thm200 or 700r4 87 Cutlass Supreme

Status
Not open for further replies.

soba_03

Not-quite-so-new-guy
Nov 28, 2008
33
0
0
Louisville Kentucky
OK I did the search on the site but really didn't answer my questions.

The trans in the car with 40,000 is thm200 confirmed by RPO code. So it's a 3 speed. It acts up at low speed when on and off the throttle. I'm not sure what that is all about.

I have a 700r4 out of 86 vette, simple questions I have yet to answer.
1) Will the 700 bolt up to the olds 307 in the car? I'm thinking probally not.
2) With 2.14 rear end that is in the car is there any benifit to the additional 4th gear?
3) Can I use the console shifter for a 3 speed for a 4 speed install? Is it nothing more than adjustment and new 4 speed indicator plate.
4) Crossmember for the thm200 and 700r4 different? Length, driveshaft length.
5) 700r4 or should I find a 200r4 is there any difference? It's a stock 307.
6) Could the whole shifting/shuttering problem be TV cable out of rig?

Thanks,
Mark
 

apj87442

Not-quite-so-new-guy
Feb 12, 2009
14
0
0
NewJersey
The 700 will fit with an adapter plate from here or maybe summitracing or jegs http://www.compperformancegroupstores.c ... ode=230001. The crossmember from a 200r4 should work. I don't know about the cable as to which will work. Your driveshaft definately needs to be shortened.
A tv cable out of adjustment can cause problems. The TCC system may also have an issue. You can start by disconnecting the blue or white connector on the left side of the transmission...Then drive to see if your symptom still persists.
 

KrisW

G-Body Guru
Oct 24, 2007
582
8
0
Lakeland, FL
Okay, here is what I have dealt with in the past.

An 87 Cutlass SHOULD have a second set of mount holes on the frame for the transmission crossmember to slide back to the next set of holes. Many 81-87 cars have these holes, some do not. If you have them you just need to slide the crossmember back to that next set.

Once the crossmember is back, if you use a 2004r, EVERYTHING is a direct swap (even the TV cable) and NOTHING else has to be changed, not even the driveshaft. Your shifter will still work but the positions will be all wrong as soon as you pull it out of park. Eventually you will need a 4 speed factory shifter or an aftermarket shifter for your console.

Using a 700r4 you can do much of the swap easily, but the transmission lines are a bit off and have to be bent a little, you need a different torque converter (that costs money,) and you still have to move the crossmember. You will also need an engine adapter plate which will cost anywhere from 50-100 bucks easily.

YES with 2.14 rear gears you will benefit from your new transmission! Not so much from the 4th gear, but from 1st gear! Your car will take off like you put a different engine in it if you do the swap.

Personally, I would recommend selling your 700r4 and buying a Grand National spec 2004r to make the swap easier and with less hassles. After that, you definitely need to upgrade to a 3.50-ish rear gear ratio.
 
Status
Not open for further replies.

GBodyForum is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to amazon.com. Amazon, the Amazon logo, AmazonSupply, and the AmazonSupply logo are trademarks of Amazon.com, Inc. or its affiliates.

Please support GBodyForum Sponsors

Classic Truck Consoles Dixie Restoration Depot UMI Performance

Contact [email protected] for info on becoming a sponsor