th400 governor

[Frank V.]

Is there anyway to locate the original gm part# for a 1971 th400 governor? My transmission shifts smoothly and normally w/part throttle, but at wot shifts to quickly. The detent appears to be working correctly, as you can force a downshift, but only up to 45 mph. The transmission has been rebuilt twice that I know of. The last rebuilder seems to think the wrong governor is in the trans. He can fix it, by changing weights and springs, but claims it will be expensive and time consuming because it is a trial/error process. Or does anybody know of an aftermarket governor that will operate correctly?

[Joe L.]

Re: th400 governor

Is there anyway to locate the original gm part# for a 1971 th400 governor? My transmission shifts smoothly and normally w/part throttle, but at wot shifts to quickly. The detent appears to be working correctly, as you can force a downshift, but only up to 45 mph. The transmission has been rebuilt twice that I know of. The last rebuilder seems to think the wrong governor is in the trans. He can fix it, by changing weights and springs, but claims it will be expensive and time consuming because it is a trial/error process. Or does anybody know of an aftermarket governor that will operate correctly?

Frank------


The original governor was GM #8626844. In September, 1972 this was replaced for SERVICE by GM #8627443. The latter was discontinued without supercession in October, 1991.

[Frank V.]

Re: th400 governor

Thanks so much for the info!
I read on a chevelle forum that pn#8627444 was a "corvette" governor, and that a TriComponent part#34410a was a replacement for that governor.

[Joe L.]

Re: th400 governor

Thanks so much for the info!
I read on a chevelle forum that pn#8627444 was a "corvette" governor, and that a TriComponent part#34410a was a replacement for that governor.

Frank------


GM #8627444 was a governor used for Corvettes as well as some Pontiac GTO's with THM-400. However, as far as Corvettes go, it was applicable only to 1971 with LS-6 and THM-400 and 1973-77 with L-82 and THM-400. So, unless your 1971 just happens to be one of those few equipped with LS-6 and THM-400, a combination as rare as hen's teeth, you require the governor I described in my first post.

[Clem Z.]

Re: th400 governor

Is there anyway to locate the original gm part# for a 1971 th400 governor? My transmission shifts smoothly and normally w/part throttle, but at wot shifts to quickly. The detent appears to be working correctly, as you can force a downshift, but only up to 45 mph. The transmission has been rebuilt twice that I know of. The last rebuilder seems to think the wrong governor is in the trans. He can fix it, by changing weights and springs, but claims it will be expensive and time consuming because it is a trial/error process. Or does anybody know of an aftermarket governor that will operate correctly?

pulling the THM 400 gov. is a easy job as i used to pull them and drill the weights to get full throttle up shifts to come higher in the RPM band.

[Richard G.]

Re: th400 governor

The Governors are easy to find. Ask at your local transmission shop. tell them what you want and they can go through the pile of them they likely have and pick the one with the lightest weights. Inspect the plastic gear for wear and be sure the gear is tight in the governor. Since it only requires four bolts to access go ahead and change it out as is and see if that helps you out any. If you want to modifiy it get the kit with the removal-able axles, for the weithts and go ahead and play with the springs. There are also differences in the valve body springs and the divider plate. These items are selective by application. However the governor spring and weight changes should get you what you want.
Rick

[Joe L.]

Re: th400 governor

Thanks so much for the info!
I read on a chevelle forum that pn#8627444 was a "corvette" governor, and that a TriComponent part#34410a was a replacement for that governor.

Frank-------


How did you make out on this problem?

[Joel A.]

Re: th400 governor

The detent appears to be working correctly, as you can force a downshift, but only up to 45 mph.

The kickdown solenoid("detent") should hold it into a lower gear @wot up to the redline...or more. Having a passing gear work until only 45mph makes me think the solenoid is NOT functioning. You can get a good kickdown/passing gear off of the modulator at lower speeds. If you cannot get a passing gear at say, 60mph, it's a problem with the solenoid, or the control circuit(power/wiring) to it, imho...