: 4.1lt Needs A New Box

01-04-11, 09:12 PM
Hi, I've got a RWD 84 Sedan Deville that has just had $4000+ spent on rebuilding the engine(HT 4100). Drove the car for 3 months only to have the tranny crap itself(THM 200-4r). Was quoted $3000 minimum to rebuild it to new.

What my question is, is there another box that will bolt up to this engine, olds, chevy etc? We have plenty of THM 350, 400, 700 and Oldsmobile boxes etc here in Australia, just no Caddy boxes. Thanks for any help.

01-04-11, 09:53 PM
Put a rebuilt 700 in there and you wont have to worry about it again. Then again, a rebuilt 200 will probably last for the rest of the cars life also. Use a bolt pattern adapter to put the 700 in.

01-04-11, 10:04 PM
I never liked the 200 4R transmission much after having many of them go bad on me.. If you were going to put a different transmission you would lose the overdrive... you could bolt in a TH400, they did make what we call a BOP bellhousing... that fit Buick,oldsmobile and pontiac... it also fits Cadillac.. If you can find a 1977 to 1981 th400 cadillac trans it will bolt in and I think the driveshaft will fit your car ...Can't you find a junkyard 200 4r transmission ?

01-04-11, 10:19 PM
The THM-200 isn't Cadillac specific. It was used in most GM rear wheel drives during the 80's, usually paired with the Oldsmobile 307 (an engine that would have easily replaced your 4100). The TH 400 and 350 were three-speed transmissions, which will kill any fuel economy you had and possibly damage the engine if you do a lot of highway driving. The THM-700 is a Chevrolet four-speed, which has similar gear ratios to the 200. As stated above, to use the 700, you will need a Chevy to BOP (Buick, Olds, Pontiac) bell-housing adapter.

But if at all possible, try to find a THM-200; it is less complicated to install and if anything will make spending that $4000 more worthwhile (as an effort to keep everything original.) The THM-200 was used behind the Buick 231, the Pontiac 301, the Cadillac 4100, the Oldsmobile 307, and the Oldsmobile 350 diesel. Some of the Chevrolet 305's and 267's also came with the 200, connected through a multi-fit bell housing. Here is a list of vehicles that used the THM 200 transmission:

1981-'88 Buick LeSabre and Electra RWD
1981 Buick Century
1981-'87 Buick Regal/Grand National
1982-'90 Cadillac (Fleetwood) Brougham
1982-'84 Cadillac de Ville
1982-'90 Chevrolet Impala and Caprice
1981-'88 Chevelle, Monte Carlo, Malibu and El Camino
1984-'87 GMC Caballero
1982-'90 Olds Delta 88, 98 and Custom Cruiser
1983-'88 Olds Cutlass 4-4-2 and Supreme
1983-'89 Pontiac Bonneville, Parisienne and Safari Wagon
1981 Pontiac Firebird with 301
1984-'87 Pontiac Grand Prix

01-05-11, 01:46 AM
Didnt the TH350 have overdrive?

01-05-11, 01:52 AM
Shouldn't have too much of a problem getting one, we have plenty of 700's over here, they came out on nearly every 6 cyl Holden since about 1988. Will look into the bolt pattern adaptor. Thanks

01-05-11, 02:51 AM
Didnt the TH350 have overdrive?

No. The 200 was the first Turbo-Hydromatic to have overdrive.