1981 Automatic transmission question.

[Gary G.]

Below are pictures of our 1981 C3. We ordered the original build sheet and window sticker from the NCM. I am trying to sort out if I have the original transmission. The car has a VIN of 8803 so it was a late build. The window sticker lists MX1 as the transmission option. Automatic. The build sheet lists MX3 as the option. And the actual transmission has MX2 on the case. We are not able to find any VIN stamp on the transmission at this time. We also found a sticker on the transmission that says Buick on it and appears to be original to the transmission.
Some limited research on line indicates that GM did use the MX2 transmission in some corvettes. Any ideas or input? We believe that car to be original and have several other photos of the transmission. The heat shields are all in place and in correct orientation. It may have been replaced as we do not know the full history of the car. We bought it with 32000 miles on it.
We are in the process of a complete cleaning and restoration of the car. We have the Chassis removed from the body and it has been an adventure so far.
trans1.jpg
trans2.jpg
trans3.jpg
trans4.jpg

Thank you for any input
Gary & Dawn Goodyear
66059

[Tom R.]

Re: 1981 Automatic transmission question.

For some reason, your photos are not legible, the administrators must be playing with how they load but I can't make them out. I have copies of 1980 buildsheets with the MX1 but the buildsheet calls out the MKV. Look in box 5...what's the code there...that's the broadcast code. My copies show 7TW. The MX1/MKV is the sales code while the 7TW is production code...what was installed on the car. I'm also curious what engine was installed...the 305 ci was introduced that year, I believe for California emission requirements.

There should also be a VIN derivative stamped on the transmission if its original to the car. It would be identical to that on the engine stamp pad and reflect the last five digits of the VIN, or the serial number. Sounds like you've searched for it as well. I've linked a worksheet, actually a matching numbers document for my 1978 car. Take a look at the THM 350 stamp.

Send me your buildsheet and window sticker...I'm curious to see what's listed. Send to hunt4cleanair@earthlink.net

http://hunt4cleanair.net/Articles/VIN%209041.pdf

[David H.]

Re: 1981 Automatic transmission question.

... I'm also curious what engine was installed...the 305 ci was introduced that year, I believe for California emission requirements. ...

Tom

That 305 was for 1980 California cars (M4ME computer controlled carburetor). 1981 had a 350 with computer controlled carburetor.

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Gary

That partial VIN stamp might be on the transmission pan.

Dave

[Gary G.]

Re: 1981 Automatic transmission question.

I will have to look today when I get to the shop. Thank you for the information.
There is nothing stamped on the side boss.

[Gary G.]

Re: 1981 Automatic transmission question.

dawnwindowsticke2.pdf
dawnwindowsticker.pdf

[Gary G.]

Re: 1981 Automatic transmission question.

Tom
I sent you an email with the documents atteched. My email is garygoodyear14@gmail.com Might have went to the junk folder.
Thanks
Gary

[Tom R.]

Re: 1981 Automatic transmission question.

We've been able to confirm that the MX2 is original to the 81 car. OP sent a copy of the label that shows both part number and the broadcast code 8JD, which is also on the buildsheet, all of which is confirmation. Also note that the part number is shown on the 81 AIM relevant page. This is guesswork, but I suspect once production moved to BG, broadcast code labels replaced the black stencil, used previously at the St Louis plant.

I might add that the transmission stencils replaced the metal tags familiar to early C4 transmission.

MX2_8JD code_1981.jpg

[Gary G.]

Re: 1981 Automatic transmission question.

81vin2.jpg81trans3.jpg
The attached pictures show what we have been looking for! A huge thank you to Tom Russo for your help and guidance. The VIN is stamped in the OPT V.I.N. location.
The tag that replaced the stencil was located on the left upper portion of the transmission case as shown below. You can see where the tag was located. It did fall off so we have saved it and will be holding on to it. Interesting to note that the tag states Buick on it. The car is a late 81 build.
vin81.jpg