Nickcon78

I just got my new 78 back from shop for check out/ service. I have a TH400 which I know they stopped in 77. My mechanic who worked for a Chevy dealer for 10+ years said it appears that the TH400 looks like it may be original due to the fact that there has not been any modifications to swap it out. The kick down switch is under the gas pedal and looks like all factory wiring.

My question is can it be possible that on the assembly line they had extra TH400's and may have put one in this car? It is an early build, NOV 77. I know it sounds crazy but more than a few people have said it may have happened. How can I identify if this is factory?

It runs great but I am just curious if I may have got a bonus from ST. Louis back in late 77!

Thanks for any ideas!

dar322

Could be. I know my early 78 had a 77 ignition switch. When I swapped it out and ordered a 78, we found out it was a 77. GM probably just used up stock.

Nickcon78

Bump

MelWff

this link explains how the last 6 digits of your VIN should be stamped on the trani

http://www.nastyz28.com/forum/archiv...p/t-21527.html

Nickcon78

Thanks Mel

I was able to get #s off the tag. CA 69 62797 397

Would that mean it was from a '69 ?? I will try to get the #s on the left side as well.

Any other suggestions?

MelWff

based on the link I sent you, yes it is 1969, getting the left side info from the casing and looking at the 6 digit VIN you probably will find it does not match your VIN.

Easy Mike

L-82s, depending upon model year, continued to get the TH400 after the TH350s began to be used on base engine cars.

Nickcon78

Mine is an L48.

hunt4cleanair

Well how come my Nov 10th 77 SA did not get one?

Mel got you on the right track. Get your VIN derivative and that will confirm whether someone did a nice job of installing a TH400 or it was a factory installation.

7T1vette

The TH-350 was a different length than the TH-400, and required a different driveshaft with a different yoke. Once the model year change was made, I doubt that GM would have just let the 'old' build continue just to clear out plant stock. Unused trannies could have been shipped to spares stock or returned to Hydra-Matic for adjusting stock.

Nickcon78

Thanks 7t1vette. That sounds about right.

I am trying to get in contact with the previous owner to get some history about the car. According to the Chevy dealer that took the trade in they have owned the car for the past 15 years.

Hopefully I can get some good info about the car and what has been done to it. Whoever installed the th400 did a good job with it. It looks like it was rebuilt as well.