Hi! I bought a -88 GTA in september, got to drive it for about a month before I put it in winter storage (Sweden, snowy & salty roads).

I have a problem with the 700r4 though, it upshifts very hard/firm from 1-2 at part throttle, also seems to shift a bit late. It feels kinda like someone rear ends me lightly...

All other shifts seem perfectly fine, and the shift feels good when you're romping it but I guess that's because you want harder shifts the harder you floor it...

I am a mechanic of ~6 years but I have little to no experience with automatic transmissions, mainly because almost all cars in Sweden are manuals so we don't really have to learn how to diagnose an auto tranny.

I don't know the history of the transmission because the guy I bought it from was not a third gen enthusiast (but he didn't neglect the car either). I have tried adjusted the TV Cable (made no difference). Fluid level was too high when I bought it, I've drained some out so it's good now. Fluid looks fine. The problem seems to be at it's worst when it's cold, and it gets better when it's warm but not entirely good.

I have searched around a bit and it seems like a common problem with broken 1-2 accumulator spring.. could that cause my symptoms? Or what do you guys think?

 

The Early 700R4's (87 and earlier) shifted really hard from park-D. Mine still shifts a little hard from 1-2. Is it possible it's an earlier model 700? Maybe it's an early model 88 with that earlier model 700 in it.

 

Check to see if the 1-2 accumulator spring is broken or missing. Have to drop the pan to check. I highly recommend getting a Probuilt shift kit (https://www.700r4l60e.com/store/prod...&cat=65&page=1) if the trans is healthy.

 

Yeah my 86 shifts really hard into drive, an the 1-2 is violent (but my trans was rebuilt with all performance pieces..). Only 87 and up got the part where it cushions the shift into drive from park. Wish I had that!

 

Hmm ok, are there any easy ways to see if i have an early or a late model?

I'm going to drop the pan and change the fluid and filter when I get the car out of the garage in the spring, so then I can check if the spring is broken. Can I buy the spring only or do i have to buy the probuilt kit? Doesn't that kit make the car shift harder/firmer than it originally did? Or does it still feel smooth?

 

I'm not sure if you can buy the spring separately. Dana combines 2 or 3 of the Transgo shift kits so you get get progressively firmer shifts the more you push on the pedal. It's really nice actually. Feathering the throttle it barely feels like its shifting. But once you get on it the shifts are firm and crisp.

 

If a B&M shift kit 'blocker rod' is installed (I think it goes in the line bias valve section of the valve body), the 1-2 shift will be ridiculously hard. I put it in once and had to take it out after a trip around the block. Stupid hard 1-2 shift.

Bill

 

This could also be related to a MAF issue also I believe. I have left a couple of them unplugged, either by accident of diagnosing an notice the 1-2 shift was significantly harder. Mind you these were 90 n up cars so that system maybe different but just an easy thought. And also depending rather or not that fluid got changed regularly, I've heard more than once of cars shifting like crap after all the friction inducing fluid was changed....with not have auto trannys around that maybe something you could read about

 

Sounds weird since the transmission is not computer controlled, but actually I do have a MAF problem, I get code 34 (MAF signal low) sometimes. I'm going to fix it first thing this spring.
I think I have a diagnose already.. Fuel pump relay connector pins are backing out (FP relay also sends power to the MAF relay) and bad fuel pump oil pressure switch so I'm going to replace the switch, FP relay and pigtail. Also going to replace all injectors because I suspect they are leaking (they are original).

 

Mine shifts hard. Always has. Several people have told me it's normal. Doesn't really seem violent, just hard.

 

I haven't driven any other automatic thirdgens before I bought mine so I can't really compare it to other cars like it. I work as a mechanic though and I drive a lot of different cars with autos and It's the hardest shift I've felt in any automatic.
In comparison with my dad's 90's Oldsmobile vans with 4L60E Trannys they shift a lot smoother but maybe they are supposed to shift completely different, I'm comparing a sports coupe to a family van after all...