hi im looking to build my 3spd auto for my turbocharged 2200. i cant seem to find parts anywhere and i dont know what the weak points are so i can get them fixed. If anyone has done this please reply cause i need help on this
I used to have one lol. Too bad I didn't hang onto it.
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Yea, ummmm. I used to have a J-body...
Alto-Red Eagle has the best Frctions and Koline Steels you can get. Look into their catalog for their rebuild kits.
TransGo has a performance shift kit, though it is not listed on their website. You should be able to get it at any performance trans. shop or better independantly owned shops.
Look for a good high performance/racing torque converter company, that does custom TCs. Call them and they can build you a good TC, that will hold the power of a boosted motor and get you the right stall speed.
If your using an aftermarket cam, call the cam manufacturer and find out what gearing will work best with your car. There were three different gear ratios available in the final drive(differential). Most J-Bodies with the 3 speed(3T40/TH125C) came with the 2.84:1 diff., along with the underdriven chain drive, gave an effective gear ratio of 3.18:1. Switching to the 3.08:1 diff will give you a 3.43:1eff.ratio, or the 3.33:1 diff for a 3.73:1 eff. ratio. To find your gear ratio, look for your RPOs located on the spare tire cover in the trunk and get your RPOs decoded, it's in the jumble of letters and numbers.
Finally have that trans shop you found for above, do a rebuild on it, using the parts listed above. The three speed might be the slowest, in stock form, but is the strongest of the transmissions and can be just as fast as any other tranny in a J, but only if it's built correctly. Use the advanced search at the top of this forum for more details.
I wouldn't advise the install of a shift kit in a modern trans. It might help in a previous generation. Torque Management isn't going to like it. It will pull timing further.
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Yea, ummmm. I used to have a J-body...
thank you for the input, i think i am going more towards a manual valve body job so it drives like a stick. i just wasnt sure what kind of other performance parts they had for that tranny, like sprags and input shafts.
David S, The Camaro Guy. wrote:I wouldn't advise the install of a shift kit in a modern trans. It might help in a previous generation. Torque Management isn't going to like it. It will pull timing further.
i don't believe that any of the cars that came with the TH125 had torque management...
and to go along with what madjack was saying, here's a calculator to help you figure out what rpm you'll be at for what mph with any of the 3 final drives... that way you don't pick one and end up surprised that your engine is revving REALLY high at the same speed that it used to rev much lower....
http://www.angelfire.com/fl/procrastination/rear.html
Arrival Blue 04 LS Sport
Eco
Turbo
Megasquirt
'Nuff said
David S, The Camaro Guy. wrote:I wouldn't advise the install of a shift kit in a modern trans. It might help in a previous generation. Torque Management isn't going to like it. It will pull timing further.
Nope, no torque management in the TH125C/3T40. It basically operates just like the old TH350. Actually more like the TH350C due to the TCC, and instead of a vacum modulator it uses a mechanical TV. The only electroncis in these is the VSS and the TCC lock-up solinoid. The only contol the PCM has on it is if the PCM senses slippage between the engine rpm and the VSS, while the TCC is engaged, it will cut power to the TCC solinoid. Other than that everything is controled by the valve and line pressure.
Does my old heart good to hear someone praise the ol' 3 speed.
Quote:
The three speed might be the slowest, in stock form, but is the strongest of the transmissions and can be just as fast as any other tranny in a J, but only if it's built correctly.
Lordy, that'll have to be next.
Look at your spark timing between the shifts. It is greatly pulled. I dare you to look.
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Yea, ummmm. I used to have a J-body...
Here is an example of your PCM pulling the timing back to almost 0 and that is with a stock car.
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Yea, ummmm. I used to have a J-body...
Thats a 4 speed graph, Count your shifts. Also, note that the timing is pulled right at or just before the shift.
The PCM doesn't know when your tansmission is shifting, because the valve body controls the shift, not the pcm. How could the PCM know what the line pressure differential is, without any pressure sensors? The same occurs in the manual tranny cars, how would it know when your going to shift?
There is Torque Management used in the 4sp 4T40
E, which is controled by the PCM.
The original TH125 came out in 1982, in the first gen J's and other FWD applicatios using L4 and smaller V6s. In 1987, it was upgraded to the TH125
C, with the addition of the TCC. In the early '90s it was redesignated the 3T40.
You could program the PCM to pull timing when it sees a drop of RPM but the MAP sensor is still high.
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Yea, ummmm. I used to have a J-body...
i have found that J-tuners now has a torque converter that works with j's and its stalls at 3000 rpm I think i will get it when i go turbo with my 2200 sunfire.
'99 2.2 OHV w/3spd auto (work in progress)
http://www.cardomain.com/ride/2322134
You may not rev higher at certain speeds depending on how much power you make granted you can't idle at 70 mph though that would be nice for fuel savings, also a high stall converter will change your rpm at different speeds but hey im willing to live with that if it means going faster.
'99 2.2 OHV w/3spd auto (work in progress)
http://www.cardomain.com/ride/2322134
That's the TC I've got. It's the best mod for any auto J-Body. That's a good price, considering Yank used to sell them for much more. Yank had discontinued them, but because of demand, I think are doing limited runs, such as they are doing with J-Tuners.
Even though I didn't buy it from them, I left a good review on J-Tuners.
