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Shakercars's 1972 Trans Am

2019 August
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Rodimus_Prime

I think i blew the torque converter

Question

so coming home tonight was on the on ramp and punched it and the revs just shot up like it was in nuetral did it in overdrive and in drive

The car is fine under light acceleration but the moment you give it too much pedal its like its not grabbing. I know nothing about automatics.

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moved to questions and concerns.

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i dont know much about automatics myself but i think your torque converter is shot as well. if the gears are not grabbing with excessive power, its like a slipping clutch and almost will react the same way from my understanding. (please correct me if im wrong)

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The 700R4 was only rated for about 350HP when it was new, and I'm assuming you have the original tranny, or a OEM replacement. That being said, I know most 700R4s start to give at around 300 HP, despite their rating. Considering that your car put out 250HP, stock, and you have done many-a-mod to the engine, I'd say you probably wrecked something in there, and I wouldn't be surprised if it was the torque converter.

All that being said, I don't know how much power you make. Having looked at your mods, I'm sure it's above 300 horses by now. You might want to look into getting a Pro-Built (the company) transmission, especially if you plan on putting a beefier turbo in there. They sell rebuilt 700R4s that take craptons more power than stock. (I think they're lowest rated 700R4 is, like, 550HP).

Good luck with the Third Gen, from a fellow Third Gen owner :dancingpontiac:

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I have the 200-4R but from what i understand it was some sort of rebuilt tranny that was in there

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your torque converter CAN go out, but more than likely its your CLUTCHES AND BANDS. didnt know your auto had clutches huh?

check your fluid, what color is it, and does it smell burnt? dont bother trying to change it yet, because once an auto goes, changing fluid only makes it worse

see your clutches and bands have friction surfaces on them. when they wear down and wear out, the bits o friction end up in your fluid. new fluid simply cleans what friction surface was left OFF since auto trans fluid cleans so well.

the band in your trans is like a belt that tightens around a drum to engage a certain gear. this get out of adjustment and need tightening sometimes, but since it does it in any gear im gonna guess that tightening the band will do you no good.

you need to look for a GOOD automatic transmission rebuild place near you. find out what he will rebuild you trans for, and how much to remove and replace. it may save you a good bit of money if you can take it out yourself and take it to him. (id say 350 to 400 is fair if he doesnt remove and replace, 6-700 if he does) also, if you want upgraded parts for your trans, i suggest WHATEVER IT TAKES they make bulletproof parts for auto transmissions. my teacher in auto tech was a transmission wizard and had me order my 700r4 parts from there. he told me what to get, and with the parts i got my trans is rated for a touch over 1100 hp :lol2: i went overkill because its going in a big 4wd truck :lol2:

GOOD LUCK

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i honestly dont want to put 1000-2000 into the thing, im considering getting out of it all together and just cut my losses now

I talked to a guy in NY that can do the job but I'd have to get the tranny out and up to him

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i honestly dont want to put 1000-2000 into the thing, im considering getting out of it all together and just cut my losses now

I talked to a guy in NY that can do the job but I'd have to get the tranny out and up to him

good luck man. hope you get it.

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This is going to sound stupid but bear with me.

If your engine revs when you punch it, How old is your fluid? Is the fluid at capacity?

Check those first before you go to the worst case senario. Also check your TV cable and see if it snapped.

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Oh! That reminds me! The TV Cable in most third gens is adjustable. Maybe it ratcheted out of adjustment. Or snapped.

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ONLY PUT IN FLUID IF ITS LOW!!!!

DO NOT CHANGE FLUID IF IT SMELLS BURNT (if you are trying to limp it around) for the reasons prescribed in my previous post.

you CAN try and change the fluid and there is a SMALL possibility your trans will come back, but almost always if its already slipping and it smells burnt, changing the fluid will only make your car stationary. i did a guy's chevy truck w/turbo350 trans and i warned him that most likely it would just make the trans give up 100% he said change it anyway and i did. then he tried to not pay me when the car didnt move afterwards. I WARNED HIM one day karma will flatten all his tires....

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ONLY PUT IN FLUID IF ITS LOW!!!!

