833 OD sticking in 4th, chipped synchro
- Thread starter dhowlan
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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If the new struts are dimensionaly the same as the old, and you install them; I can almost guarantee you that you will end up having the same problem ....... down the road.
The struts are captured by the brass, and limited in travel by the distance between the bottoms of the slots. As the brass wears, they creep up the brake cones, and the inter-slot dimension grows. This allows more space for the struts to come out and eventually they are able to pop out the back.
New struts will not solve this. You have to reduce the inter-slot dimension, by one of the following three ways;
1) install new brass that sits higher up away from the clutch teeth, or
2) move the mainshaft forward, or
3) move the Input gear deeper into the case.
Since all A833s that I have worked on, have this design problem, I just move the input gears back in the first place.
I should mention that if your box runs too hot, the brass will expand and climb down the brake towards the clutch teeth, opening up the inter-slot dimension; leading to strut pop-out.
However, the over-heated brass turns color, and yours are still bright yellow, so this is not your problem.
But Since you have it apart, check the faces of the brass for signs of having run that deep and throw those away.
Another thing I do is attempt to stretch the brass,, looking for broken ones.
The struts are captured by the brass, and limited in travel by the distance between the bottoms of the slots. As the brass wears, they creep up the brake cones, and the inter-slot dimension grows. This allows more space for the struts to come out and eventually they are able to pop out the back.
New struts will not solve this. You have to reduce the inter-slot dimension, by one of the following three ways;
1) install new brass that sits higher up away from the clutch teeth, or
2) move the mainshaft forward, or
3) move the Input gear deeper into the case.
Since all A833s that I have worked on, have this design problem, I just move the input gears back in the first place.
I should mention that if your box runs too hot, the brass will expand and climb down the brake towards the clutch teeth, opening up the inter-slot dimension; leading to strut pop-out.
However, the over-heated brass turns color, and yours are still bright yellow, so this is not your problem.
But Since you have it apart, check the faces of the brass for signs of having run that deep and throw those away.
Another thing I do is attempt to stretch the brass,, looking for broken ones.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I do not think moving the M/S forward is an option in that trans.
>As to the front snapring; I do not recall the thickness of the factory ring. .064 sounds a lil thin, but I just don't remember. So;
lay the gasket onto the retainer and slip the big snap ring into the receiver-step. Make sure it sits below the gasket. It has to sit below the gasket, else either the retainer will break when you tighten it up, or it will leak.
>By the same token;
If after you mount the input gear into the case and bolt the retainer on, the whole thing moves back and forth, something is wrong. and most likely would be that the wrong thickness gasket is being used, but could also be a too-thin outter snapring. So figure that out first.
Your goal is to move only the input gear back. Once the correct relationship is restored as to the large snapring, then you can see about the small one. Here your only choice is to put the thinnest snapring that you can find into the groove, and move the bearing up tight to it, then measure between the input and the bearing, and install whatever shims you can get, into there. I used to use rear-end shims, left over from the days I was a rebuilder, some 40 years ago..
Now, before you spend a lotta time on this, consider that you're not gonna get much. It is usually much more advantageous to just install a new hi-riding brass on both of those gears, which will instantly restore the inter-brass distance, to the factory measurement.
>And once again I highly recommend NOT to install any synthetic oil into that box. It is too slippery, and will either delay your shifts or else you will get impatient and ram it into gear, which will chip off your clutch teeth. I use 50/50 Dextron-II and EP 85/90. You can use whatever EP oil you have; just make sure it does NOT contain any additives for any type of Limited Slip Differential. This EP oil is only in there to protect the Cluster pin.
>Finally, that od box has very-wide ratios, same as any Mopar 3-speed, so it's NOT a hi-perf box, and so; don't try to get hi-perf out of it. If your engine is slow to rev or more importantly the revs don't fall in a hurry, either fix that, or go easy on the trans.
>The ratios are; 3.09-1.67-1.00-.73od with splits of; .54-.60-.73.. The regular
4-speed is .... 2.66-1.92-1.40-1.00 with splits of; .72-.73-.71
What the splits mean, is that at whatever rpm you out-shift at, the in-shift rpm of the next gear will be at those percents.
Say you outshift yours at 5000 rpm;
54% of 5000 is an in-shift rpm into Second of 2700 for a drop of 2300. Now with the regular 4-spd, still outshifting First
at 5000, your inshift into Second will be to ... 3600 a drop of just 1400.
So like said, yur gonna have to wait for the Rs to come down.
The picture is only a tiny bit better at 3000, the Rs still have to come down to those percents.... so you still gotta wait, just not quite as long.
