Topic: differential additives

[zowtiak]

hey all! I just drained my front and rear diffes on the 95 yj with automatic transmission. Some one i work with said i should add an additive to the fluid. i looked in the haynmes manual and in the FAQ. I may have missed it, but does anyone know about this?

[Torch_Ind]

if your open diff it's not required. typical gear oil the call for is fine.  if you want to use better fluid pick up a synthetic gear oil.  that's about all I use

[aparke4]

yes to the above: syn gear oil cuts down on friction and tends to stand up better to towing, higher RPM, etc. My DD tj has front and rear aussie lockers with syn diff oil and it really quiets them down. Before the lockers I changed the oil over to syn every oil change or every trail ride involving mud or water and shifting was somewhat smoother and what I would call happier. Most people see better driving and shifting results by using a synthetic gear oil. Friction modifiers are only needed again for a limited slip, etc due to the clutches inside that need the extra help. All my jeeps with lockers (aussies, arb and detroit) run best with a syn gear oil Our 4 bangers need all the help we can give em'! Well worth the cost.

*4 oz of friction modifier is required with Trac-Lok limited slip differential.
**Friction modifier is NOT required with Tru-Lok locker/limited slip differential (factory Rubicon locker).

75W-90 is what you should use. 75 correlates to the weight. Here is some info I found on a quick search.

from some other sites:

Fluid Capacities:
http://www.jeepforum.com/forum/f9/faq-fluid-capacities-489932/



Synthetic oil was originally developed for applications for aircraft and military as a superior replacement to conventional oil. Synthetic oil can resist higher temperature before breaking-down which translates into superior lubrication and possibly extended drain intervals. I firmly believe the benefits of synthetic oil outweigh the higher costs.

common brands your parts house might carry are royal purple, mobil 1 and valvoline synthetics. I have used all brands with success.

[zowtiak]

Thanks for the reply. It sounds like syn is the way to go.

[aparke4]

for sure - I also went went Lube Lockers which are the reusable diff gaskets which eliminate RTV. I have used them for the last 3 years with zero issues. Less mess = success b/c diff gear oil sttttiiiinnnkkkkkkkkkkksss!!

[FourbangerYJ]

b/c diff gear oil sttttiiiinnnkkkkkkkkkkksss!!

It's kinda like a manly perfume! 

[chrisfranklin]

yes to the above: syn gear oil cuts down on friction and tends to stand up better to towing, higher RPM, etc. My DD tj has front and rear aussie lockers with syn diff oil and it really quiets them down. Before the lockers I changed the oil over to syn every oil change or every trail ride involving mud or water and shifting was somewhat smoother and what I would call happier. Most people see better driving and shifting results by using a synthetic gear oil. Friction modifiers are only needed again for a limited slip, etc due to the clutches inside that need the extra help. All my jeeps with lockers (aussies, arb and detroit) run best with a syn gear oil Our 4 bangers need all the help we can give em'! Well worth the cost.

*4 oz of friction modifier is required with Trac-Lok limited slip differential.
**Friction modifier is NOT required with Tru-Lok locker/limited slip differential (factory Rubicon locker).

75W-90 is what you should use. 75 correlates to the weight. Here is some info I found on a quick search.

from some other sites:

Fluid Capacities:
http://www.jeepforum.com/forum/f9/faq-fluid-capacities-489932/



Synthetic oil was originally developed for applications for aircraft and military as a superior replacement to conventional oil. Synthetic oil can resist higher temperature before breaking-down which translates into superior lubrication and possibly extended drain intervals. I firmly believe the benefits of synthetic oil outweigh the higher costs.

common brands your parts house might carry are royal purple, mobil 1 and valvoline synthetics. I have used all brands with success.

I've been using mobile synthetic for about 9 years in both diffs and I've had an Aussie in the front for about 5 years, still using synthetic, and I don't think I've ever heard the least bit of noise from the Aussie in 2 or 4wd.    Not really scientific test or anything -- I've never used an Aussie without synthetic -- but I'd guess that synthetic probably helps all lunchbox lockers in terms of noise/smoothness (and I like my Aussie lunchbox despite all the ARB/OX/Detroit snobs here  kidding

[FourbangerYJ]

(and I like my Aussie lunchbox despite all the ARB/OX/Detroit snobs here  kidding

I'd run one in the front but, no way in the rear again. BTDT no thanks to much noise and clunking! Plus your depending on the stock carrier to last.

[TrailsLessTaken]

Im using the Amsoil severe gear in mine vehicles and like it, It seems to do pretty well with the towing

[chrisfranklin]

I'd run one in the front but, no way in the rear again. BTDT no thanks to much noise and clunking! Plus your depending on the stock carrier to last.

FourBangerYJ were you using an Aussie and synthetic in the rear end?  I'm just wanted to hear opinions as to whether synthetic gear oil makes a difference or not noise-wise with Aussies in the rear.  Not planning to put one in my D35 but I wouldn't necessarily be averse to putting one in an 8.8 swap if there was a way to keep it quiet.  If not, I'll just go driver-adjustable.   

[FourbangerYJ]

FourBangerYJ were you using an Aussie and synthetic in the rear end?  I'm just wanted to hear opinions as to whether synthetic gear oil makes a difference or not noise-wise with Aussies in the rear.  Not planning to put one in my D35 but I wouldn't necessarily be averse to putting one in an 8.8 swap if there was a way to keep it quiet.  If not, I'll just go driver-adjustable.   

It was a Lockrite. It's been many years so I am not real clear on the fluids used. More than likely it was just plain old Dino, not synthetic.
I have been running M1 90-140 in the rear for a few years and like it (Detroit). Before that was M1 75-90. Did a good job but from what I understand the heavier oil does a better job at protecting the gears.
From what I understand the synthetics do a better job keeping things quite with the lunchbox style lockers. I would imagine with the Detroit too. When I broke in my gears I ran plain old gear oil. Then switched to synthetics to be honest I don't remember any changes in noise or handling or the normal Detroit personality. 

[aparke4]

upon going to synthetic - my front locker would "chirp" - aussie - and since then it you can barely hear it... heck my old girlfriend did not even notice it! I have a detroit in the rear as well (full locker) and the syn really helped keep it right - well worth the money even if you do ride a lot/ change oil a lot