Transmission Service

[Willy G]

I recently hit 25,000 miles on my 2007 LBZ 2500hd, daily driver and I don't tow. I contacted my dealer to have the transmission serviced. I requested to have both filters (internal & external) replaced and new fluid. They said that I didn't need to get the internal filter changed. Are they correct? Maybe I am going overkill, but I want it done right! Suggestions....

[DmaxMaverick]

Allison spec's the internal filter to be changed only during overhaul. If it needs changed, the tranny needs an overhaul. No need to drop the pan (it has a drain plug). Diligent service isn't overkill. More power to ya.

[Mark Rinker]

I have had good luck 'draining and filling' the ~7quarts that come out of the Allison at each oil change interval, spinning on a new external filter.

Based on your usage description, you might go every other oil change interval. (We tow heavy and constantly.)

You have to watch the 'kids' at JiffyLube-type oil change places, they will throw out your magnet, that has to be switched from filter to filter.

[dually2002]

I changed the internal filter at about 35000 miles. The old one looked very clean and you could see the actual color of the filter no black stuff. I only change the spin-on filter now because it looks like it does most of the filtering. Change it about every 15000 miles cause it so easy to do.