I recently replaced my 700r4 in my 89 Firebird. I replaced it with one out of a junk yard. It only had 30,000 miles on it. But there has been a problem with it ever since it was put in the car. I'll try to explain the problem as best as I can. When the car is in overdrive everything seems to be fine. But if I downshift to drive and my foot is off the gas it feels like the car is in neutral, when I put my foot on the gas it revs up (like in neutral) till about 1300 rpms then its normal when my foot is on the gas but as soon as I let off the gas again the rpm's drop quickly to about 600 rpms(like the car is in neutral again). It gets worse if I try to manually downshift. If I manually downshift down to 2 I can't even feel it downshift. It does the same thing as I said above but when I put my foot on the gas it revs up to about 2500 rpms then it engages in second gear. It does the same for first gear too. From a stop, if I manually shift from 1 up to overdrive it seems alright as long as I don't take my foot off the gas.
I thought it might be my torque converter so when I had my engine rebuilt with a bigger cam I replaced the stock converter with a TCI Saturday Night Special converter with 2000 stall speed. It still does the same thing with the new torque converter. I was told by one person it might be the input sprag. I'm not too knowledgeable on automatic trannys so I'm not sure if he is right. If you have any idea what my problem is and what it involves to fix it because I don't really want to rebuild a tranny that I just put in and I'm kinda short on cash after rebuilding my motor. Also will I hurt the tranny more driving it like this, I put about 6,000 miles on it with this problem, but the problem hasn't gotten any worse. Would a trans-go reprogramming kit or a shift kit help at all. Thanks for your time

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89 Formula 350 Blue with grey interior, 17" ROH ZS wheels, blue BFGoodrich Scorchers, .40 over, Crane roller cam, Hooker Super Comp headers, dual 3" Flowmasters, ported and polished plenum, TCI torque converter, Hypertech Thermomaster, Custom K&N intake

 

I wouldn't say its your "input" sprag (aka foward sprag), instead, I would say its what is splined to part of it, the overrun hub. The purpose of the overrun clutches is to prevent the very thing that is happening in your trans (freewheeling). When you put the tranny is 3rd, 2nd, or 1st, they should apply and give engine braking.

The only way to fix is to remove the tranny, and a shift kit, shift improver, or reprogramming kit, or any other "kit" short of a rebuild "kit" will not fix it.

Does it seem like when something breaks on one persons car, that same part suddenly breaks on a bunch of others? I just had this converstaion the other day in this message board...

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1987 Trans Am 305
14.88 @ 92.81

 

O.K., before you pull the tranny check some things for me. I had the same problem exactly and the governer and two valves were stuck in the valve body. You should try this first as it is free and easy to do. I hope this is your problem too. Good luck!!