Differential fluid change for 7.5 axle

Topic: Differential fluid change for 7.5 axle (Read 1470 times) previous topic - next topic

Differential fluid change for 7.5 axle

October 26, 2016, 12:37:22 PM

My passenger side brake backing plate has been repaired so it's time to put it back on the axle tube, reinstall the axle and replace the differential fluid. I'll certainly clean the inside of the cover but how far should I go in cleaning the inside of the housing? Do you guys recommend using RTV or an actual gasket to seal the cover to the housing? Also, what weight of fluid should be used? I have a 7.5" 3.08 non-locking rear in an '84 Thunderbird.

Thanks in advance!

Differential fluid change for 7.5 axle

Reply #1 – October 26, 2016, 08:10:42 PM

I usually run 75W90 gear oil. Use "The Right Stuff" RTV for the differential cover, no gasket.

Differential fluid change for 7.5 axle

Reply #2 – October 30, 2016, 10:48:40 PM

Paper gaskets are for differentials. Unfortunately no one makes anything like THIS for a 7.5....

Differential fluid change for 7.5 axle

Reply #3 – October 31, 2016, 06:06:15 AM

Quote from: V8Demon;457562

Paper gaskets are for differentials. Unfortunately no one makes anything like THIS for a 7.5....

It's because they're too busy designing diapers for when they scatter the gears.

Differential fluid change for 7.5 axle

Reply #4 – October 31, 2016, 07:04:13 AM

You're thinking more the GM 7.5

Remove spider gears; problem solved.

Differential fluid change for 7.5 axle

Reply #5 – October 31, 2016, 09:45:32 AM

I usually just use paper towels to get as much of the excess oil out of the housing. Then I use carb cleaner to more or less wash everything down and then put a paper towel in the bottom of the housing to soak all of that up as well. I then use compressed air to really dry the housing, gears, and posi out as much as possible before putting the diff cover back on. Install the diff cover using RTV and I usually let that sit for at least an hour before putting the gear oil in. I run Mobil1 synthetic gear oil in both of my Fox's and for those with a limited slip rear don't forget the clutch additive.