THOUGHTS ON WHAT I DID!

[BISCUT]

I'm running a 2004 F-150 4x4. 60k miles I changed the reear differential fluid. Fluid looked ok no metal chips no signs of moisture. Gears looked good as well. I installed a new PML oversize cover (magnetic drain plug!!). Filled with Mobil 1.

The front cover looked more of a PITA so I had a friend who is a mechanic change that gear oil for me. I went with Lucas Synthetic in the front differential. Same deal, no metal chips or signs of moisture.

How often are you guys changing your differential fluids?

And mine is a limited slip so I do have to add the friction modifier.

Thanks for the replies.

 

[law3500]

I just changed the diffs and tcase on my Expedition yesterday. I used Amsoil fluids and I like to change them out every 50k miles. It may be overkill but I like pulling out clean fluid with no metal.

 

[exranger06]

I believe Mobil 1 already has friction modifier mixed in, so you probably didn't have to add any more. I would change it about every 50k.

 

[charbaby]

I can't answer for the Lucas fluid but I beleive that the Mobil 1 has the LSD friction midifier already in their fluid.

As-far-as how often to change the F/R diff fluids (and don't forget the TC fluid) all depends on how the truck is used. If the truck is only used as a daily drover(DD) then every 60K miles would seem OK!

Others will chime in with more question about the truck usage etc.

 

[Astro14]

50K is a reasonable number for a street-driven truck...depends on use...I change mine on the 4 Runner far more often than that...but I frequently drive through salt water...deep salt water...up to the axles (you should see the rust on the poor thing...).

 

[Artem]

Read the Manual. That would be my best advice.

 

[tig1]

Under normal useage 50K for M1 is very conservitive. We used in a Ford Ranger for 354 K with two changes. The fluid still looked good and clear. Also in my old Merc GM with 218K had two changes.

 

[gathermewool]

REALLY, ALL CAPS!? I WAS EXPECTING SOMETHING MORE SEVERE...

 

[dwcopple]

LOL^

 

[artificialist]

First change at 10,000-12,000 miles, 50,000 miles after that.

 

[Zaedock]

I did the 8.8 and 9.75 axles in my F150 at 54K and will probably do it again this summer at 100-something K.

 

[dubie2003]

My OCD nature causes me to change it every 20k with m1. Yes, this is sooner then what is needed but with the vent cap issues and the possibility of water intrusion, I am happy to eat that little cost in the grand scheme on thing.

 

[BISCUT]

Originally Posted By: gathermewool
REALLY, ALL CAPS!? I WAS EXPECTING SOMETHING MORE SEVERE...


Sorry to dissapoint........

 

[BISCUT]

The addition of the PML cover allows for increase in fluid volume and heat dispersion is much better than stock with their covers. BIG bonus is the addition of the magnetic drain. Literally 20 minutes, no RTV to deal with and your done!

I am planning on doing the front at 50k and the rear every 30k.

And...I always change the transfer case when I do the transmission (drop pan/filter) which is 30k for me.

 

[LoneRanger]

Maintenance schedule for my Subaru calls for it every 30K. 60K seems long. I changed it out on both diffs at 12,000 when it was new though, due to my BITOG oil OCD. Not due til 42K now. Used Supertech semi-syn.

 

[sw99]

Gee, i'm at 122k on the original diff fluid and transfer case fluid. Perhaps that should be my spring project...

 

[01rangerxl]

Honestly, you're probably good for at least 100K miles.

Ford's reccommended interval for the little 7.5" diff in my Rangers is 150,000 miles.

I change it sometime after 50K, but sometime before 100K. I put Royal Purple in my Ranger's diff a couple years ago and don't have any plans to change it soon. I can't even remember how many miles are on the fluid now, probably 60K or so. Still looks good and the diff isn't complaining.

 

[Kestas]

Originally Posted By: artificialist
First change at 10,000-12,000 miles, 50,000 miles after that.

I think this is the best answer. Most of the break-in is complete after 3-5K.

Have any of you ever changed it a second time on your vehicles? Generally there is none of that wholesale metallic glitter that you see in the first, break-in change.

 

[4x4chevydude]

My truck i changed at like 120k I believe front and rear looked good refilled with Lucas