904 lockup vs non lockup

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dartfreak75

dartfreak75

Restore it, Dont part it!
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Hey guys I have two transmissions to use one is a non lock 904 it came off my 360 which is a 77 model. The other is a lockup which came off the engine I'm rebuilding it's a 86 318. I have the original torque converter for each one i know they will not interchange. Which is the better one. What are the pros and cons of each and which one would you use and why? Thanks
 
I personally like non lock up. If the '86 has a low gear first gear, you can put it in the other. I'm not personally a transmission specialist, changed enough of them, though :D
 
I chose to go with the lockup in mine.
Lower 1st gear ratio and the lockup will benefit me at cruising speed.
Im not racing,just slow speed shenanigans...
 
AJ/FormS said:
That would depend on your power, your torque,your rear gear, your cam,your compression, traction,weight, and your application.
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Well I have a 318 with a 4bbl headers going with a lunati voodoo 10200701 cam 256 duration 454 lift 8.6:1 compression rear gear is 2.76 (for now plan on using a 3.73 limited slip 8.8 later on) weight is probably around 3400+ with me in it. I think traction will be a problem with a pretty much stock 318. And the application is just a weekend cruiser something to play around in. Most of my driving will be on the highways and backroads (35-60 mph) but will hit the interstate from time to time (70+ mph)
 
dartfreak75 said:
Well I have a 318 with a 4bbl headers going with a lunati voodoo 10200701 cam 256 duration 454 lift 8.6:1 compression rear gear is 2.76 (for now plan on using a 3.73 limited slip 8.8 later on) weight is probably around 3400+ with me in it. I think traction will be a problem with a pretty much stock 318. And the application is just a weekend cruiser something to play around in. Most of my driving will be on the highways and backroads (35-60 mph) but will hit the interstate from time to time (70+ mph)
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Well then A999loc-up it is, and don't expect too much from second gear.
Why the 999? Because with a 2.76 rear your TM on the line will be 2.76x2.74= 7.56. The loc-up with the 256cam might stall at 2200. And you might be making 200 ftlbs there. So 200 x 7.56= 1512 ftlbs on the start line. With a lil shot from the TC she might chirp the two rear tires. No SG? then it doesn't much matter. But with the 904 your TM is only 2.45x2.76=6.76 and the TC might be an 1850. Your torque might be 180 so; 180x6.76= 1217 ftlbs on the start line, just enough to squeal one tire and torture the one-legger7.25.

Now if you had a 2800TC then I would use the 904 cuz you will benefit from the closer 1-2 split, especially later, with the 3.73s . This combo will get you ~40 mph at the top of first. And the rpm drop into second will be to ~3100(with the 904), instead of 2900@37mph (with the 999). Either way it's a long pull to 60, but 200rpm and 3 mph is harder,lol.
 
AJ/FormS said:
Well then A999loc-up it is, and don't expect too much from second gear.
Why the 999? Because with a 2.76 rear your TM on the line will be 2.76x2.74= 7.56. The loc-up with the 256cam might stall at 2200. And you might be making 200 ftlbs there. So 200 x 7.56= 1512 ftlbs on the start line. With a lil shot from the TC she might chirp the two rear tires. No SG? then it doesn't much matter. But with the 904 your TM is only 2.45x2.76=6.76 and the TC might be an 1850. Your torque might be 180 so; 180x6.76= 1217 ftlbs on the start line, just enough to squeal one tire and torture the one-legger7.25.

Now if you had a 2800TC then I would use the 904 cuz you will benefit from the closer 1-2 split, especially later, with the 3.73s . This combo will get you ~40 mph at the top of first. And the rpm drop into second will be to ~3100(with the 904), instead of 2900@37mph (with the 999). Either way it's a long pull to 60, but 200rpm and 3 mph is harder,lol.
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I don't have a 999 I have a 904. Lol I'm asking between a lockup 904 vs a non lockup 904.
 
toolmanmike said:
:BangHead::BangHead: I tossed a lock up a few years ago. :BangHead::BangHead:
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I scraped a perfectly good 904 because it was off a slant six and I didnt know all the internals where the same. I would have had an extra valve body and all the other internals but I didnt know any better oh well you live and learn.
 