>After reassembly, keep after your clutch-departure, so the brass doesn't have to work so hard, trying to slow the engine down. This means; keep your hand OFF the shifter, except to shift, and don't bother downshifting into direct, unless circumstances require it. Be nice to that brass and it will last a really long time. Another thing to keep in mind is if the car is slowing down too fast. This could be due to; dragging brakes, very low tire pressure, excess baggage/towing, terrain, or road surfaces.
If your engine is slow on the deceleration, my guesses are;
A heavy flywheel
lack of cylinder pressure,
insufficient clutch-departure
throttle open too far
running too rich
lack of timing advance.
Lord help you if she has all of those problems, lol.
>As to the front snapring; I do not recall the thickness of the factory ring. .064 sounds a lil thin, but I just don't remember. So;
lay the gasket onto the retainer and slip the big snap ring into the receiver-step. Make sure it sits below the gasket. It has to sit below the gasket, else either the retainer will break when you tighten it up, or it will leak.
>By the same token;
If after you mount the input gear into the case and bolt the retainer on, the whole thing moves back and forth, something is wrong. and most likely would be that the wrong thickness gasket is being used, but could also be a too-thin outter snapring. So figure that out first.
Your goal is to move only the input gear back. Once the correct relationship is restored as to the large snapring, then you can see about the small one. Here your only choice is to put the thinnest snapring that you can find into the groove, and move the bearing up tight to it, then measure between the input and the bearing, and install whatever shims you can get, into there. I used to use rear-end shims, left over from the days I was a rebuilder, some 40 years ago..
Now, before you spend a lotta time on this, consider that you're not gonna get much. It is usually much more advantageous to just install a new hi-riding brass on both of those gears, which will instantly restore the inter-brass distance, to the factory measurement.
>And once again I highly recommend NOT to install any synthetic oil into that box. It is too slippery, and will either delay your shifts or else you will get impatient and ram it into gear, which will chip off your clutch teeth. I use 50/50 Dextron-II and EP 85/90. You can use whatever EP oil you have; just make sure it does NOT contain any additives for any type of Limited Slip Differential. This EP oil is only in there to protect the Cluster pin.
>Finally, that od box has very-wide ratios, same as any Mopar 3-speed, so it's NOT a hi-perf box, and so; don't try to get hi-perf out of it. If your engine is slow to rev or more importantly the revs don't fall in a hurry, either fix that, or go easy on the trans.
>The ratios are; 3.09-1.67-1.00-.73od with splits of; .54-.60-.73.. The regular
4-speed is .... 2.66-1.92-1.40-1.00 with splits of; .72-.73-.71
What the splits mean, is that at whatever rpm you out-shift at, the in-shift rpm of the next gear will be at those percents.
Say you outshift yours at 5000 rpm;
54% of 5000 is an in-shift rpm into Second of 2700 for a drop of 2300. Now with the regular 4-spd, still outshifting First
at 5000, your inshift into Second will be to ... 3600 a drop of just 1400.
So like said, yur gonna have to wait for the Rs to come down.
The picture is only a tiny bit better at 3000, the Rs still have to come down to those percents.... so you still gotta wait, just not quite as long.
>After reassembly, keep after your clutch-departure, so the brass doesn't have to work so hard, trying to slow the engine down. This means; keep your hand OFF the shifter, except to shift, and don't bother downshifting into direct, unless circumstances require it. Be nice to that brass and it will last a really long time. Another thing to keep in mind is if the car is slowing down too fast. This could be due to; dragging brakes, very low tire pressure, excess baggage/towing, terrain, or road surfaces.
If your engine is slow on the deceleration, my guesses are;
A heavy flywheel
lack of cylinder pressure,
insufficient clutch-departure
throttle open too far
running too rich
lack of timing advance.
Lord help you if she has all of those problems, lol.
Last edited:
dhowlan
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Brewers has that snap ring listed at .065 so I think it's fine. I'll check the play with the new gasket etc. when I get there.
I'm aware of the limitations of this flavor of a833. I had a long time to stew on swapping to another option. It's fine for the slant.
I'm guessing I will subconsciously be more gentle in the 3-4 shift in the future regardless.
Thanks for the input. Parts are supposed to arrive Friday.
I'm aware of the limitations of this flavor of a833. I had a long time to stew on swapping to another option. It's fine for the slant.
I'm guessing I will subconsciously be more gentle in the 3-4 shift in the future regardless.
Thanks for the input. Parts are supposed to arrive Friday.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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I wasn't knocking your transmission selection.
I myself ran that trans for a couple of years behind a stout 367.
to make it a high-rpm runner, I know what to do
But in the end, I let it go.
BTW;
I want to give you some food for thought:
I am currently using the Commando with ratios of 3.09-1.92-1.40-1.00 / With 3.23s (no longer in the car) the Road gears were;
-------9.98--6.20-4.52-3.23-- if you ran 3.73s with that od box, your roadgears would be
11.53------6.23----3.73---2.72 ; and 65=2475 with a 24" tire. This is actually a pretty good set-up for a slanty
Notice Second gears are the same.
