2nd Gen Non-Engine/Transmission Exact procedure for changing diff oil.

[hammersley]

I have 140,000 on my 01 and want to change my own diff oil. I watched Timberline do it once and don't remember what they did to "clean" out the old oil. Do you "wash" it out with anything? The dealer wants $230 to do both front and rear as well as transfer case! OK - What sealant do you use on the covers once you remove them? Also - is it easier to spend the $$$ for the Mag Hytec covers as you wouldn't take the cover's off again? IF I wanted to change to a synthetic - does the procedure change???

 

[TomGolden]

I didn't do anything "special" when I changed from conventional to synthetic lube in either differential, but I'm also not an expert mechanic, so I may not be aware of every little detail and best known method. Here is what did:



* Have drain bucket or whatever ready to catch old lube.

* Have putty knife, flat tip screw driver or other tool ready to pry the diff covers off.

* Have socket/open end wrench ready (I forget the correct size).

* Have new lube ready to go

* Have proper gasket material ready to go. I use Permatex High Temp Black RTV (number 598B I think). NOTE: If you are going to use a Mag-HyTec cover, they use a rubber O-ring and do not need or use any sealant.

* Have [new] diff cover ready to go if you are going with a different cover.

* Place catch bucket/pan under diff.

* Remove bottom 2 - 3 bolts, loosen all other diff cover bolts.

* Use putty knife to slowly pry diff cover off, lube will drain out so be ready/careful.

* Let lube drain, then remove diff cover completely.

* Use putty knife, rag, whatever to make certain [new] diff cover is 100% clean and free from any old sealant.

* Some people suggest alternately jacking up each rear wheel to get all possible fluid to drain out of the axle tubes. I didn't do this... maybe should have...

* Use a clean rag to wipe out as much lube that pools in the bottom of the diff housing as you can, etc.

* On diff cover, make sure any drain or temp probe plugs are securely sealed so they won't leak.

* If using a diff cover that uses sealant, run a 1/8" bead of sealant around diff cover, and fully around all bolt holes.

* Place diff cover in position, bolt it in place.

* If you used a diff cover that uses sealant, it is best to wait several hours, 24 if possible, before filling diff with new lube, to allow maximum suring time for the RTV/sealant.

* If using a diff cover that has a temp probe, and you are going to install a temp probe, do so now.

* At appropriate time, fill diff with new lube.

* Again, some have suggested jacking up each rear wheel to get new lube into axle tubes. I have not done this either.

* Of course, check for any leaks. Do this again after say a full day of driving the truck.



I have MagView covers on both ends. They are similar to the Mag HyTec covers, but have lexan windows in them so you can actually see your fluid level. Also, they do not have a dipstick as the Mag HyTec covers do. They also use sealant instead of a rubber O-ring to make the seal. I've had mine on for about 2 years, no problems with them so far.



I'm sure other, more knowledgable folks will add any other tips I missed, or correct any mistakes I may have listed here.



Tom

 

[hammersley]

TomGolden - thanks

Great stuff - Tom - why did you choose the covers you did over the Mag Hytec? Does your's have a drain plug?

 

[grtescpa]

Originally posted by hammersley

I have 140,000 on my 01 and want to change my own diff oil. I watched Timberline do it once and don't remember what they did to "clean" out the old oil. Do you "wash" it out with anything? The dealer wants $230 to do both front and rear as well as transfer case! OK - What sealant do you use on the covers once you remove them? Also - is it easier to spend the $$$ for the Mag Hytec covers as you wouldn't take the cover's off again? IF I wanted to change to a synthetic - does the procedure change???

Here is how I did mine: 1. Drive it till the until is warmed up. 2. Remove the cover and let drain for an hour. 3. Take a small dia long shaft screw driver with a rag tied around it and wipe out the sides and bottom of the gear case to remove any sludge. Clean the cover and case gasket area with solvent. Use the dealers silicon sealant and apply an even amount on the cover. Re-bolt and torque to spec. Fill to the proper level with the recomended oil. Your done. Its that simple.

 

[FDziurda]

Changing Front Diff Lube

Hi Hammersley,



I recently changed the lube in my front differential.



I removed all the bolts except a few on the top center of the cover. Use a putty knike or similar to pop the cover loose from the housing and let the oil drain for an hour or so.



After most of the oil has drained out, use a clean lint free rag to wipe any residual oil from the insides of the housing and the gears. I used a can of spray brake cleaner to wash any residual oil from the housing and gears. It dries very quickly and leaves little to no residue.



Clean the cover until it looks like a new one I even repainted mine, since I had a can of flat black hi-temp engine enamel.



Use a gasket scraper to remove ALL of the old silicone sealant. I used lacquer thinner or MEK to make sure no oil remained on the gasket mating surfaces. They must be absolutely clean before putting the silicone on them.



Coat both surfaces with an even coat of Hi-temp silicone (Gray or Red) and reassemble. Let sit for 12-24 hours, if you can, before re-filling, so the silicone has a chance to cure. Never had any leaks or problems. I re-filled my front housing with LE 607.



Good Luck,



Frank Dz

 

[RRFinch]

I just changed mine today as a matter of fact. I even read the service manual for procedure. The other posts give you good advice.

I would add: Do not use anything other than a clean lint free rag to clean the inside of the cover or inside the diff... book advice.

Use a liquid sealer, like Permetex, around the rim of the cover. I like to use the orange high temp stuff, but I think the blue would work ok.

 

[Extreme1]

Excellent advise above! I agree with warming up the rearend before draining, it also gets all the solids suspended so they drain out too.



I did jack up the sides to drain the axle, it doesn't get you any more out, the rear hubs have their own "sump" in the hub. The only way to change it is to remove the hub and drill and tap a hole in it like I did (try a search on BOMBed rear hubs) but I don't recommend it unless you have the hubs off, are bored or are a lube oil freak.



Do let it drain for a long time, do use a lint free rag to swab out below the ring gear, do not rinse the area unless you really feel confident that you are using a lube that leaves no residue and that you will get every drop of it out (hard to do if you get the diff wet). ALLOW NO RESIDUE YOU SCRAPE OFF THE GASKET SURFACE TO LAND (or stay) IN THE DIFF. It will have metal (rust) and dirt in it and it will take out bearings. I cover the diff with paper towels and pack more around the top so none will land inside. Of course, it is unnecessary now that I have a Mag-Hytec cover.



If going with the Mag-Hytec, follow the instructions regarding filling the imperfections in the housing surface with epoxy. I bought mine used and the previous owner included everything that he recieved with the cover except that sheet. It leaked.

 

[swampfox]

Another way.



Unscrew rear diff. plug; use hand operated suction pump to remove fluid. Refill with appropiate amount and type of fluid. Replace diff. plug. Ditto for front diff.



On my 2001. 5 HO (at 47K miles) rear diff. I removed 10. 0 pints (spec says it holds 10. 1 pints) with the suction pump. I don't think the remaining 1. 6 oz of fluid will be a problem. I replaced the fluid with Royal Purple 75W-140... no friction modifer needed. The Royal purple cost me $7. 95 /Qt. For the Transfer case I used the Mopar stuff... . cost me $27 for a gallon. Total cost front/rear diff and transfer case was approx. $99... . Dealer wanted $300. It took me about 2 1/2 hours since this was the first time I did it. Now I think I could do it in about 1 hour. So far I have 56K miles and no leaks or problems.