What's the difference between a 700R4 and a T200R4? And how come a T200R4 is a direct bolt in and a T700R4 needs to have the crossmember modified, or do both transmissions need modifications? How big a job is it to install a T200R4? Anyone ever do this swap?

 

Killian, in stock form the 200R4 is generally considered to be the weaker of the two. But when modified to performance specifications both are reported to be equally strong. The 200R4 is the same length as the TH350, Th400, and the Powerglide. The 700R4 is a little longer. The trans mount on the 200R4 is the same as the TH400 making them interchangeable in all aspects except for the yoke must be changed. Changing your Th350 to the 200R4 would reguire you to move your trans crossmember or extend (modify) your mount on the crossmember. Your driveshaft would remain the same. If you switch to a 700R4 you will have to change the trans mount and shorten your driveshaft. The pan area of the 700R4 can also interfer with your exhaust (pan is wider). Of course kits are available for either, or with a little mechanical ability you can make things work on your own. Both require a TV cable to control shift points and shift pressure, so adjustment is crucial to trans performance and trans life. I changed my 75 from a TH400 to a 200R4 as it was the easiest swap for my setup. Even though mine is stock except for a shift kit, I am very satisfied with the outcome. My Vette is a daily driver, hence the need for an overdrive, and I have had no problems. it still performes well. Gather all the info you can about what is available to you and what you want to do or pay someone to do and go from there. This info will get you started thinking and the rest of the decision is up to you. GO FOR IT!!! Hershey :yesnod:

 

Hay thanks Hershey, that was a very informative post. Do you know why the T700R4 is used more often than the T200R4 ? Also, What years came with the T200R4, and what model should I look for to get a donor Trans?


[Modified by killain, 6:09 PM 10/6/2001]

 

The main advantage is if you have low rear gears like 3.70+. 200R4 came in Buick Grand Nationals & Chevy MC SS. 87up preferred.

:cool:

 

Both 200 and 700 are good. When switching from the 400, the 200 is the most direct bolt in. When switching from the 350 its kinda a toss up, allthough I know the custom crossmembers are available for the 350 to 700. The 700 has a lower first gear. What are your gears? The 200 works best when used with steep gears like 3.90 or 4.11. If yur runnin any gear between 3.08 and 3.70 the 700 is usually the better choice. I just completed a swap from 400 to 200. It really changed the car. Now you dont have to be a mainiac to have a little fun. The part throttle first to second gear snatches really make me smile. Im still getting use to it. Well worth the trouble and I would do it again. Heres a link with more info on differences between the two.......http://www.g-body.org/tech/tranny/200_700.html

 

Jvette73, I've been waiting to hear more of how your swap is progressing. Glad to hear it's p and running. We all want to hear all the results. Hershey :cheers:

 

Killian, 200r4came in most 83 and up fullsize Gm products (pont. Buick, and OLds) they also came in BGNs and Monte Carlos and some GM intermediate wagons. Also used in 83 and up Caddies. Early models of both OD trans had problems until the engineers and the aftermarket learned how to make them more reliable and able to hold up to power. Hershey :yesnod:

 

( update th400 to 200r4)
Trannys workin great Hershey. Part throttle upshifts are fast and crisp. Full throttle upshifts are softer but still quick. Chirpin second is a piece of cake and doesnt require a huge throttle load. Full throttle upshifts are comming early at 4000rpm except for shift into 4th. Full throttle 3rd to 4th is delayed beyond 5500rpm. I have to snap the throttle back and floor it again at 5k to shift into 4th at around 100mph. Once in 4th it will hold full throttle without kicking down. I keep my convertor unlocked during these full throttle actions. Ultimatly I would like it to shift up automatically, in all upshifts, at 5000rpm. My TV cable is adjusted correctly so I suppose I may need to get at the govenor to taylor the WOT upshift points.

With convertor locked in 4th on highway im doin 2400rpm@70mph. And thats with a 3.90 rear. I would suppose i could get better highway milage now too but I havnt been able to keep my foot out of it long enough to test that yet. The 3.90's and the lower 1st gear of the 200r are noticably better from the light. The car is hooking good with almost no wheelspin. The front end lifts on launch like never before and stays up there through first and well into second gear. Im sure my 60 foot times will be much better now. I will eventually get it to the track and get some ET results and post them on the forum. I need to practice my manual shifting some more. The new shifter detents are taking time to get used to.