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Chevy Conversion Issues

324 Views 3 Replies 1 Participant Last post by  **DONOTDELETE**
Howdy. I have a friend wo is bringing his jeep over to do some work and I am not sure that he is right. He has a CJ7 with a chevy 350/Turbo 350 and 205 x-fer. He is leaking tranny fluid out of the rear seal of the transfercase. I thought that the x-fer should have motor oil in it, but he says its auto tranny fluid. I have never messed with anything cept Jeep, so any input would be great.

Thanks in Advance,

66 CJ-6A Tuxedo Park
78 CJ-5 Levi's (soon to be running)
96 XJ 2WD (grocery getter)
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Every 205 T/C I have dealt with has used gear oil. If your friend put in ATF that could be why it is leaking. ATF is
much thinner than gear oil which would allow it to get past the seal much easier. Check a repair manual for the
year of the T/C it will tell you what you are supposed to have in there.

There was a good size discussion on the Chevy board about this. Basically they came with ATF from the factory in cold climates. The leaking you talk about has been experienced before by a few people. The ATF is thinnner and will leak out of a marginal seal whereas the gear oil is heavier and won't. A plus to this is there won't be any cross contamination between the tranny and transfer if the seal is gone between the two.

I run gear oil in mine, does fine. I have even seen an SM465 tranny with ATF in it (6 oz, supposed to be 4.2 qts, do search, amazing it worked) from the factory. There were lots of vehicles with combinations like this from the factory as well. He can try and run gear oil in it, just drain the ATF, fill with gear oil, run for 50-100 miles, drain and refill with gear oil. It's a stout transfer, neither will hurt it, but I've heard there is more power loss using the gear oil than the ATF due to the viscosity difference (fluidic drag, makes sense). IMHO I bet you couldn't tell the difference.

'81 CJ-8 Scrambled!
GM151/SM465/NP205 twinstick/7"Lift/33"TSL's/IHC D44's 4.10's Lock'd
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My np231 has ATF in it. Most of the newer trucks all run ATF.

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