for those.
But as I said these odboxes are not built for high-rpm engines. When I started shifting at 7000/7200 my odbox had trouble synchronizing too.My rpm would not drop fast enough, no fault of the box,but of the design. So I took steps. Steps to make the rpm drop faster, and steps to help the box.
The split is worst on the 1-2, being 54% . So outshifting first at 7000, the rpm has to drop to 3783, or a drop of 3217rpm. That's an awful lot. The standard 2.66 box only drops to 5050, an amount of 1947rpm. But you have to rev it to 7000, to find power at 3783, after the shift. If you shift at 6000, more typical with a streetcam, then the Rs drop to 3240, and a big-cammed engine just has no power down there.
So what I did was street slick-shift my second gear. This allowed me to shift it normally, yet when I'm banging it, I can overpower the brass, and just slam it in there, no more waiting. Second gear with 3.55s is good to 95 mph, and the 2-3 split is tighter at 60%, so this is naturally a slightly faster shift, and I wasn't planning on going any faster.. However, without the slickshifting, I doubt you can powershift one of these; I didn't even try. Besides,my clutch leg was pretty fast in those days.
My 360 with the lightweight KB107s, and 11/1 compression, loses rpm pretty quickly when the throttles slam shut, so after the trans mod worked so well, I didn't get into flywheel swapping. Oh yeah, I dumped the gear oil and started playing with ATF. I ended at 2/1 ratio two parts ATF to 1 part 80/90. This also helped speed up the shifts.
But it only took about one summer for me to see the problem with this design/combo. The next summer I had the GVOD on it, being used as a splitter,Shazzam! Seven gears;
3.09-2.41-1.67-1.30-1.00-.78od-.54od.GVOD in red. and .73 used at the very last. The GV is power-shifted.
I have seen several combos that shouldn't have been using this box. The 1-2 split is just too far apart for high rpm shifting, with a pipey powerband.
 
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AJ/FormS said:
Trapster, I think your odbox may have issues. Mine all shifted just fine; up or down. And why you would lug od down to 40 mph @1300rpm, with a built 340, I cannot understand. And powershifting into 1.67 second gear, and getting wheelspin,is actually a testament to the torque of your engine. IMO none of these are a poor reflection on the odbox.
However, the splits are pretty wide, and if your engine rpm fails to drop rapidly enough, then yes, you can have shifting issues. The slow synchronization may be due to the synchro rings being tired, or the cone-brakes might be highly polished from many miles of useage. There are easy fixes for those.
But as I said these odboxes are not built for high-rpm engines. When I started shifting at 7000/7200 my odbox had trouble synchronizing too.My rpm would not drop fast enough, no fault of the box,but of the design. So I took steps. Steps to make the rpm drop faster, and steps to help the box.
The split is worst on the 1-2, being 54% . So outshifting first at 7000, the rpm has to drop to 3783, or a drop of 3217rpm. That's an awful lot. The standard 2.66 box only drops to 5050, an amount of 1947rpm. But you have to rev it to 7000, to find power at 3783, after the shift. If you shift at 6000, more typical with a streetcam, then the Rs drop to 3240, and a big-cammed engine just has no power down there.
So what I did was street slick-shift my second gear. This allowed me to shift it normally, yet when I'm banging it, I can overpower the brass, and just slam it in there, no more waiting. Second gear with 3.55s is good to 95 mph, and the 2-3 split is tighter at 60%, so this is naturally a slightly faster shift, and I wasn't planning on going any faster.. However, without the slickshifting, I doubt you can powershift one of these; I didn't even try. Besides,my clutch leg was pretty fast in those days.
My 360 with the lightweight KB107s, and 11/1 compression, loses rpm pretty quickly when the throttles slam shut, so after the trans mod worked so well, I didn't get into flywheel swapping. Oh yeah, I dumped the gear oil and started playing with ATF. I ended at 2/1 ratio two parts ATF to 1 part 80/90. This also helped speed up the shifts.
But it only took about one summer for me to see the problem with this design/combo. The next summer I had the GVOD on it, being used as a splitter,Shazzam! Seven gears;
3.09-2.41-1.67-1.30-1.00-.78od-.54od.GVOD in red. and .73 used at the very last. The GV is power-shifted.
I have seen several combos that shouldn't have been using this box. The 1-2 split is just too far apart for high rpm shifting, with a pipey powerband.
Click to expand...



