99 tranny slipping into 4th

[nashman918]

i have a 99 explorer sport with the 4.0 ohv engine and auto tranny. lately i've noticed that if i'm getting on it a little bit or if i'm going up a hill, it will slip slightly when going into 4th gear. the fluid is at the correct level and other than that it shifts fine. i'm just wondering if i should be concerned with it or if i should just run it.....thanks for any input

 

[Glacier991]

The OD band slipping is a problem for these trannies. Candidly I think the frying of the servos and their ultimate hardening plays a role, but it is nigh on impossible to replace them in vehicle.

Your slipping transmission in OD is is something to avoid.... it will shorten the life of the trannie. Fixes? Try having the bands adjusted. That will help somewhat. On heavy duty uphills step on the accelerator until it downshifts to 3rd and then select D until you are on a more level surface. Your RPM's will jumnp about 700-800 to about 3,000 but that's a comfortable place for your engine.... and transmission. Depending on mileage, an EPC replacement and or shift kit (a place where the pressure riser on the Superior kit might be a godsend) might be a good idea. Check out the 5R55E VB Rebuild Diary in the stickied section for some idea what I am talking about.

I have nursed a yearand a half out of an A4LD with 220K miles on it by following these "rules".

 

[BrooklynBay]

There is also another option that you could do. I did this on my A4LD a number of years ago. They sell an upgraded servo, and matching cover that is larger than the stock servo. The more surface area, the more apply pressure (hopefully) due to more fluid surrounding the servo. I think they now have even bigger servos as an upgrade that are available. I saw a bunch listed in a parts manual. I think the springs are still different. Some are soft, and other ones are firm. Maybe this could affect the apply pressure as well.

 

[Glacier991]

Servo replacement "in vehicle" is an exercise in complete frustration.

 

[BrooklynBay]

I did it to mine when I rebuilt it. I didn't attempt it while it was still on the vehicle. My vehicle doesn't have that metal heat shield over them. The newer ones have it. I was interested in getting it, but the places that sell transmission parts don't stock it, and can't order it either. The books just list a Ford part #, but no aftermarket part #.