To cruise any slower and still get better fuel-economy would be difficult because of the near impossibility to provide enough ignition advance with the factory type distributor. So that's two gears in your favor.
As for the 11.53 starter gear, while being pretty doggone low, it's a really good parade gear, and a dump-it-and-go starter gear. But Second gear comes along pretty fast. First gears this high are hard to rate, with the small 24" tires. The 3.73 roadgear is pretty good because with it 40 mph is ~2100, a good place to be cruising at in the city. So that's 3 out of 4 not too bad.
You may have other ideas, and that's fine, the real point I'm trying to make is that down below about 2400 it is no longer possible to meet the engines timing requirement, and fuel-economy will begin to suffer because of that. To find out how much timing your engine wants at any cruise rpm, just rev it up to the chosen rpm and read the current advance.
Then, keep giving it advance while simultaneously keeping the rpm at the set point. When the rpm no longer rises with additional advance, read the timing and subtract about 2 or 3 degrees for the load, and that is your magic number. Now put the timing back and return the engine to idle. Finally, compare what the engine wants to what your distributor is currently giving, then figure out if she can be modified to supply the difference.
Don't be surprised to see a requirement of over 50* at 2400rpm.
If you cruise below the magic number, you can expect that whatever savings that the lower rpm might be worth, is lost to the lack of efficiency due to not enough timing. They sorta run neck and neck but in opposite directions.
You can try this at say 200 rpm intervals from 1600 to 2800, then modify your distributor as best as you can, and plot the two sets of numbers on a graph to see where they intersect, and badaboom, there is your optimum cruising rpm.
Now you just have the carb to deal with, lol.
If you really want to cruise below 2200 and simultaneously get optimum fuel economy, then, you will need a stand-alone, aftermarket, dash-mounted, dial-back , timing module. Mine has a range of 15 degrees. or a timing computer.
Happy HotRodding.
I myself ran that trans for a couple of years behind a stout 367.
to make it a high-rpm runner, I know what to do
But in the end, I let it go.
BTW;
I want to give you some food for thought:
I am currently using the Commando with ratios of 3.09-1.92-1.40-1.00 / With 3.23s (no longer in the car) the Road gears were;
-------9.98--6.20-4.52-3.23-- if you ran 3.73s with that od box, your roadgears would be
11.53------6.23----3.73---2.72 ; and 65=2475 with a 24" tire. This is actually a pretty good set-up for a slanty
Notice Second gears are the same.
To cruise any slower and still get better fuel-economy would be difficult because of the near impossibility to provide enough ignition advance with the factory type distributor. So that's two gears in your favor.
As for the 11.53 starter gear, while being pretty doggone low, it's a really good parade gear, and a dump-it-and-go starter gear. But Second gear comes along pretty fast. First gears this high are hard to rate, with the small 24" tires. The 3.73 roadgear is pretty good because with it 40 mph is ~2100, a good place to be cruising at in the city. So that's 3 out of 4 not too bad.
You may have other ideas, and that's fine, the real point I'm trying to make is that down below about 2400 it is no longer possible to meet the engines timing requirement, and fuel-economy will begin to suffer because of that. To find out how much timing your engine wants at any cruise rpm, just rev it up to the chosen rpm and read the current advance.
Then, keep giving it advance while simultaneously keeping the rpm at the set point. When the rpm no longer rises with additional advance, read the timing and subtract about 2 or 3 degrees for the load, and that is your magic number. Now put the timing back and return the engine to idle. Finally, compare what the engine wants to what your distributor is currently giving, then figure out if she can be modified to supply the difference.
Don't be surprised to see a requirement of over 50* at 2400rpm.
If you cruise below the magic number, you can expect that whatever savings that the lower rpm might be worth, is lost to the lack of efficiency due to not enough timing. They sorta run neck and neck but in opposite directions.
You can try this at say 200 rpm intervals from 1600 to 2800, then modify your distributor as best as you can, and plot the two sets of numbers on a graph to see where they intersect, and badaboom, there is your optimum cruising rpm.
Now you just have the carb to deal with, lol.
If you really want to cruise below 2200 and simultaneously get optimum fuel economy, then, you will need a stand-alone, aftermarket, dash-mounted, dial-back , timing module. Mine has a range of 15 degrees. or a timing computer.
Happy HotRodding.
dhowlan
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To follow up, it's back together and back in the car. All 4 gears plus reverse work in and out (at least for the 5 miles it's done so far). Reverse was a nuisance until I realised I had flipped the lever over. Doesn't work that way. Fingers crossed it lasts another 20 years before I have to redo this.
I appreciate all the assistance.
I appreciate all the assistance.
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