How often to change rear end oil.

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Driving regularly, every 30K or so. If it sits all winter and you just drive it seasonally opinions vary. I change mine every spring. If you have a suregrip, don't forget the additive.
 
As long as it ain't leakin, leave dat chit alone.
 
Put a nice strong magnet in there somewhere below the normal oillevel and clean it out every once in a while.
You won't believe how much metallic 'goo' accumulates on it after a while.
Without a magnet all this fine iron-goo is constantly churned and run through the gears and bearings.
 
Mines been in there for about 6k and looks bad, plus noticed the pinion seal has a very slight leak. I got some Torco RGO 85/140 and ford friction modifier ready to go in. I'm just going to use a suction gun on my 8.75. I think more HP and amount of burn outs and full power takeoffs require more frequent oil changes.
 
I change them when I first buy the car and maybe again 40-50k later if I still own it
 
If your rebuilding an 8.75 or doing a pumpkin swap drill a hole in the bottom, tap it 1/8 NPT and install a brass drain plug. Also lay a magnet in the bottom to catch the metal debris.
 
mderoy340 said:
If your rebuilding an 8.75 or doing a pumpkin swap drill a hole in the bottom, tap it 1/8 NPT and install a brass drain plug. Also lay a magnet in the bottom to catch the metal debris.
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Yup, that's what I did. Makes life easier, lol.
 
BlueDream said:
The oil in my 8 1/4 is from 1973. Grandpa never changed it and neither have I. I probably need to though lol
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Probably wouldn't hurt. Oil doesn't break down. If nothing gets hot enough to cook it, it will last a very long time. I am not recommending NOT changing it, but I think sometimes people make much ado about nothing over it really.
 
Thanks for the replies. It hasn't been changed since the mid 90's. It's a Dana 60. So I guess I should change it.

Fred B
 
This thread was of interest to me, because I wanted to know the same thing.

Yikes. I have almost 150,000 miles in my Ford Ranger's 8.8 since I put the 4.56 gears and Detroit Locker in. Maybe I should change it? LOL

In my Duster, I have the rear end (8 1/4) sitting on jack stands and I was going to take the diff cover off to take a look and change the oil while I was at it (kinda need to once I take the cover off anyway). The car is actually sitting on a B body 8 3/4 but I don't think I'm ready to pull the trigger on that one. I'm just mocking it up for now.
 
If anyone decides to change you're rear end oil here's a tip that believe it or not is a fact use synthetic gear lube ( I used Royal Purple Brand ) as it does make a huge differance in the gear life, I had an 8-3/4" rear in my race car before I put the Dana 60 in and used a log book and I got 50 runs out of a set of gears as my car left real hard with the Royal Purple oil I got 75 runs out of a set ??? If someone told me that I'd have call it bull **** but I can tell you it is true . I sold the car years ago and the Dana 60 has never broken a gear set so if you have some serous HP use a Dana 60 and Royal Purple is the only way to go .
 
Valiant Steve said:
If anyone decides to change you're rear end oil here's a tip that believe it or not is a fact use synthetic gear lube ( I used Royal Purple Brand ) as it does make a huge differance in the gear life, I had an 8-3/4" rear in my race car before I put the Dana 60 in and used a log book and I got 50 runs out of a set of gears as my car left real hard with the Royal Purple oil I got 75 runs out of a set ??? If someone told me that I'd have call it bull **** but I can tell you it is true . I sold the car years ago and the Dana 60 has never broken a gear set so if you have some serous HP use a Dana 60 and Royal Purple is the only way to go .
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That's weird. Mark Williams and some others say to NOT use synthetics. I don't dought your experience.
 
Ford it's like $7 at the dealer for 4 oz. Dr diff recommends it along with conventional 85/140
 
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