I have a 87 GTA with a BADLY rebuilt 700r4(too long of a story to get into), a buddy of a buddy is trying to tell me that a "700R4 out of a 89 Truck/Suburban is far superior to the stock one your car would have had." Is any of this true? I thought that GM only 3 different versions of the 700R4. 1)700r4, base tranny used for full size cars, small trucks and vans 2)700r4, 4x4 trucks, Super Duty/Full size Trucks 3)700r4, found on the Corvette, Iroc, GTA, (basically what GM would call there High performance tranny). Please correct me if I way off here(cuz I probably am), I'm No 700R4 expert.

The later model one should be a little better, I can't remember when they changed the input shaft spline count from 27 to 30. I know the 89 will be a 30 spline. I can't remember if the change was 86 or 89. It should be better then your early one though.

They're all crap and worn out at this point anyway, what difference does it make?

I think the point this guy is making, is that it would be better to rebuild a 89+ 700R4 instead of my 87.

Other then the years, I would like to why would the 89+ be better? I thought the 700R4 that came in the GTA, IROC and Corvette was the best that GM had to offer for automatic transmissions.

the difference, like already mentioned, is after 86 or 87, the input spine count changed from 27 to 30, its the later ones are a little better. But even if the guy has a 89 suburban trans he wants to sell you, (which is why he picked that year, trust me) its still would need a rebuild.

Ah, yes, i forgot to mention that to in my last post......27 to 30 input shaft. And my tranny only had 74 miles on it when it broke.

So if I was to get a aftermarket tranny(direct bolt up), its best to get one with the 30 spline count. Correct? Which would need a matching 30 count torque converter?

http://www.tciauto.com/Products/GM/gm_4L60E.asp

The spline change may have happened in 84, from 27 to 30.

700r4 was upgraded twice during the thirdgen years:
first in 1984 then the input went to 30 spline along
with some mechanical uprades,and again in 1987 when
further mechanical upgrades including an uprated
sprag,as well as a modified valve body and a pump
rotor with more vanes.
I would guess there is no difference between '87 and
'89 700r4s

Thanks guys for all your useful info

The 1989 will have the type 2 valve body, as all 1998 -1993 units will have. The 1987 can have either. The early 1987's have the type 1, and the late 1987's had the type 2. You want the type 2 valve body. The later valve bodies had solved the shift timing problems that the type 1 valve bodies had. If you want to use the type 1 valve body, and have the shift timing problems solved, then install the full TransGo Shift kit (Green and Black box). I have this in the modified version for Heavy Duty use for type 1 valve bodies. The type 1 valve body in a 1987 transmission is the only one that I will not setup for Street/Strip use. For Heavy Duty use, it is fine.

Thanks PBA, thats some good info regrading type 1 and type 2 valve bodies. My GTA was built in May of 87 out of Ohio. Based on your given info, I would believe that my GTA came with the type 2 valve body. The chop shop that did my rebuild, most likely had another 700R4 rebuilt, and ready to go. Keep in mind, that tranny was most likely a base 700R4(out of a full size family car, small van or truck). I'm simply basing this on the MANY problems I've had with it since I got my back from them, and the fact that they STILL haven't been able to correct the shifting problems the 6 times I've returned it to them.

I may try 1 more time, and ask them to put a vette 700R4 88-90 tranny. At least that way it should have the correct springs, servo, and valve body in it, since they obviously DON'T know what model of the 700R4 go's into a GTA/IROC.

Wish me luck, they gave me a 1 year or 10,000km warranty back in the summer of 08. I've since been back there 5 times and put 1200kms from the time of the original repair/rebuild, costing me $1800.