Dana 30a & Chrysler 8.25 Fluid Change

[67Customs]

This is for a 2005 Jeep Liberty.

The owners manual says to use only 75w-140 for the front. The Factory Service Manual says to use 80w-90 for the front.

The owners manual and the Factory Service Manual both say to use 75w-90 or 75w-140 (for towing, which I do) in the rear.

Lots of controversy over using synthetics in diffs. Many claim that conventional is better.

Any reason that I shouldn't use a 85w-140 blend in both? Specifically thinking of Valvoline DuraBlend 85w-140.

In the 60k miles it has been driven, it has seen two changes of Mobil 1 75w-140 in both front and rear. Seemingly no trouble so far. But $80 for me to change diff oil seems goofy when conventional may be better anyway.

Thoughts? Hard data?

 

[zrxkawboy]

In your (warm) climate, that should work fine.

 

[95busa]

Seems like you're changing it mighty often. I would say any good synthetic should take you out to 60K easy, especially for the front diff that really only gets play when you lock in 4WD. That being said I typically run 60K intervals on my gear, swap in a good synthetic usually 75w-140 syn in the back and 75w-90 or 80w90 in the front diffs and call 'er good. I think with as often as you are changing it you could run the cheapest stuff that meets the spec and be just fine.

 

[67Customs]

Originally Posted By: 95busa
Seems like you're changing it mighty often. I would say any good synthetic should take you out to 60K easy, especially for the front diff that really only gets play when you lock in 4WD. That being said I typically run 60K intervals on my gear, swap in a good synthetic usually 75w-140 syn in the back and 75w-90 or 80w90 in the front diffs and call 'er good. I think with as often as you are changing it you could run the cheapest stuff that meets the spec and be just fine.

Manual recommends every 12k. I did it when I got it at 15k and then 30k. I planned on doing it every 30k. Reason why I'm now changing at 60k.

I'm not saying you are wrong or that I don't like your suggestions. Just saying what I have done and what my plans are/were to maybe help others that want to jump in. I definitely thought 15k intervals were way to short. Thanks for the input.

Also, from my understanding, the front diff turns even when not locked, just no load from the transfer, so the oil is still churning. I could be wrong though. That has been known to happen on occasion.

 

[tomcat27]

I'm a long-time dodge/jeep owner and I tow ALOT. I know that Chrysler/Jeep have always called for 12k changes. not sure why. I Put Amsoil 75-90 in My XJ at 20k miles and never looked back. even with off-roading and alot of towing I ran it to 200k with only changing it one more time around 100k.

On my Ram the dealer replaced the gear lube 2X because of a repeat seal failure under warranty. After that, I put Amsoil 75-90 in it when I installed a PowerTrax kit. I Pull a 6000 lb boat thousands of miles each year. It's probably due for a change - it's now at 90k.

as for my liberty's; I too fretted over the book specs and then simply put Amsoil in them. yup - 75-90. I know, what a pattern.

as far as dino vs. synthetic - I've seen some of the debate. But I once overheated the rear end in a Grand Cherokee simply pullling a pontoon boat (alot of wind resistance, I guess) with the factory dino. fluid was coming out of the overflow. so I put amsoil in it and never had a problem again.

 

[caravanmike]

i have an 06 and i am using 75w-90 semi-synthetic in both.

 

[67Customs]

Thanks fellas.