DO NOT CHANGE FLUID IF IT SMELLS BURNT (if you are trying to limp it around) for the reasons prescribed in my previous post.

you CAN try and change the fluid and there is a SMALL possibility your trans will come back, but almost always if its already slipping and it smells burnt, changing the fluid will only make your car stationary. i did a guy's chevy truck w/turbo350 trans and i warned him that most likely it would just make the trans give up 100% he said change it anyway and i did. then he tried to not pay me when the car didnt move afterwards. I WARNED HIM one day karma will flatten all his tires....

;) turbo200, turbo350, 400's trannys ect. you either change the oil on a regular basis or you leave it the F alone for ever practically. Never once in a blue moon and if its on its way out never ever touch the oil.

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I have no idea what a TV cable even is much less how to change it

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TV cable hooks one end to the transmission and the other end to the throttle linkage. The cable is used to regulate the pressure in the transmission for shifting based on the throttle position. It is kinda pain to change which usually involves dropping the pan and disconnecting it. The linkage at the throttle body or the carb just hooks up similar to the throttle cable. It has been some years since I changed one but I remember I was not very good at setting it up.

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i thought that cable only controlled the kickdown as in if you punch it and it downshifts. how would this make the trans slip?

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On the 200r4 and the 700r4 it controls line pressures for the shifting. If there is not enough line pressure sometimes the trans will get lost between gears and the transmission will slip. An incorrectly calibrated TV cable will dramatically shorten the life of the transmission. The kickdown cable was on the TH350, 250 and the only thing it would do is control the kickdown. (ie foot to the floor) On the TH400 this is an electric solenoid controlled by the pedal position.

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fluid in the dipstick looked full and brand new

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I cannot remember is there a vacuum line from the intake manifold to the side of the transmission?

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maybe?

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so i found out some interesting info today apparently I checked the tranny fluid wrong, its supposed to be with the car on or warm after running, i had the car off and cold and the level was much lower, apparently also your supposed to actually overfill it by 3/4 of a quart for best performance on the GM 200-4R

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so i found out some interesting info today apparently I checked the tranny fluid wrong, its supposed to be with the car on or warm after running, i had the car off and cold and the level was much lower, apparently also your supposed to actually overfill it by 3/4 of a quart for best performance on the GM 200-4R

If you have the car on, you should shift through all the gears, as well, then check.

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so i found out some interesting info today apparently I checked the tranny fluid wrong, its supposed to be with the car on or warm after running, i had the car off and cold and the level was much lower, apparently also your supposed to actually overfill it by 3/4 of a quart for best performance on the GM 200-4R

If you have the car on, you should shift through all the gears, as well, then check.

:willy_nilly:

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eh damnit its still doing it ;)

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you know what, have you checked for any leaks at all? my friends eclipse GSX had a similar problem from what i remember and it was because he was leaking tranny fluid. whenever he would punch it, it would rev like in neutral instead of just accelerate like normal.

you might have checked but thats really what i can think of. i know the eclipse is nothing compared to the TA turbo but both are turbo'd cars and do have a rear diff. just a thought. hope this helps.

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Well I decided to fix something pretty much unrelated which is the rear end diff.

I added the gm posi stuff first then it took about 2 qts or so of the 75w90, good thing is everything looked great in there, pretty much like new, no metal bits, shavings, or teeth missing, old oil smelled terrible and sort of baby shit green.

When I first got the car I was told there was some leaking from the diff cover but I never addressed it. There was barely over a quart that came out into the drain pan. While I'm sure thats a problem I still have the issue at highway speed where the entire drivetrain feels like its vibrating. I'm not sure if its wheels out of balance, or wheel bearings, I'm running out of stuff to replace.

This was also my first good look under the rear of the car, good lord the stock suspension pieces are junk. Thin ass U shaped control arms and that piece that goes from side to side over top the axle.

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When I first got the car I was told there was some leaking from the diff cover but I never addressed it. There was barely over a quart that came out into the drain pan. While I'm sure thats a problem I still have the issue at highway speed where the entire drivetrain feels like its vibrating. I'm not sure if its wheels out of balance, or wheel bearings, I'm running out of stuff to replace.

This was also my first good look under the rear of the car, good lord the stock suspension pieces are junk. Thin ass U shaped control arms and that piece that goes from side to side over top the axle.

Could be a balance issue, or maybe a bad u-joint. And I believe you're talking about the rear sway bar. Those things are tiny on thirdgen's, and rust like crazy.

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