Synthetic differential oil too slipery??

[ranger]

Hi folks,

As most of you know, we have a wet-clutch rear posi unit.

Years ago, when running a 9" Ford Traction Lok, I changed to synthetic gear oil. This was pretty "high-tech" for the time--1972.

I lost the posi!!

Turns out that the oil was so slippery that the wet clutches just slipped against each other, completely, and never grabbed.

Took the posi apart and installed new clutches and conventional gear oil.

Now, I know our posi units are not exactly the same as the Ford Traction Lok, as I believe that ours need to hit a certain r.p.m before the clutches lock, but I am wondering if we should avoid synthetic gear oil??

It would be nice to use, front and rear, as we could probably pick up a little extra m.p.g. Of course, no worry with the front (non-posi) differential.

Opinions?

Best,

Ranger
Aiken, SC
Sy 1563
12.71@106.42@18 lbs.

 

[ajt86]

Re: Synthetic differential oil too slipery??

Use sythetic with posi friction modifier additive

 

[atkonkler]

Re: Synthetic differential oil too slipery??

I use 75w140 syn with additives

 

[warmpancakes]

Re: Synthetic differential oil too slipery??

Who is we? Factory is a gov lock ratcheting

 

[DaveP]

Re: Synthetic differential oil too slipery??

Factory is a gov lock ratcheting

You make it sound like it functions like a Detroit Locker.

 

[Beavis]

Re: Synthetic differential oil too slipery??

I put Royal Purple in my diffs (front and rear) about 8 years ago, havent had any issues and the posi-gov-lock still works fine.

 

[midnightbluS10]

Re: Synthetic differential oil too slipery??

I put Royal Purple in my diffs (front and rear) about 8 years ago, havent had any issues and the posi-gov-lock still works fine.

I've been hearing a lot of bad things about royal purple lately. Like that their oil is full of molybdenum and thats why they have to tint it purple...to hide it.

 

[sy2585]

Re: Synthetic differential oil too slipery??

I just changed to royal purple engine oil, less than 100 miles on oil change. please don't tell me to get it out?

 

[warmpancakes]

Re: Synthetic differential oil too slipery??

You make it sound like it functions like a Detroit Locker. It doesn't.

The gov-lock still has clutch packs, similar to a Positraction. The method of application of the clutches is different, but it is definitely not a ratchet-er. (Which has no clutch frictions).

The recommended lube is GL5, 80W-90. I've had 'issues' with using lubes other than the GM P/N 1052271. So that's all I have put in a gov-lock rear for about 15 years. The friction modifier / additive is NOT specified as required for the gov-locks by GM. So don't use it.

sorry, I should have been more clear, I was saying our diffs dont require modifier or "whale sperm"

 

[hatrik8]

Re: Synthetic differential oil too slipery??

I just changed to royal purple engine oil, less than 100 miles on oil change. please don't tell me to get it out?

I think this is specific to differential. I've had royal purple in my truck for a long time now with no issues. I plan on using royal purple at my next oil change too

 

[ranger]

Re: Synthetic differential oil too slipery??

At Dave P.,

As a mechanic for 40 years, and one who learns every single day, just wondering what kind of "issues" you have had with non-GM lube??

Thanks.

Best,

Ranger
Aiken, SC

Sy 1563
12.71@106.42@18 lbs.

 

[Gnocide]

Re: Synthetic differential oil too slipery??

synthetic is fine.
stick with the right weight.

dont worry about posi additive -
the GEARS will TELL you if you need to add the bottle!!
(FIRST BY VISUAL INSPECTION WHEN THE COVER IS OFF THE REAR, 2nd by the wonderful sound of mesh and chatter if its needed.

 

[5678TA]

Re: Synthetic differential oil too slipery??

synthetic is fine.
stick with the right weight.

dont worry about posi additive -
the GEARS will TELL you if you need to add the bottle!!
(FIRST BY VISUAL INSPECTION WHEN THE COVER IS OFF THE REAR, 2nd by the wonderful sound of mesh and chatter if its needed.

X2. i just threw in a TRD limited slip in my tacoma with plain ole 75w90. people said to throw in the friction modifier or it will chatter/jerk. she's running smooth without it... had i thrown the friction modifier in, it would have made the lube even more slippery and cause unwanted slip in the clutches. Only use as much friction modifier as needed.

 

[DaveP]

Re: Synthetic differential oil too slipery??

I had trouble with two different differentials.