[Dizturbed One]

Seems if I search, I get conflicting answers... Is it ok for me to use gear oil in my NP205 behind my TH350?

It is a frankenstein of parts. The NP205 and it's adapter came from a pre-smog truck in the junkyard, I believe it was a 1-ton with a TH350 swapped in. The transmission is a TH350 pulled from a 2WD 70's pickup (don't know the year never saw it) that had a 4WD tailshaft swapped in (bought on ebay) and the rear housing removed to accommodate the t-case and adapter.

The transmission has been freshly rebuilt, the t-case hasn't though, and leaks like hell, which is why I'd rather use gear oil to move it around temporarily. Seems like it would leak less, and it's cheaper to lose.

In my understanding, these two units are ENTIRELY separate from each other... So, is this safe to do?

[Crosley]

THE 205 T-case uses regular gear oil

If you have a proper adapter, there should be a seal in there that separates the trans oil from the t-case oil

[Dizturbed One]

I do have the proper GM adapter, but I am very nervous about getting gear oil in the freshly rebuilt transmission is all. Many on the K-5 site I frequent simply use ATF in the NP205 to alleviate those fears. However, mine recently started leaking the ATF pretty steadily. Thanks for your reply.

[Crosley]

Originally Posted by Dizturbed One

I do have the proper GM adapter, but I am very nervous about getting gear oil in the freshly rebuilt transmission is all. Many on the K-5 site I frequent simply use ATF in the NP205 to alleviate those fears. However, mine recently started leaking the ATF pretty steadily. Thanks for your reply.

typically the trans oil enters the t-case, not the other way around.

This happens when the seal between the two oils , gets old and hard... trans oil slips by, fills up the t-case.

The gears in the 205 were designed with gear oil. Your t-case, run the oil you wish

[Dizturbed One]

I would rather run it with the design intended. You're right, all the times I've heard of trans fluid filling the t-case, I've never once heard of it vice versa. That makes me feel better actually, because I doubt ATF is hurting a 205, pretty sure I could run mud in it and be ok for a few miles... lol

But oil in the trans had me