A904 has ratios of 2.45-1.45-1.00 and is a non loc-up. whereas
A999 has ratios of 2.74-1.54-1.00 and is a lock-up trans.The
A998 should have the A999 ratios and should come without the loc-up.
That is my conclusion.
The higher the number the more HD the guts are..... from the factory. The loc-up TC is probably the weakest link tho. But it usually comes with a slightly higher stall. All are strong enough for your 318.
I have a 998 with a 2800Tc and a stock lo-compression long-block 1973 318. With a 4bbl,headers,dual 3" full length pipes,and 3.55s; she's a gem.... with 4.30s she was a ripper.
 
AJ/FormS said:
A904 has ratios of 2.45-1.45-1.00 and is a non loc-up. whereas
A999 has ratios of 2.74-1.54-1.00 and is a lock-up trans.The
A998 should have the A999 ratios and should come without the loc-up.
That is my conclusion.
The higher the number the more HD the guts are..... from the factory. The loc-up TC is probably the weakest link tho. But it usually comes with a slightly higher stall. All are strong enough for your 318.
I have a 998 with a 2800Tc and a stock lo-compression long-block 1973 318. With a 4bbl,headers,dual 3" full length pipes,and 3.55s; she's a gem.... with 4.30s she was a ripper.
Click to expand...
So all 999s are lockup? If that is the case then mine is not a 999 because it is not a lockup. It has the fully splined input shaft. (The 360 one) the 86 is clearly a lockup it has the partially spline input shaft and the TC has a sticker on it saying lockup!
 
The 360 trans will have a 5 clutch drum from the factory. The 318 trans will be 4 clutch drum and a slant will have 3 clutches. I vote for the 360 trans, cause if u upgrade later it will handle the power better. Kim
 
I run a 999 lockup with lockup delete, brass plug in TCC port, Turbo Action 10" S800 tight converter, 340/400hp. 400 passes and works great.
 
Drop the front drums out of both to see what you have. Leave the output snap ring and the tailshaft housing in place for now. One step at a time. Count the clutches. Post pics of the back of the pumps.
 
Ok so this morning I pulled out the transmission from storage and according to the link above I infact have a non lockup 999. I'm not sure if that Is a good thing or not but judging from yalls posts I'm assuming it's good. Here is the pk #

20181114_074730.jpg
 
oldkimmer said:
The 360 trans will have a 5 clutch drum from the factory. The 318 trans will be 4 clutch drum and a slant will have 3 clutches. I vote for the 360 trans, cause if u upgrade later it will handle the power better. Kim
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All those lockup 318 999 trans come with the five clutch front drum.
With the exception of the lockup, they were the best strongest versions of the 904 trans. I use them exclusively in my drag car for that reason. I swap in slant 6 pump and input shaft to get rid of the lockup and one small minor machining operation to make it work.
Those 999 have 4 pinion steel planetaries, 5 clutch front drum, best thrust washer version between the input and output shaft, thicker beefier output support,beefier reverse drum,bigger sprag,2.74 first gear,double wrap rear band. People shy away from them for all the wrong reasons. IMHO
 
3forty said:
When are going to "crack open" the A999?
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Soon i guess my engine build just got stalled so I guess I can put some attention to the transmission. I am gonna need some walk thru assistant I'm sure. I put a shift kit in a 904 years ago but that is as deep as I have ever been.
 
oldkimmer said:
The 360 trans will have a 5 clutch drum from the factory. The 318 trans will be 4 clutch drum and a slant will have 3 clutches. I vote for the 360 trans, cause if u upgrade later it will handle the power better. Kim
Click to expand...
Those mid to late eighties lockup 318 904,s all had the good 5 clutch drum in them and the low gear. They were the best 904,s internally except the lockup feature.
 
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