Gear lube question

[brownz]

I have a moser 12 bolt with a tru trac. I called eaton on a noise issue that I have and they told me to get some shell spyrax 91 40 gear oil. I cant find it local.

I have 80w-90 in it now what would be a good oil to run that is thicker? 85w-140?

Thanks

[JEFFTATE]

Did they say 90 -140 ?? ( Not 91-40 ) ??

[brownz]

haha yes thats it. would that be a good lube to run?

[dontlifttoshift]

Yep, my rearend dude recommends 85-140 as well. Not synthetic though....

[brownz]

Yep, my rearend dude recommends 85-140 as well. Not synthetic though....

yeah they said DO NOT use synthetic. so im going to switch it over tomorrow and see what happens. I hope it helps...

[TheJDMan]

Did they say 90 -140 ?? ( Not 91-40 ) ??

That's funny!

[rrelco]

coast driveline in Ventura cali told me not to ever use synthetic but i didnt listen....I am using AMSOIL the best lubricants my opion! acually my whole drive train is AMSOIL and no issues at all, and I dont drive my car I abuse it.....

[sam 74]

i'm useing royal purple 85-140 with my Detroit locker, i've always used synthetic oil in the rear and never had an issue.

[BuzzKillian]

I think I'm having a Posi clutch sticking issue. I used the Richmond 85-140w synthetic. Which is supposed to be for limited slip differentials and what the gear Mfg. recomended. It works fine when its cold, but after 20-30 min. driving, it pops when I turn.(feels like sticking cluthes to me) I tried adding friction modifier, but it didn't help.

I am not 100% Who made my posi unit. The previous owner said it was a Strange Posi with Strange Axles. So far I have been unsuccessful in finding installation or tech. info on their site

I was checking out Eaton's web site, and noticed they don't recomend synthetic lube. SO, my qustion is... If I drain the synthetic out and replace it with conventional lube, do you think the sticking might go away? Or Are the cltuches ruined and have to be replaced?

[badazz81z28]

After $600 for a posi unit...I listened to Eaton...No synthetic here and I have no noises what so ever.

[sam 74]

i use royal purple 85/140 in the rear with a detroit locker.

[Rod]

Brad Penn Gear oil 80-140 the best I have used

[BuzzKillian]

Have any of you,used synthetic... had a problem... switched to conventional and the problem went away?

[BBPanel]

Currie will not honor warranty on my Tru-Trac if I run a synthetic - considering some Schaeffer's 80W-140 Moly

I ended up buying Currie's gear lube fr their website - tired of going all over town looking for stuff.

[AmKenpo1]

Strange Engineering recommends the use of 85-140 non-synthetic gear lube, friction modifiers are required for all clutch type posi units. Our complete assemblies are always supplied with Lucas 85-140 Heavy Duty non-synthetic gear lube.
We have seen no adverse reaction in switching from synthetic to non-synthetic in our test cars.

Wil.

[JEFFTATE]

I have an Eaton , old school , clutch type, limited-slip posi-traction differential in my Camaro.
I use Torco 85-140 RGO .
I bought it form Lane Automotive / Motor State Distributing in Michigan .
It is not synthetic .
I also use a bottle of GM limited slip additive .
I've never had any problems , chatter or failure in the rearend .

[BuzzKillian]

Thanks for the responses. I am going to try changing the lube to non-synthetic and see what happens.

Hopfully the weather breaks soon. I won't drive the car in the Slush abd Salt so it might be a little while until I post the results. (I can't be the only one that has had this problem).

[badazz81z28]

If I was going to guess...Synthetic has better lubrication properties thus allowing the clutch packs to slip easier due to less friction holding the packs together. This would lead to accelerated wear of the clutches causing a decrease in performance.

As for Tru-tracs and Lockers...Doesn't make any sense to me.

[BuzzKillian]

OK... It has been a couple months and 3000 miles since I changed to Lucas 85w-140w Heavy Duty non-synthetic gear lube with GM friction modifier. The clutches don't appear to be sticking as bad as they were and it is quieter now.

While I had the cover off, I changed out the C-Clip Eliminator kit to the tapered version. I hope this helps someone else, if this problem comes up again.