Changing the Differential Lube

[BigCarl64]

I am getting ready to change the differential oil myself and wondering about the best way to seal the cover back on. Any aftermarket gaskets better than OEM, which RTV sealant to use?
I know what gear lube I want to use, just not sure about correcttly sealing the cover back on.

 

[Alan Reagan]

This Ultra Copper by Permatex is supposed to be good stuff. The Ultra Black (what I used last time) meets the OEM specs for Ford, GM and DC. The Ultra Copper supposedly is the top of the line. Last time it took five days for me to see a problem. I'm going on a 200 mile drive this afternoon and will know by tomorrow if I got it. This is the first time I've ever had a cover leak so I'm very surprised. It's like the sealant was bad. When I say completely dissolved, I mean there was barely a film left and followed the directions exactly. One thing I like about this Ultra Copper is you can really see it. Once the excess squeeze was wiped off it left a nice, thin orange gasket between the cover and the axle.

 

[Neal Cassady]

My dad taught me this technique about 25 years ago, have been using ever since, never had a problem and it makes servicing the diffs pretty easy.

Find a good quality Dana/Spicer gasket(s). Should be able to find them at a distributor for less the $5. Remove diff cover, drain and clean diff housing and gears. Throughly clean diff housing and cover mating surfaces. Apply a thin coating of gasket tack to the diff cover. Allow tack to become tacky. Carefully place gasket on diff cover, use cover bolts to align gasket to cover, press gasket firmly into place. Allow some time for drying. When replacing cover on diff housing coat the diff housing with a light film of high quality grease. Install cover and torque to spec in proper pattern. A little grease will be squeezed from between the cover and housing. Clean off excess grease. When you need to service the diff next time the cover should come off with no trouble and the gasket should remain attached to the cover. I usually give the diff housing and vicinity a good cleaning before I open it up.

Dave D

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2001. 5 QC, LB, 4x4, Auto, 3. 54, Everything but Leather, Bright Silver Metallic, ARE K Series, Diprocal EGT, Boost and Autometer transmission Temp(sensor in the line) in an Autometer Dash Pod, ,Westin CPS Platinum Step Bars - Black on Stainless

[This message has been edited by Dave D (edited 03-15-2001). ]

 

[Alan Reagan]

Good tip. The parts guys tried to find me a gasket and couldn't. I've got the feeling that when I do this again, I'll be scraping off Ultra like I did the OEM sealer. I would like the gasket sticking to the cover though. I may break down and go with a Mag Hitech next time. This was an out of the blue "I think I'll do it now". Heck, it was so much fun I did it twice #ad
.

 

[John Berger]

Originally posted by Alan Reagan:
I may break down and go with a Mag Hitech next time. This was an out of the blue "I think I'll do it now". Heck, it was so much fun I did it twice #ad
.

Alan, I can't say enough about the Mag-Hytec. I installed mine almost two years ago. Never have lost a drop, plus it looks good and makes monitoring your fluid easy. Well worth the money.


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1999 Dodge Ram 3500 Quad Cab 5 spd; 4:10 LSD rear; Mag-Hytec diff. cover; US Gear EGT and Boost gauges. Amsoil foam air filter and synthetics from nose to tail.
Cummins Power, don't leave home without it

 

[Alan Reagan]

I may give you a call John. Just a final report... ... The Ultra Copper didn't leak on the trip to Savannah and back. Looks good. Next time I change it though, I'll be going to the Mag cover. One other thing. I still haven't added friction modifier with this last synthetic and all seems to be working just fine. Good traction, no chattering on corners. It's a done deal.

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2001 HO 6 spd 2500, 4. 10 LSD, Towing Package, Electric Brakes, SPA EGT/Boost Gauges, Fog Lights, Real Backup Lights, Molded Running Boards

 

[Cooker]

I agree with Dave D 100% on the gasket tip. Got both front and back gaskets at a driveline shop for $7. The light film of Permatex makes them easy to get off next time, IMO.

Alan. I'd agree that a 75-90 is easier flowing when cold, if using a conventional oil. With syn the pour points are close to the same (with some MFG's) so with "warming" up there is little difference in cold flowability. Also the 75w on the bottom end for both ensures the same "cold" viscosity.

There was a post here a while back where someone contacted Dana/Spicer to ask the question of gear lube. Dana recommended syn 75w140. JMO, Ryan

 

[John Berger]

Hey Alan, I live in Kingsland, probably not much more than 3 hours from you, depending upon foot to pedal ratio #ad
Give me a yell anytime.

John

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1999 Dodge Ram 3500 Quad Cab 5 spd; 4:10 LSD rear; Mag-Hytec diff. cover; US Gear EGT and Boost gauges. Amsoil foam air filter and synthetics from nose to tail.
Cummins Power, don't leave home without it

[This message has been edited by John Berger (edited 03-19-2001). ]

 

[Alan Reagan]

Thanks for the 75-140 info Cooker. I like the thought of the higher viscosity when towing. I won't forget that one. Last thought..... I'm wondering if this Valvoline is just right without the friction modifier. I'm almost glad at this point that I had to pull the fluid out. It seems to be working well and must not be too slick for the LSD without it. It is strange that I put it in the first time I added the synthetic and that's when the LSD seemed to start working right. I'm confusing myself now.

 

[tom sweeney]

just changed mine yesterday,i used Mobil 1 75-90 syn. i couldn't find enough Valvoline
75-140... by the way,there was NO gasket. . just OEM RTV,so i used Permatex Ultra Black... no leaks... no chattering. . no friction modifier. . i also removed the fan... easy job. tom

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2001QC 2500HD LB ETH/DEE 4x4 4:10's LSD, Pacbrake,Combo Gauge on A pillar,All options except cab lights,Xcelerator air filter,Forest Green/Light driftwood. Westin tubular black powder-coated side bars.
26'Holiday Rambler 5th wheel. Extra Class Amateur Radio Operator ke3Rx

 

[ARARAR]

What is the proper tork value and sequence for the differential cover?

 

[John Berger]

Originally posted by arar:
What is the proper tork value and sequence for the differential cover?

When I put my Mag-Hytec on I used a crisscross pattern starting on the driver's side. Torqued to 15 ft. lbs then 25-30 ft. lbs. I believe the specs are the same for the factory cover. If I'm wrong, somebody will correct me.

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1999 Dodge Ram 3500 Quad Cab 5 spd; 4:10 LSD rear; Mag-Hytec diff. cover; US Gear EGT and Boost gauges. Amsoil foam air filter and synthetics from nose to tail.
Cummins Power, don't leave home without it

 

[Alan Reagan]

I did the same thing John did. One other thing I did since I used silicon sealant. The directions say one hour to set and 24 to cure. After I put the cover on, I found something else to do for several hours (about four) before I added the lube. Be sure to read the instructions on the sealant if that's what you are using. Some say put the sealant on and let it set for five minutes before putting the cover on. Others say put the cover on immediately.

 

[WMann]

The first three trucks I did, I took the rear end cover off. What a messy pain in the butt. Now I use a pump to pump out the old stuff and pump in the new stuff, Mobil that is. It only takes about thirty minutes to do the entire job and you don't have to wait for the sealant to set up so you can refill the rear end. If you didn't have a leak before, you probably won't have one when your done doing it this way. Quick and easy.

Wayne