98 Transmission oil pan gasket

There seems to be two different gaskets available for the 98 tranny. Any way to tell in advance which is which, and why the difference?

The only difference that I know of is the pan capscrew diameter/size. 8mm or 6mm. I would pull one of the capscrews out and measure the shank, then go from there.

I thought it was '99+ 4T65E-HD transmissions only. I know mine is the 6mm shank capscrews. I may be wrong on the years though.

Hope this helps.

Cheers

Straighteight wrote:

There seems to be two different gaskets available for the 98 tranny. Any way to tell in advance which is which, and why the difference?

Can I ask where are you looking that has 2 different possible gasket P/N's for the Trans Pan.
There was only one trans offered and in my searching I have found only one GM P/N for the gasket.
In the aftermarket world there will be 2 gaskets, but, that is only because one is a paper type and the other more closely matches the OEM which is made up of a metal sheet for a core and has rubber bonded to both sides. The OEM or OEM replacement is a re-usable gasket and is much better at sealing leaks.
I found the good OEM type available at NAPA, although you must be specific when asking for a gasket because they also sell a paper type (cheaper). There computer does have remarks in it that mentions the more expensive gasket is metal with bonded rubber.
HTH,
Rick

Buick dealer told me there were two and he only had one of the two. Soooo of course I tried to diferentiate to determine which one I needed before tearing the old one apart.