Differential draining

[DZLFREK]

New guy question and first post so be patient. My dealer gave me absolutely no help in "diesel 101" and all I've learned is from all of you. Thank you!

I've read that some change their oil by pumping out the oil via the dipstick. Could this method work good on the diff as well? I'm thinking this would keep the rear/ front seal in place and stop any chance of leaking. If this is a bad idea, then a detailed briefing on how to change the fluid (front and back) would be helpful since it's time to change the oil and I've never done this before. Thank you in advance.



David

 

[ttbird]

I suppose you could drain it that way but the oil is pretty thick, almost molasses like, be pretty hard to get it out. Get a new gasket, you may not have to use it, if the old one doesn't tear when taking it apart. Or you can use silicone RT and no gasket. I still use gaskets but that's me. When you get the cover off it's easy to check that rear for metal shaving and anything else that might be looking BAD. You would miss all that if you just pumped the lube out.

Oh, welcome to TDR, everyone was new at one time

Tom

 

[AWay]

Can't give you advice on the front, I only have 2wd, but for the rear it's easy. I would suck it out. The gasket is re-useable and draining is easy. Just back off the top 3 bolts a little, then remove the remaining bolts. The cover will swing loose and fluid will drain. Then you can remove the cover and clean all surfaces. Replace the gasket and cover and your ready to fill.



You 4WD, isn't the front case the same?

 

[JApol]

If your truck is a 3rd generation, 2003 and up, the diff covers and transmission pan have a reusable seal. Just loosen all the bolts and take the bottom ones out. Get the bottom of the cover to come off a little bit and the oil will drain out. Once its done dripping take the cover off and inspect inside for wear metals and anthing that just desn't look right. Clean out the rest of the oil, put the cover back on and refill and the job is done.

 

[GECCO]

^^^ What he said. The gaskets are resusable. I would recommend driving the truck for a while first, especially if it's cold where you are, to get the gear oil good and warm. This will make it drain faster and more thoroughly. If you have the time, let it drip out overnight, then refill the next morning.



Be sure to use synthetic lube in your diffs, and NO posi additive in the third generation limited slip rearends.

 

[RJOL]

If you really want to make this easy find someone that is a good welder. The first time you remove the covers, have him weld in a bung at the bottom that you can put a magnetic plug in. For all future oil changes, just take the plug out, look for abnormal metal on the magnet, close it up and refill. Works for me...

 

[DPKetchum]

There have been issues with posi shutter where additive has been used in 3gs. Carson Dodge says it is NOW advised to use it. BUT AAM says no additive. I have experianced posi shutter in mine. Been trying to find the FACTS about this issue but all I get is finger pointing in other directions. I have found posts about posi shudder in these AAM axels and additive fixed them or hindered posi operation. Not sure which. Carson Dodge says D. C. says to use additive now but I have not seen such in print. AAM says thats new NEWS to us. Any one have a clue to any of this?

 

[Midnight]

Remove the cover like everybody else has said. There is a flat magnet on the bottom you can take out and clean. You kind of have to look for it, because it is flush with the bottom.

 

[DZLFREK]

TTbird- Thanks for the welcome. Loads of information. Trying to put it in a laymans format is the challenge.



AWay- Don't know about the front. Totally new to all of this. I assume changing the lube is the same. Anyone know any different?



JApol- Thank you. How do you like the GDP 2 micron filter? Was it hard to install?



GECCO- Good idea. Cold up here right now.



RJol- Interesting.



DPKetchum- Wow! I'll go with the no-additive.



Midnight- Didn't know about the magnet. Thanks!

 

[GECCO]

JApol- Thank you. How do you like the GDP 2 micron filter? Was it hard to install?

I'm not JApol, but I just installed the GDP 2 micron "big line" kit and it was a snap. It's not terribly complicated and their directions are excellent.

 

[JApol]

It took me almost 3 hours to install mine. :--) But that wasn't my fault. i had everything installed and ready to bleed in just over 1. 5 hours. When I hooked up the batteries Murphy entered stage rear and locked the doors with them closed and the windows up.

I have no idea on what caused the doors to lock but it happened as soon as I connected the first battery.

It cost me $40 to have some one come on base and unlock my truck.

 

[robertyoke]

There have been issues with posi shutter where additive has been used in 3gs. Carson Dodge says it is NOW advised to use it. BUT AAM says no additive. I have experianced posi shutter in mine. Been trying to find the FACTS about this issue but all I get is finger pointing in other directions. I have found posts about posi shudder in these AAM axels and additive fixed them or hindered posi operation. Not sure which. Carson Dodge says D. C. says to use additive now but I have not seen such in print. AAM says thats new NEWS to us. Any one have a clue to any of this?

friction modifier is for clutch style lsd. the modifier keeps the clutches from chattering. the aam does not use that type of lsd. I doubt it would hurt anything, just make your wallet lighter.

-robert

 

[HallC]

How much fluid and what weight should be used on each differental?

 

[GECCO]

How much fluid and what weight should be used on each differental?

Anything synthetic in the 90weight neighborhood (ie 75W-90) will be OK. Personally I like the Mobil 1 product line but everyone has their opinions on what is the best. You'll need 3 quarts for the front and 4 quarts for the rear, you may have just a little left over but not much.