Thread: any problems i should know about 79 buick trannys?

Originally Posted by 02PrixGT

i bought a 79 buick regal turbo3.8litre what trans is it its auto btw and any problems i should know?

thanks in advance

Originally Posted by Wisconsingrandprix

do u have the 3 speed manual??

Read his post...

Anywho...

It's either the TMH200 or TMH2004R

Not sure about any issues but I found this for ya:

THM200

Right after the 1973 OPEC oil embargo, GM developed a lighter-duty version of the THM350 with lightened materials — primarily alloys in place of ferrous materials (e.g. clutch drums and oil pump). The Turbo-Hydramatic 200 was born; however, this transmission was notorious for its failure rate when used behind a V8 engine — especially the Oldsmobile V8 350 Diesel.
1976 GM vehicles first saw use of the THM200 — from the GM T platform to GM X-Bodies (Chevrolet Nova et al.).
Transmission shops nationwide, along with GM repair facilities, have swapped in THM350s since the 200s were failure prone. Starting with the 1979 model year, vehicles which had the THM200/200C as standard equipment were optioned with the THM250-C, actually a THM350 without the intermediate clutch pack along with an adjustable band similar to the Chevrolet Powerglide.
Around 1979, it received a lockup torque converter, and some internal components (primarily the low/reverse clutch drum and planetary gears) were later shared with the Turbo-Hydramatic 200-4R.
THM200/200Cs were produced until 1987.
The gearing for the 200C is:
First - 2.74:1.0
Second - 1.57:1.0
Third - 1.00:1.0
Reverse - 2.07:1.0

TMH200-4R
In 1980, for the 1981 model year, the 200-4R (sometimes called 200R4) was introduced for use in GM vehicles. Internally, the components which were prone to failure in the THM200 were improved, and this transmission was used with high-power applications — primarily the Buick Grand National and the 1982 Chevy Corvette. GMs powered with the Oldsmobile 5.7 L Diesel powerplant were coupled with the 200-4R in place of the 200. The 200-4R was configured with several different torque converters and gear ratios depending on the vehicle application.
Unlike the 700R4, the 200-4R has a multicase bellhousing for use with Chevrolet, Buick/Olds/Pontiac (BOP), and Cadillac powerplants. Since the external dimensions are similar to the THM-350, 200-4Rs are often swapped in place of THM-350s in older vehicles to provide an overdrive gear. (However, in situations where case clearance and the need for drive shaft modification isn't an issue, the TH400 is more of a close mounting match to the 200-4R. Placement of the mount is identical. The yoke needs to be changed in most circumstances, and the drive shaft length will be different as well.)
Early models had PRND321 on the cluster, while later models had PRN(D)D21, with the left D identified as the overdrive gear by a square or oval ring.
The THM200-4R was phased out after 1990 — its final usage was in the GM B-body lineup (Chevrolet Caprice, Oldsmobile Custom Cruiser station wagon, Cadillac Brougham) coupled to either a Chevrolet 305 or an Oldsmobile 307 engine. It is believed that an HD version of the 200-4R was used in the late 80s Caprice 9C1 police package using the internals from the Buick Grand National