BossHogg

Im thinking of changing my rear diff fluid myself w/ royal purple, but cant find in the manual how to do it. How hard is it and how do I go about doing it? Any help is greatly appreciated!!!!

Jezzhuntin

get tote plastic type bucket (something wider and not as tall as a bucket), loosen the bolts, let drain. some will tell you don't have to take off the cover, but I like to inspect, clean with some brake cleaner and wipe out good. the gasket is reuseable, so just clean up and re align. i am pretty sure there are torque #s for the bolts, but I just tighten snug. re fill and go. I used one of those cheap pumps, it worked, but was a little slow.

Jezzhuntin

oh yeah, if i can do it anybody can! it is easy just takes a little time.

Hot Rod 4

Its real simple don't worry. Put a drain pan under the rear diff, then loosen and remove all bolts holding the cover on the diff. I usually leave in one at the top so the cover doesn't fall. The cover might be stuck on there pretty good so take a screwdriver and a hammer wedge it in there to pry it off. Once all the fluid is removed clean the outer sealing edge of the pan and apply a 1/8in. beat of silcone along the egde. reinstall the cover and install all the bolts. Locate the fill plug(could be on the back of the cover or around the pinion can't remember.) Then just fill the diff till the oil just begins to run out of the hole

And your done. Hopefully you have plenty of gear oil as these things hold alot. Any other questions feel free to ask.

OOPS

You should also change the front at the same time since the gears turn all the time. Same as rear. I always take them out for a drive to get the oil warmed up, it flows out better.

new2ctd

Torque thread
http://www.dieseltruckresource.com/d...d.php?t=157580

Jezzhuntin

I agree. it will say in your manual how many quarts, I think 7. I am no mechanic, but I disagree with Hot Rod, I wouldn't pput silicone on it, IMO. it is a reuseable gasket. you would a new one next time. I changed front and rear at 34k and i have no leaks. (now at 60k)

05 CTD2500

to summarize for you:

30 ft lbs on all bolts (front and rear diff covers) is what the manual says, the bolts are cheap and may break if you go that high. I just did mine and torqued them all to 21 ft lbs and all is well so far.

Also, didn't see anyone mention it. 75W-140 is what is supposed to go into the AAM's now, the manual will say 75W-90.

Luvnacumns

It just as simple as Jeez explained!!! Nothing to worry about!!! Once I loosened my bolts it fell off!!

Roperteacher

The MAnual doesn't call for 75/140 officially. On my new 07 it still says 75/90. I went with AMSOIL 75/110 and added a PML cover. With the PML cover there is a drain bolt. Simple as cake!! The gasket is reuseable, no silicone needed..

Coolhand37

So is the accepted method of refilling them; fill until some fluid comes back out of the fill hole?

tcr

Yep, that's what everyone does. I'll park on a hill, so I can get it as full as possible.

LongRanger

How much fluid are you actually putting back into your AAM 11.5s to fill to the max? Thanks.

tcr

The rear on mine takes 4.5 qts, the front about 3.25 qts. Factory covers.

PoorMansCat

Boss, being that you live in a hot weather climate, I'd go ahead and put the 75/140 in it. My gear oil looked terrible when I changed it. Most I have pulled to date is about 5,000 lbs. I'm feeling much better now that its got the Hy-Tec cover on it. Doubled my oil capacity and runs cooler.