T-case fluid confusion

[crazy4offroad]

A lot of you know I'm having trouble with the front driveshaft spinning in my truck while in 2WD since converting to TH350. Tore it apart today and saw nothing askew. Pondered it being blamed on a bad locking hub, but remembered seeing the front output yoke spin while parked in 2WD with the rear d-shaft out so that's kinda debunked. Only other thing I can think of would be the weight of the gear oil. I know it had gear oil in it when I drained it but that doesn't mean the last guy knew what he was doing.

I googled it a while and found some people said ONLY run 80W-90 gear oil, other people said ATF for 205 behind an auto, and read another guy who said his Chilton manual calls for ATF in an NP205 behind an automatic trans, gear oil behind the SM465. Then the next post he got trashed (guess which forum) because someone else's Haynes manual said gear oil only, arguing gear oil for gear-to-gear t-cases, ATF for 208's, 241's etc and motor oil for the 203. SOOOO, thoroughly confused at this point, I wanted to see what some of you guys recommend. I began to wonder if the heavier weight oil would be enough to make that shaft spin, but you can stop it from spinning by hand.

 

[bucket]

It's my understanding that the later "syncro" 205's ran ATF. I do not know what year that started or if it was for behind automatics only. I just know it was available at some point because auto hubs were available on the K30's too.

 

[sean1960]

I run 80W-90 gear oil in a divorced 205 and the front driveshaft spins in two wheel drive. I'm assuming the gear oil is the cause of this phenomena.

 

[crazy4offroad]

Thanks guys, I had read it was OK to run ATF, that many people do it, and read just as many posts that said NOT to run it, that gear-to-gear t-cases require heavy gear oil. I like running gear oil better, I just need to get my front driveshaft figured out so it's not so noisy. You know women, every little sound in an old truck they say "what's that noise??" no matter how many times you tell them wtf it is!

 

[oneluckypops]

I always ran 50 weight in my 205 in my 79' Driveshaft didn't spin in 2wd. That truck also had the sm465 in it, if that helps any.

 

[hootsmcgoots]

In the Army we always ran atf in the humvee's nvg242. I have yet to check mine since Ive only had it a couple weeks. I guess I.should get on that.

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