C-3, TH400 oil pan

[D S.]

Does anyone know who sells original TH400 oil pans like the one on my '70? Are they still a dealer item? I went to one Chevrolet dealer and he produced a thin, deep pan version with Turbo 400 Manufactured by GM embossed on it. Wrong! Ebay has piles of chromed, finned, polished, deep dish, thin crust, extra cheesy ones with pimparone, etc.
Thanks for your help.

[Joe L.]

Re: C-3, TH400 oil pan

Scott-----

The oil pan for the THM-400 transmission has changed part numbers many times since 1970. Undoubtedly, each change of part number represents some revision to the pan. The current version which GM catalogues for Corvettes (and, perhaps, others, too) is GM #8679995. That may or may not be what your GM dealer presented you with.

If it is, that's all you can get from GM. For a correct pan, try an automatic transmission shop. Offer to trade them a NEW GM pan for a used but serviceable 1970-correct pan. I'll bet they gladly trade you.

[D S.]

Re: C-3, TH400 oil pan--Thanks, Joe

I was hoping you would respond and I appreciate the part number. I thought seriously about approaching transmission repair shops.

[Jim T.]

Re: C-3, TH400

Scott I replaced the transmission oil pan on my 1970 turbo 400 in May of 1990 with a new one from GM part #8655021. This replacement pan is a great improvement of the original pan because it is a heavier guage metal and really helps in the sealing of the perimeter gasket. Using the recommended torque on the pan bolts does not distort the flange. Wish it was on the 70 when I bought it new.

[Joe L.]

Re: C-3, TH400

Jim-----

GM #8655021 was the immediate predecessor part to the currently available GM #8679995. I don't know how these differ. However, your comment about the improvement in your replacement pan as compared to the original is the "general rule". Usually, when GM replaces a part with another, the replacement represents an IMPROVED part---sometimes it's a later PRODUCTION part which SERVICES older applications and, sometimes, it's just an improved version of a SERVICE part.

Very often, when folks forgo a later part because it's not "correct", they also forgo the functional improvement that comes with the later part. This is REALLY dumb in the case of parts whose configuration can't be discerned when installed on the car, anyway.

[D S.]

Re: C-3, TH400

Re: "This is REALLY dumb in the case of parts whose configuration can't be discerned when installed on the car, anyway."
Looks like I'm caught between a rock and a judging manual. Do I get the correct, original part and lose no points or get a GM service replacement? The one on my car is of a heavy gauge metal as in Jim Trekell's case. Taking your suggestion I did find some like mine at a local salvage yard.

[Joe L.]

Re: C-3, TH400

Scott-----

Well, for parts that CAN be discerned as installed on the car one has to make the judgement of what's more important. That's an individual's own call to make.