Transmission fluid exchange


Well-known member
Apr 20, 2004
Northern Kentucky
I think I am going to let Aamco do their 4x4 service. It includes changing the diffs and the transfer case and use the machine to cycle through 100% of the transmission fluid.
They are going to use all Mobil1 products to refill for about $269.
I could do the diffs myself no problem... but I want to try out their transmission service. Truck has about 147,000 on it.
I have read all the posts about refilling the transmission and just had a quick question.
I am not sure exactly how the machine works and they are already closed so I can't call and ask. When they hook up the machine to the transmission they should run the truck and shift through all the gears just like you are refilling it right? Seems obvious that they would, I just want to make sure.


Active member
Oct 7, 2008
eugene, OR
I would not recommend doing it with 147,000 on the transmission. I would just do it in stages, change the fluid three times. When you put new fluid in a higher mileage auto trans the dex is a cleaning agent and will knock a bunch of stuff loose(varnish...etc). That is why it is good to change the fluid three times spaced apart by a couple weeks, so you get all the stuff that comes loose from the newer dex.