Gen 2 Rear Diff

[gavin T]

checked my rear diff fluid and it needs to be replaced (130k) i wanted to pull the cover and clean it out thoroughly with brake clean and then use a lube locked gasket for the ford 8.8 and seal her back up. but the rear diff cover bolts into the crossmember right behind it...?

anyone advice on this or have a how to?
*i want to eventually put a truetrac or helical lsd in but i have to replace my drive shaft and Tcase rear seal first

 

[Todd Z]

Correct, COMPLETE removal is necessary.... I just drain, then pump in any 80w90 el cheepo, let it flush and drain, then correctly fill.

OR fill it with regular 80/w90 for a week, drive slow, no towing or racing, then drain that and fill with proper synthetic.

 

[gavin T]

thanks for the information. been searching EVERYWHERE for it.

rear diff fluid is really bad. found my next weekend project before i get the drive shaft replaced.

 

[Johnny O]

Gen 2 rear diff cover has a drain plug. Just drain it, wipe the shavings off the magnet on the plug, and refill it. I do mine every 30k, also the transfer case. Rear diff calls for 75w-140 synthetic. Front on 4x4's calls for 80w-90 although you will not get the cover off with the diff in the truck. I take mine to the Valvoline Qwicky Lube every 50k and they do it with their machine.

 

[gavin T]

Gen 2 rear diff cover has a drain plug. Just drain it, wipe the shavings off the magnet on the plug, and refill it. I do mine every 30k, also the transfer case. Rear diff calls for 75w-140 synthetic. Front on 4x4's calls for 80w-90 although you will not get the cover off with the diff in the truck. I take mine to the Valvoline Qwicky Lube every 50k and they do it with their machine.

any recommendations with gear oil? and how many quarts do you normally use when re filling? at work and cant check my manual

i checked it about a month ago. and its pretty thicc in there. might run 80-90w for a week then drain and put in the 75-140 to help flush out some of the thicc stuff

 

[Todd Z]

any recommendations with gear oil? and how many quarts do you normally use when re filling? at work and cant check my manual

i checked it about a month ago. and its pretty thicc in there. might run 80-90w for a week then drain and put in the 75-140 to help flush out some of the thicc stuff

That's what I did in mine - I believe you need 2.5 qts

 

[gavin T]

That's what I did in mine - I believe you need 2.5 qts

manual says 3.5pts
i put in two qts. and it wasnt over flowing. but holy crap that was the worst looking fluide ive seen. and the drain and fill plug were covered in metal. draining and refilling this week with the 75w-140 synthetic. anyone know a cheap spot to get be fill or drain plugs mine have damaged socket and threads rather pay 10-15 bucks and never deal worry again.

 

[gavin T]

follow up :

ran the 80-90 for 1 week. put about 200 -300 miles on it. and the truck felt good but i could hear a high pitch groan/ hum form the rear diff. (2 qts) after swapping my broken drive shaft and the diff fluid i saw 1 mpg increase. after a week i put the 74-140 gear oil (~2Qts) back in and lost some mpg but the diff is not squeeling or humming so i am happy.
btw my rear diff fluid was oem... 135k on it... boy oh boy did it smell and i had a ton of metal on the fill / drain plug. they did there job!


* had to drive the car around for 20 minutes in order to heat up the rear diff enough to use a BREAK BAR to get the drain plug out. it was seized on. put anti sieze on them both and snugged them up. going good!

now if i could only pin point this damn vibration

 

[Johnny O]

any recommendations with gear oil? and how many quarts do you normally use when re filling? at work and cant check my manual

i checked it about a month ago. and its pretty thicc in there. might run 80-90w for a week then drain and put in the 75-140 to help flush out some of the thicc stuff

Sorry it took me a while to get back. Trouble logging in to the site. I use Mobil 1 75w-140 gear lube and change every 30k. You do not need to add friction modifier.