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Opinions on diff fluid change with mityvac?

Posted By: monster1

Opinions on diff fluid change with mityvac? - 06/04/18 04:39 PM

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.
Posted By: nthach

Re: Opinions on diff fluid change with mityvac? - 06/04/18 05:11 PM

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.
Posted By: 229

Re: Opinions on diff fluid change with mityvac? - 06/04/18 05:43 PM

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.
Posted By: monster1

Re: Opinions on diff fluid change with mityvac? - 06/04/18 06:09 PM

I'll pull the covers. Thanks.
Posted By: monster1

Re: Opinions on diff fluid change with mityvac? - 06/04/18 09:06 PM

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.
Posted By: JEL01

Re: Opinions on diff fluid change with mityvac? - 06/04/18 09:10 PM

Good on you for taking care of it,
You are now ahead of 99% of other drivers, BITOGers excluded smile
Posted By: Billy_D

Re: Opinions on diff fluid change with mityvac? - 06/04/18 09:27 PM

I donít bother pulling the cover on my truck. I just use an oil extractor every 40k miles. The process is painfully slow.
Posted By: demarpaint

Re: Opinions on diff fluid change with mityvac? - 06/04/18 09:45 PM

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
Posted By: monster1

Re: Opinions on diff fluid change with mityvac? - 06/06/18 04:13 PM

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.
Posted By: zeng

Re: Opinions on diff fluid change with mityvac? - 06/07/18 01:05 AM

150F diff temperature towing is fantastic for Lucas 75W90 with a high [email protected]*C of 142 cSt.
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