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How to change rear diff. fluid (axle)

Discussion in 'Chevy Trucks' started by dhv, Jan 25, 2003.

  1. dhv

    dhv Junior Member
    from 49428
    Messages: 1

    My problem is that i do not know how to change the rear diff. fluid, what kind of oil i would use, how to drain it, fill it , and if there was anything else i would need to know. Thanks!!!!! My vehicle is a 1998 Chevy 1500 5.7 350; Automatic
     
  2. Barkleymut

    Barkleymut PlowSite Veteran
    Messages: 29

    I have never performed this service on a Chevy. But on my 98 Dodge 1500, I did it once. I am mechanically inept but I did it anyways. It was very simple.

    There are 2 ways to do it. I would recommend the first one.
    1) Get a siphon and drain out all of the fluid unless there is a drain plug in which case just drain it. Then fill up the differential with the recommended weight oil. Also check the capacity and add accordingly.

    2) The way I did it. Pull off 8 or 10 bolts that hold the pan on. Then scrape off the gasket. Add the new gasket and bolt the pan back on. Then add the oil.

    The only real benefits to doing it the second way is if you have a leaking gasket or you want to inspect the differential. Like I said it is really easy either way.
     
  3. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    dhv, Welcome to Plowsite!:drinkup:

    To expand on Barkleymut's advice, Id drop the rear cover, this way you''l be sure to get all the old oil out and can inspect for excessive metal particles. I found a bearing going bad this way before it self destructed.

    I'm not sure of Chevy's oil requirements, but if you have a posi rear, you'll need oil with the clutch additives. If you've still got your owners manual, the oil should be listed there.

    To fill, put the rear cover back on, remove the fill plug (either in the cover or on the side of the housing) and add oil until it runs out the hole.
     
  4. wyldman

    wyldman Member
    Messages: 3,265

    Don't use a gasket,use silicone.You'll find the factory uses it,and may have a hard time getting a gasket.

    Make sure the diff and cover are clean,use brake cleaner or laquer thinner.Run a 1/8" bead around the diff gasket surface around the inside of the bolt holes,and replace cover.Start all bolts finger tight before pressing cover into silicone,or you'll get the holes full of silicone,which can crack the housing when you tighten the bolts.
     
  5. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    Remove the 10 bolts o nthe differential cover,you may need to slightly pry a scraper between the housing and cover to break it loose,drain the oil,clean the cover,and housing with a scraper,and parts cleaner.Now you can either use RTV silicone,or a new gasket.If you use RTV,you must make sure every bit if oil residue is gone,and wipe the oil out of the bottom of the differentila,so it wont drip while your instaling the cover.I cant stress how important it is to have the cover,and diff housing so clean,you can eat off it.If you do it right the RTV silicone is the best.,IMO. Napa carries the popuar cover gaskets here as well,you can go that way too_Once the covers on,refill thru the fill hole above/to the side of the pinion gear.it usually takes a 3/8 ratchet to loosen them.make sure you pick out the grime out of the corners of the plug before you insert the rathet or extension,and try to get it off.If you dont and the plug is tight,you may strip it out,then you will have a real hard time getting it out.
     
  6. Dan S.

    Dan S. Member
    Messages: 31

    If you decide to pull the cover to drain the oil it is a good idea to remove the fill plug first. You will be stuck if you discover the fill plug wont come out after all the oil is in the drain pan.
    Have Fun :)
     
  7. Pelican

    Pelican 2000 Club Member
    Messages: 2,075

    Hey Dan, sounds like you've been there??;)
     
  8. Mike 97 SS

    Mike 97 SS Banned
    from U.S.A.
    Messages: 1,106

    All good suggestions and I have nothing further to add except to look in your owners manual, if you have it, and see what they reccomend to use for fluid. It should say for sure in there. Mike
     
  9. PDQ Pete

    PDQ Pete Senior Member
    Messages: 139

    Its a good idea to take the truck for a ride first and warm up gear oil. I have a 95 chevy changed the oil 3 times in about 70000 miles I use a gasket from the auto parts place not hard at all.Good luck :drinkup:
     
  10. Cutting Edge Kid

    Cutting Edge Kid Senior Member
    Messages: 179

    Hey Guys,

    How often should you change the fluid?

    The Cutting Edge Kid!:confused:
     
  11. John DiMartino

    John DiMartino PlowSite.com Veteran
    Messages: 2,154

    I would use the recommended change interval for your truck,found in your owners manual,as the minimum.If you plow,or tow, especially heavy,drive at high speeds,or extreme tempetatures id change it every 2 yrs or 30K miles.Some new trucks must have synthetic fluid to maintain warranty,many of them now come with factory fill of synthetic,if they have the factory tow/plow pkgs.
     
  12. dsrour

    dsrour Junior Member
    Messages: 24

    I heard that if using synthetic lubricant you will need a gasket since it will eat through LTV.