D2 pinion housing seal 2A3676 - alternate sizing?

that o ring is a very tight fit in my experience as well, I thought i missed abolt as it didn't want to budge when i first attempted to remove the pinion clutch housing.

When i reassembled, i had the hole and the housing very clean by using a wire wheel on a hand grinder to remove any rust and paint. i then used copious amounts of never seize to lube the o ring and the housing to prevent rust formation in the future. it was very tight to re-install, patience and persistance paid off. i was worried about damaging the o-ring but there weren't any sharp edges so it went together well and didn't leak.

the original o ring does come out looking like a square ring from being in place for so many years, i to was surprised when the new one i ordered from cat came as a regular round o-ring.

We've been through this before....
2A-3676 is 6.99mm dia., 85.090mm I.D., 99.070mm O.D.
Option #1
8H2046 (same as a dash 340 trade size) 5.33mm dia., 85.090mm I.D., 95.75 O.D.
Option #2
Cat # 095-1554, 5.7mm dia., 84.60 mm I.D., 96.0mm O.D.

No reason that o-ring has to be so tight.

Thanks! I will procure...

I just received a used pinion assy for my Cat 12 with d318 engine. Also has an old square o-ring. This post was helpful answered my question. I am pretty sure i have the same pinion. Still waiting for a dang parts book from e-bay

The 8T has a different pinion housing but uses the same o-ring seal.

Get yourself a bucket of "Assemblee Goo" It's a transmission assemble lube.

Stuff is amazing for orings. I use it at work. I've struggled with some orings. Tried grease, oil, wd40, brake caliper lube. They all suck, compared to that Assemblee Goo.

http://www.ebay.com/itm/Transmission-Rebuild-Assembly-Lube-Grease-DR-TRANNY-GREEN-Firm-Style-Goo-Gel-/321844744184

A bucket will last you a life time.