Trans fluid leaking to TC

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OBS Enthusiast
Sep 19, 2017
Reaction score
coral springs FL
Hello Guys.
just finished installing a crate engine in my truck after 4 years of seating in the driveway.
when I started the job, I noticed a fluid leak under the transfer case, so I removed it and resealed it.
before removing the TC and before draining it, I opened the filler plug, and a significant amount of fluid came out (unfortunately I didn't measure it). I didn't give it much thought.
after installing it back on the truck I filled it with 1.3 liters of transmission fluid as instructed in the workshop manual.
I checked the level of the transmission fluid and it was empty. I needed more than 5 quarts to fill it up. so the transmission was dry.
the transmission was rebuilt about 500 miles before the old engine died and the truck was parked.
no leaks from the transmission or transfer case at the moment, but the transmission is losing fluid.
I drove the truck for about 50 miles since I finished the truck and check the transfer case fluid level this weekend.
sure enough, 1/2 quart of fluid came out of the filler hole (this time I measured). so there is definitely a fluid leak from the transmission to the TC.
the question I have is regarding the seals.
I'm probably going to drop the TC again and replace the input shaft seal (and all other seals), but was wondering if there is another one I should worry about on the transmission side.
the truck is 89 K1500 with 700R4 transmission and 241C transfer case.
Thanks in advance.