Drain/fill diff

[JBDISCOVERY]

Gentle Persons,
What is the proper procedure for draining and replacing the Diff fluids? Bottom up/top down? Also are the Syn fluids best?
Thanks.
Regards,
JimB

[Randy blase]

I just got done doing mine make sure it's pretty level pull bottom plug after draining put plug back in remove top plug and fill till it starts running out replace plug and u are done

[Oldkarphart]

Bottom up/Top down???
Not sure what you're asking, but just remove the drain plug and empty out the diff. then refill at the refill plug.
Be careful if you switch to synthetic, you might start having a seal leak problem.

[Hooligan]

JimB- The August issue of Motorhome magazine has a tech article on Rear Axle Service. Only thing I would add to Randy's post is to clean the magnetic drain plug (bottom) before installing, and to clean the area around the plugs so you can see any seepage.
Meritor has recommended gear oils and allows longer change intervals for using synthetic. I've not had seals leak after going to synthetic on the MH but I did on my motorcycle, so that's a consideration.
Meritor Lubicant link:
https://s3.amazonaws.com/helm-arm-lod/tp9539.pdf

[wagonmaster2]

I've never had any problem but I've read you should remove the top fill plug before draining just in case the top fill plug won't come out. If it proved to be stuburn to remove you'd be in a pickle with the fluid drained and unable to refill. Just a thought.

Wagonmaster2

[wa8yxm]

Good point Wagonmaster (Make sure you can refill before draining)

Today's RV job: Refilling. due to an axle seal leak.

I set a few tools and a half bottle of gear oil behind the tire

Crawled under the rig (I can do that with jacks retracted if I so desire)

Grabbed the "Tire changer" this is a 1/2 inch drive battery operated impact wrench.

Stuck the half inch square end in the half inch square hole in the plug and tapped the triggure, Hammer, Hammer WIRR the plug came out no trouble at all.

Added what was in the bottle

Hand started the plug back in, pushed the direction selector on the wrench and tapped it back in.

I get the seal replaced on the 25th.