What trans fluid should I use?

[03WIDEMAX]

I'm getting ready to change the trans fluid on my 03 with 143,000m. I have an edge installed, but I use if for mileage mostly. The truck is stock except for the edge. I want to make my transmission last (who doesnt) so should I use synthetic? Do I change the internal filter too? I bought the truck with 130,000 so I don't have an in depth history. I know that it towed a fifth wheel camper. Oh, if I switch to synthetic do I need to flush the trans? I read the hoot method.

 

[BudTX]

With 143k on the clock, I would go ahead and change the internal filter as well as the spin-on. It is 'way past time if the previous owner never did it.

The owner's manual says that you don't have to change the internal filter unless the tranny is getting rebuilt, but I have had some experienced tranny guys mention that 50k is not a bad interval. The hoot method will be the way to go if you are going to change over to synthetic.

 

[stacks04]

i doubt synthetic will make it last longer at this point, but it does reduce heat and just flat works better. if you do it though it can get costly. i would do both filters and get them from the dealer or an allison dealer. also check the vendors here i'd bet they have them also.

 

[Wrecker]

I would use synthetic fluid, I would change both filters, I would not buy any filter from a GM/Chevy dealer. Allison is still the cheapest place to buy both filters, if not convenient, I'd buy the filters from me. I would refill with synthetic after dropping the pan to change the internal filter and change via the drain plug thereafter.

That's just what I would do.

 

[Pepperidge]

If you can find a shop with a BG machine...some of their machines will hold the line pressures of the Allison...they way I was told to tell is "if their machine can handle it it they have the adapter for the alli...(The BG rep is not supposed to sell them the adapter to the allison if the machine can't take the pressure...)