my head and eyes hurt looking at transmission lube

[dkeven]

Been reading and reading, some purist say only use what the govt. spec'd for the transmission, others say times and lube have changed use latest and greatest synthetic, others say synthetics ruined transmission shortly, still others say use any gl5 mt-1 rated and everything is peachy. wieight is either 50w engine oil 90 wt gear 75-90 or 85-140. Well what is it, who has an original transmission with with a bunch of miles and has accomplished this by using what exclusively. On another note many thanks to m-35 tom and m16ty for their parts and knowledge as my deuce now has a 5th gear again. How hot do these transmissions get anyway? seems pretty warm after a 55mph jaunt.

 

[combat32]

When I was in the Army we used any 90wt we had on hand, I run 90wt in mine, couple thousand miles and no problems.

 

[wsucougarx]

I run GL-1 90

 

[m16ty]

I run GL-1 90

It's hard to go wrong with the what the military calls for. My local CO-OP is the only place that keeps it in stock (alot of old tractors call for GL-1).

On the heat issue, I've noticed they get pretty warm. I don't think it's so much the trans making the heat as it is the heat from the engine getting blown back onto the trans.

Glad to hear you got your truck back going.

 

[Tinwoodsman]

I pondered this subject for the longest time and decided to go Lucas 80/90. Good luck with your choice.

 

[RAYZER]

gl1 from napa, $44.95 per 5 gal. the best thing to use!

 

[bratpackdad]

GL-1 here, I ran it out to Anza Borrego (hot, dry, big hills) during the summer heat. No issues running in 100+ heat and long hill climbs.

 

[JasonS]

50wt oil is what the transmission designer specified. Use what you want.

 

[dkeven]

just when i thought it would be simple another user points out the original spec. I know 50 wt motor oil roughly crosses to 90 wt gear after reading extensive posts on the subject and have read of it being possibly relabeled as in smittys super syn 50. Around here in Chapel Hill have yet to find GL1 or 50wt all coops and auto parts stock 80-90 ep gear oil only

 

[JasonS]

just when i thought it would be simple another user points out the original spec. I know 50 wt motor oil roughly crosses to 90 wt gear after reading extensive posts on the subject and have read of it being possibly relabeled as in smittys super syn 50. Around here in Chapel Hill have yet to find GL1 or 50wt all coops and auto parts stock 80-90 ep gear oil only

Try a local big truck shop; ours had it on the shelf in the showroom. Either way, don't lose sleep about it. I doubt that the military would use 90wt if it was severely detrimental to the transmission life.

 

[dkeven]

looks like napa 65-205 fits the bill will be getting some of that in wanted to do a flush after putting trans back together and running an little while

 

[tm america]

syntetics have their place...but using them in transmissions not designed for it will give you shifting problems and cause you lots of problems. the syncros need to be able to grab the gear to speed it up in order to make everything line up . if the fuild is to slick like syntetic the gear won't get up to speed and you will have hard shifts .This willl beat up on the engaging teeth ..thus short life for the trans..

 

[Crazyguyla]

I know some modern oils are not yellow metal safe i.e. brass parts. From what I remember from reading through all those posts posted all through the forum, the oil must at least be safe for brass parts or the transmission syncros will have a very short life.

 

[dkeven]

has the GL1 from NAPA in it now used 85-90 as a first run and flush to get out any little bits I left from the reassembly, shifts good, pretty quiet still wonder how hot it will get in the long run. May drive for a while and shoot the case with the ir just to see

 

[two.fiveM35]

I know what you mean. It's hard to get a straight answer. In my lub order (Apr 83) it says to use MIL-L-2105 rated oil. I didn't see that on the GL- 1 oil. GL-5 had it and check out the last post on this thread (Another gear lube oil thread ), it is helpful. I have not changed mine yet, but I'll go with the GL-5 and Lucas additive. 50/50

 

[dkeven]

not sure of the lucas additive yet some of the well thought out posts indicated the possibility of the older oil containment system failing with the climbing gear action of the additives, my first thought that reverse thread on the input shat without any seal, lucas on the clutch would suck for sure.

 

[unclemikey]

IT'S ALL SO CONFUSING.........I tell you in truth, the single hardest thing I have ever done in working on the Deuce, is finding the right BLOODLY Trans Oil . Every time I think I have got it down right, someone comes up with a new post that makes me question that choice . Heat, Grab, Lube, Yellow Metal,........ sometimes it makes me wish I had an A3, (well, maybe not an A3 ).

I can't tell you guys how much I learn and value your knowledge on everything Deuce.


But one this one thing.............

Unclemikey

 

[Crazyguyla]

IT'S ALL SO CONFUSING.........I tell you in truth, the single hardest thing I have ever done in working on the Deuce, is finding the right BLOODLY Trans Oil . Every time I think I have got it down right, someone comes up with a new post that makes me question that choice . Heat, Grab, Lube, Yellow Metal,........ sometimes it makes me wish I had an A3, (well, maybe not an A3 ).

I can't tell you guys how much I learn and value your knowledge on everything Deuce.


But one this one thing.............

Unclemikey

I feel your pain on this issue. When it seems like the whole issue about trans gear oil is said and done, something stirs up the hornets nest. LOL I still have yet to change the oil in my transmission, it's low on the list of thing to do. I have to get it running again.



3 times a charm

 

[JasonS]

There is nothing to be confused about. 50wt oil is common and available. Go to a shop that services larger trucks.

 

[bratpackdad]