98 E40D w/ Mobil 1 Synthetic ATF

[jscott]

Background:
98 F-150 w/ 5.4L and E40D auto transmission. Currently at 87500 miles. I changed the original ATF at 30K and installed a new Motorcraft filter. I did drain the TC and was able to get all but about 1.5 qts out of it. It holds 16qts total. There is no scheduled interval for changing the fluid in the E40D in my truck. I have towed some, but not a whole lot.

How long can I run this fluid? It seems to "bump" a little when shifting into O/D under moderate power. This seems to be more common when the truck is completely warmed up. Would an analysis determine if the fluid were worn/depleted? I have heard of similiar problems with the 4R70W (lighter-duty transmission) in this truck, which were corrected by a transmission fluid flush.

Thanks in advance!

 

[unDummy]

Fluid needs to be changed regularly regardless of type used. Synthetics give better performance at higher/lower temps than regular mineral atf. A used oil analysis of the ATF will show the wear in the fluid. Stock OEM atf filters are a joke. A good canister aftermarket fullflow or bypass filter will allow you to use the fluid longer.

Its impossible to get 100% of the fluid without a rebuild. Even though you drained the TC/pan, there was probably enough old fluid throughout the transmission.

I'd say that you are overdue(mileage wise) for another ATF exhange. Toss in a bottle of lubegard platinum/black and stick with the Mobil 1 during your next drain/refill.

This transmission has tremendous aftermarket support. There are solutions for every issue if correctly diagnosed. Start with Ford TSBs(and talk with a transmission specialist). Then search the internet for valve body upgrades, shift improvers, TCU reprogramming, solenoid/pistons/gasket/oring upgrades.

 

[jscott]

Thanks for the response. I forgot to mention one point earlier... I added AutoRX per directions about 7k ago. The issue I mentioned was present before and after the AutoRX.

I did change the fluid/filter over the weekend and will send off a sample. The fluid looked good to me before the change, but in comparission to the new, there was a noticable difference in color.