Good morning/afternoon all.

Like many others, I’ve been reading and searching the forum for several weeks. I just picked up a 2005 LLY LT 4x4 Crew a few weeks ago and couldn’t be happier with it. Now I’m just trying to get all of the maintenance in order so I can continue to enjoy the truck without any serious problems.

I have 2000 miles on the clock today and I plan to change my fluids and filters this afternoon if I could get some advice on the following shopping list.

10 quarts Mobile1 15w40 Diesel oil
Mobil1 M1-303 or is it M1-301 oil filter
8 quarts of Mobil1 75w 90 Diff fluid (front and rear)

This is all I have for now, is there anything else at all I should change?

Should I change the Allison fluid, filter or both? If so, what filter/fluid is needed?

Thanks! I appreciate any help I can get.

Jeremy

I just did my first oil change on my new dmax. Probably do the front and rear difarential before too long.

It is the mobil 1 M1-303 filter. I tried to get one several times at the local autozone with no luck so I got the ac delco pf2232 and delo 400.

I am wondering the same on the tranny.

Jeremy

You are supposed to change out the tranny filter at the first oil change, you don't need to change the fluid. - look at this tsb...

SMU - Revised Maintenance and Lubrication for Automatic Transmission Service Interval/correct Filter to Replace #05-00-90-005 - (May 26, 2005)

Revised Maintenance and Lubrication for Automatic Transmission Service Interval/Correct Filter to Replace

2001-2006 Chevrolet Silverado

2001-2006 GMC Sierra

with Allison® Automatic Transmission

This bulletin is being issued to revise the first automatic transmission service interval and specify what filter to replace in the Maintenance and Lubrication sub-section of the Service Manual. Please replace the current information in the Service Manual with the following information.

The following information has been updated within SI for 2001-2004. If you are using a paper version of this Service Manual, please make a reference to this bulletin on the affected page. The 2005 and 2006 Owner's Manuals have also been corrected.

The first automatic transmission service interval is at the first maintenance service performed on the vehicle. At that time, change the external spin-on filter only.

At every 83,000 km (50,000 miles) (normal service) or every 41,500 km (25,000 miles) (severe service), change the external spin-on filter and fluid. The sump filter is to be changed only during an overhaul.


- jeff

Check out the Allison FAQ (look for the link in the Allison OEM thread). GM recommends changing the spin-on every 7,500 miles. I bought a 6 pack of Baldwin oil and tranny filters to get the discount and just have the spin-on changed everytime I do the oil.

There have been discussions about switching to synthetic too early. You want the engine to break in before switching. The question is where is that point. I am waiting for 10K to switch. I did a 1K, 3K, and 6K change using Delvac 1. At 10K I'll switch to Amsoil. I figure with <5K per change and a good quality filter, I have no risk of undue engine wear versus synthetic and the insurance that the engine is fully broken in, just in case that does matter.

I don't believe Mobil 1 gear oil is not approved by GM for the rear locker. Eaton does support it but they don't provide the warranty work. If you have the locker, you may want to consider the extra cost of GM grape juice for the rear. For me, the time between diff fluid changes is long enough that the cost difference isn't worth the risk.