Leaking FM146

[rod1625]

Just replaced the FM146 transmission in a 1988 4x4 supercab 2.9L. The old tranny was making bad noises. Did the 4.0L clutch swap. The truck has never driven better.
There's just one minor problem. It leaks fluid around a bolt on the right (passenger) side just below and to the rear of the electrical connector. I thought about removing and sealing the bolt, but I'm afraid something will come loose inside if I do. The transmission had a tag on it that said "fill with ATF". It's of course thinner than the 90 weight that I've always put in them before. Was the tag wrong? Does anybody know if it's safe to remove the bolt and seal it up?

 

[adsm08]

Got pics?

Also ATF + FM trans = bad trans.

 

[Die.Fledermaus]

Uhhh..the transfer case takes ATF only as the norm and is marked so. You really need to supply a picture of what you are talking about.

 

[cavedweller]

One thing that I will say to re-enforce what someone else said ....PULLease Do not use ATF in this transmission!..ATF will kill an FM146 fast,(had to rebuild one when I let someone else service my truck,work schedule ), ....Use ,instead something like Redlines GL4,...not the GL5 or whatever else that is found on your local auto parts suppliers shelves ,for these later mentioned GLs may destroy your synchros...My advice Use ONLY GL4....

 

[xcross]

If the seal is leaking more or less it a bad tranny. Post some pics for a better view of your problem