Opinions on diff fluid change with mityvac?

Messages
141
Location
ca
Hey guys, I'm wanting to change my diff gear oil in my 04 2500 5.9l cummins 4x4. Should I completely pull the covers or will using a mityvac suck and swap be ok? Odometer is about 75k. First service.
 
Messages
6,600
Location
California
If you can get the Mityvac to pick up from the bottom of the diff, I think it should work but it could struggle with the thicker gear oil. I would try it with the diff oil warm. Pulling the diff cover isn't a bad idea if not messy. I would go that way to avoid any drama. If you were planning on swapping diff covers to a Mag-Hytec or similar with a drain plug it's also a good time.
 

229

Messages
753
Location
Mid Atlantic
Slow but better than not refreshing. Pull the covers so you can wipe out the slime. Use Mopar gear RTV or compatible black gear oil RTV silicone.
 
Messages
141
Location
ca
Pulled the cover to the rear. Gear oil was dark. But no shavings and everything was really clean. Put in 3 quarts of Lucas full synthetic 75w-90 and tightened everything back up. I think the front diff will wait for now since the rear was so clean. Too dang hot for me to be working in the sun.
 
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Messages
1,038
Location
midwest
I don’t bother pulling the cover on my truck. I just use an oil extractor every 40k miles. The process is painfully slow.
 
Messages
34,347
Location
NY
Originally Posted By: monster1
I'll pull the covers. Thanks.
If you don't have a drain plug, that's what I'd do. thumbsup
 
Messages
141
Location
ca
I towed my 4k lb boat yesterday on a 50 mile round trip. I know this is nothing for a 3/4 ton truck but the lazer thermometer showed the differential running at 150 degrees in 100 degree heat. Looks like that Lucas synthetic gear oil does it's job. I was a bit concerned I made a wring choice if lubricants because it's not a very popular product as far as the internet is concerned.
 
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