Few chevy 2500 hd fluid changes

[ausdoug]

I'm new to the trucking world. I have a 2001 2500HD with the 8.1 and Allison.

 

1. I noticed the fluid pan for the Allison has a drain and also an external filter. Is there an internal filter? If the answer is no, then to drain the trans without a flush of the entire system, then is all I have to do is drain the trans via the drain plug and change the external filter, right?

 

2. The truck as 4WD. I noticed one fluid check plug on the axle so I guess this is where I check and add fluid? I didn't see anyway to drain the axle so I guess you don't unless it needs repair.

 

3. The truck has electronic 4WD. I noticed on the transfer case there was an upper and lower plug. I guess you check the fluid at the top plug and drain at the bottom one? Sounds like a stupid question I guess. Actually another thing that isn't clear to me is do I have to ever change the transfer case fluid.

 

4. Back to the trans. I gues you change the external filter at the same time you change the fluid.

 

5. Differential. Is is ok to just pump the differential dry when changing the fluid or should the cover be removed and the rear end cleaned out?

[raventai]

1. yes there is an internal filter,it suposedly should not need service the life of the transmition ??? if u remove the plug and change the spin on filter u get about 2/3 of the fluid as there is about a quart in the pan that the plug does not get and there are many quarts in the tourque converter for more info see this thread and all threads linked from it http://www.gm-trucks.com/cgi-bin....4;t=176 if u do the 2/3 change on a regular basis then it is ok, allison says change the spin on at 5,000 miles and then filter+fluid every 50,000 for normal duty or 25,000 severe duty for complete directions read http://www.allisontransmission.com/documen....0EN.pdf

 

2. I dont have a 4 wheel but this should be in your owners amnual

 

3.yes and see above

 

4.yes

 

5. (rear diff) a guy on the diesel page pulled the cover and stated that the drain  did a good job of getting all the fluid  the drin plug is magnetic so it will pull all the metal out with it so u should not have to bothere with the cover (I dident)

[Kansas Kid]

1.  I think this was covered more then adequately by raventai

 

2.  Assuming you are talking about the front differential since you mentioned the 4wd.  It will have the fill plug you noticed, as well as a drain plug.  The fluid should be right below the bottom of the fill hole.  And yes it does need changed, which I would do after the truck has had around 500 miles of running in 4wd.

 

3.  On the transfer case, you are correct about checking in the top plug, and draining in the bottom one.  It does need changed as well, probably on about the same schedule as the automatic transmission.  Its easier to do it at the same time since they use the same fluid, and you will only have to get covered in the pink stuff once.

 

4.  Yep, and do not forget to take the magnet off the top of the spin on filter and put it on the new one!

 

5.  Just drain it out using the plug.