It's not just the OD boxes that don't like shifting at higher RPM. That RPM is dictated by the weight of the disc (mostly). If you think about it...the disc has to speed up and slow down with changing engine speeds. The heavier the disc, the harder it is to speed up and slow down. Add a bunch of RPM to it and it makes it even worse.

The 36 teeth on the gear and inside the sliders is too fine to allow the synchro to slow things down enough to make heavy disc, high RPM shifting clean. That's why slick shifting, pro shifting and face plating make it easier to shift.

On my drag stuff I slick shifted them until I tore them up or wore them out. Then I had them pro shifted. On the street I slick shift the gears, sliders and syncros. I've shifted as high as 8k with a sintered iron disc. And it up and down shifts like a stock box.
 
Chatter inside the quote
yellow rose said:
It's not just the OD boxes that don't like shifting at higher RPM.agreed That RPM is dictated by the weight of the disc (mostly). If you think about it...the disc has to speed up and slow down with changing engine speeds. The heavier the disc, the harder it is to speed up and slow down. Add a bunch of RPM to it and it makes it even worse. Agreed; the disc is "attached" to the input gear. The brass can only do so much. And that's why the 3217 rpm drop at 7000,with brass only, for me ,was unacceptable. The GVOD splitter changes that to 1540. And after I swapped back to the deep-low box, the splits got even tighter. The shift from 1-od into second is .80, and at 6000, (all ready a high shift rpm for a 230* cam), this is just 1200 rpm, and from second to 2od is just 1320 rpm. And second-od gets me 93@6140, and my eighth is done. 4 ratios to get there, two of them electric power-shifted and one tug on the stick.
In the deep-low box, I slick shifted only second and third, leaving the brass in . I don't get into 4th when banging,until over 100 with 3.55s, and that very rarely ever happens. So I left that one alone.
The 36 teeth on the gear and inside the sliders is too fine to allow the synchro to slow things down enough to make heavy disc, high RPM shifting clean. That's why slick shifting, pro shifting and face plating make it easier to shift.Agreed

On my drag stuff I slick shifted them until I tore them up (ouch)or wore them out. Then I had them pro shifted. On the street I slick shift the gears, sliders and syncros. I've shifted as high as 8k with a sintered iron disc. And it up and down shifts like a stock box. (Nice)
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Marcohotrod said:
Kelster-what is your rear gear and tire size? 3000 at 70 is no big deal. change oil + filter more. go to a taller rear tire. the 1:1 gear in an overdrive, call it whatever is strong-the same as all a833 units-I ran 12s with around 450 torque, and the overdrive gear is strong too. call it a 4 gear. my buddy, seaweed the junkmaster , sold me this unit cheap, all aluminum with an iron sidecover and iron front bearing retainer, we turned down the front bearing retainer to 4.80", easier than enlarging the bellhouse (if u have a 4.35" house-not so) and 27 spline output, 308 front bearing, and I banged on it for a few years no problemsView attachment 1715136855
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Hey! I bought that tranny off you a few years ago!
 
A lot of manual transmissions that have a lower than usual first gear, that first gear is not synchronized. I know this is true with the older "granny gear" transmissions like the one in my truck, the Borg Warner T-18, as well as the NP435. This is why you cannot shift into first until almost stopped and also why you cannot speed shift them. They are simply not designed for it.

I do not know enough about the 833OD transmissions to know if first gear is synchronized or not, but that could certainly answer the question.
 
All my833s have been fully synchronized,od or not, as was the A230

But the A745 and A903, three-speeds were not
I think the 230s debuted behind the 340s in the 1970 model, then were the only 3-speed from 71on, or so.
 
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