Changing Rear Diff Fluid..have A Few ?s

[davo32683]

Alright guys, just was getting ready to swap the oil in my rear diff. Only come to find out, it doesn't appear that I have an actual drain plug!? It seems I have a fill plug on the upper portion passenger side, but there is nothing on the lower portion. Does this mean I have to remove the cover to change my fluid?! I can provide pics if that helps.

[davo32683]

Well obviously I'll have to remove the cover, but this seems stupid to me....haven't seen this before.

[yfz450dk]

yeah... you have to take the cover off. They dropped the drain plug in like '03 or something. Its not too hard.. make sure you use a new gasket and some RTV.

[az'03Silverado]

The tech at the dealer told me to just put the gasket on dry. I did and torqued the bolts to spec with zero leaks.

[Ben]

Some of the newer diff pumpkins have a drain plug in the

casting or cover.

 

Remove the cover and make sure to have a catch pan underneath.

It's going to messy.

 

Then scrape off the old gasket, making sure to not get any into

the differential.

 

For this without, here is a trick to never have to use a gasket again.

 

Clean the flanges on the cover to remove all grease. Glue a new

gasket onto the cover and DO NOT glue the pumpkin flange, nor

the gasket on that side, but put some diff lube on that union.

 

Then bolt it up finger tight and only finger tight to get the glue

evenly distributed, but not squished out. Allow the glue or gasket

sealer to set, then torque the diff bolts to spec.

 

The next time you change the diff lube, just loosen all of the diff

flange bolts, but leave them in (engaged by about 1 full thread).

 

Wack the diff cover in the middle with a rubber mallet and it

will 'pop' off, but be held by the bolts.

 

The lube will drip out of the 'gap' into the catch pan underneath.

 

Take off the bolts, inspect/clean/etc, rebolt to spec and fill.

 

Done...

[Ben]

DO NOT use silicone RTV if you use synthetic, as it will react and potentially

cause leaks.

[davo32683]

how about using this stuff? http://www.permatex.com/brand_right_stuff.htm

 

anybody know the gasket PN?

[davo32683]

Also, is there a good way to clean out the diff well? Brake cleaner or something maybe?

[RCman]

how about using this stuff? http://www.permatex.com/brand_right_stuff.htm

 

I've always used either the one of these:

http://www.permatex.com/products/automotiv...asket_Maker.htm

http://www.permatex.com/products/automotiv...asket_Maker.htm

 

I've never had any trouble with synthetics (Amsoil or Mobil 1) and either of those above.

 

Also, is there a good way to clean out the diff well? Brake cleaner or something maybe?

 

Yup, I've always used non-chlorinated brake cleaner. I use the full can to do the set (half front / half back).

I also always pull the cover even if there is a drain plug. It's a good way to inspect for wear or other problems. A good trick is to remove all the bolts but the upper most one. Remove that upper most one about half way to allow the cover to move and this will control the flow of the draining fluid until the differential is empty.

[cmoore74]

Maybe this was a coincidence, but shortly after I changed my rear diff fluid I got an infection on one of my fingers between the cuticle and the finger nail (called a paronychia). I've heard that gear oil is nasty stuff. I did get my hands covered in gear oil.

 

Assuming it was the gear oil that was the cause, some rubber gloves might be a good idea or at least mechanics gloves and try not to get your hands soaked in old gear oil.

[Tahoetime]

how about using this stuff? http://www.permatex.com/brand_right_stuff.htm

 

I've always used either the one of these:

http://www.permatex.com/products/automotiv...asket_Maker.htm

http://www.permatex.com/products/automotiv...asket_Maker.htm

 

I've never had any trouble with synthetics (Amsoil or Mobil 1) and either of those above.

 

Also, is there a good way to clean out the diff well? Brake cleaner or something maybe?

 

Yup, I've always used non-chlorinated brake cleaner. I use the full can to do the set (half front / half back).

I also always pull the cover even if there is a drain plug. It's a good way to inspect for wear or other problems. A good trick is to remove all the bolts but the upper most one. Remove that upper most one about half way to allow the cover to move and this will control the flow of the draining fluid until the differential is empty.

 

 

 

 

 

 

 

I'm getting ready to do this same service to my truck, so I'm just wondering if you spray the gears off with the brake cleaner? How about the clutch pack? Will it harm the clutch pack on a limited slip??

[RCman]

I'm getting ready to do this same service to my truck, so I'm just wondering if you spray the gears off with the brake cleaner? How about the clutch pack? Will it harm the clutch pack on a limited slip??

 

 

I've always shoot the entire thing. Ring/Pinion, carrier, clutches (if equipped), etc. If it's your first time (as well as your truck's) I think you'll be surprised how much grime comes off.

I've always used the CRC BRAKLEEN Non-Chlorinated Brake Cleaner (or any similar product will do). Add the correct fluid (and additives if needed) and you should be fine.

 

 

Picture:

[Taaaaaaahoe?]

I'm getting ready to do this same service to my truck, so I'm just wondering if you spray the gears off with the brake cleaner? How about the clutch pack? Will it harm the clutch pack on a limited slip??

 

 

I've always shoot the entire thing. Ring/Pinion, carrier, clutches (if equipped), etc. If it's your first time (as well as your truck's) I think you'll be surprised how much grime comes off.

I've always used the CRC BRAKLEEN Non-Chlorinated Brake Cleaner (or any similar product will do). Add the correct fluid (and additives if needed) and you should be fine.

 

 

Picture:

 

 

I always have used this as well, but i have also heard that you should not do this... NO idea why.

I just used a gasket, and no RTV - no leaks for me!

[davo32683]

Does anyone know the gasket part number?

[cerbomark]

did my 04 SS silverado by just loosening bolts enough to carefully pull open enough for fluid to drain without removing bolts, then retighten and refill. Never leaked after that. Be careful not to overtighten!