I have a 98 Explorer Limited 4x4 w/ 4.0 sohc. The problem started about 2,000 miles ago. The truck has 88,000 miles on it . When slowing down to a stop after it is good and warmed up it clunks and you can feel a slight bump also. I feel like it happens when it downshifts from 2nd to 1st b/c it occurs at about 10 mph. Any ideas? Thanks

 

Does it klunk during acc too? Have you checked your U-joints?

 

no it only does it when slowing down. Havent checked u joints, b/c its only on deceleration. If its a u joint it should "clunk" on acc also right?

 

yes

 

When I had my transmission rebuilt I had a problem with the tranny shifting from 2nd to 3rd when it was cold.

It would delay shifting for some reason.
The computer would register a shift error
the O/D light would start flashing (indicating tranny shift error)
I would drive it with the O/D Light flashing

When the O/D Light was flashing I would have EXACTLY the same symptoms you described (clunk when tranny shifted back to first while deccelarating)

I took it back to the shop and they tolld me this:

When the computer sees a tranny error and starts flashing the O/D light It also increases the trannsmission fluid pressure in the tranny to a higher limit. this was causing the "clunk" while downshifting.

I fixed the Upshift problem by having my fluid flushed completely.




Is your O/D light flashing? If NO then
Does your O/D Light work? If YES then
Have you had your trannsmission fluid flushed and the pan dropped and the screen checked to see if it is clogged? If yes then

I think your trannsmission might not be regulating it's fluid pressure correctly. Maybe the pressure sensor is bad or clogged and your computer is reading it incorrectly. You should have a shop hook a pressure gauge up to the cooler lines and make sure it is not to high.
The problem is that any shop you take it to will tell you you need a rebuild

 

Fluid and filter has been changed and o/d light does work. It has never flashed,neither has my check engine light come on. Took it to local dealer b/c Its barely in warranty from when I financed it 3 years ago and they "said" there were no codes and they had know idea what was wrong with it and wanted me to pay 296.00 to tear it down to find the problem. So after arguing I picked it up.
I will check into having the pressure checked. I'm a boat mechanic, so is there any way I could test the
pressure sensor?

 

I think they check the pressure by disconnecting both cooling lines and hooking up a pressure guage. But since the cooling circuit has a automatic hi pressure bypass It won't really tell you if it is too high I think.


You could always get the ODB-II software and scanner (about $300) it lets you monitor and diagnose the computer. It probably shows you what the computer is reading.

Do you know if any work was done on the trannsmission before. Maybe someone put a shift kit into it.

I bet if the pan was dropped the sensor is in an accessable location

 

Does your transmission have a filte? I thought most of the four wheel drive models had only a screen

 

Yeah it has a filter I've changed it before myself. No it doesn't have a shift kit it just started this a few thousand miles ago. Talked to a mechanic frien and I'm taking it to a tranny shop he recomended.

 

Clunking on these models is caused by two things.
The first is that the rear driveshaft splines need lubricating. If you remove the rear mounting bolts (they are torqued WAY high) and pull the shaft out of the boot, you will see the splines. If they are dry, lube them up with some good grease.
The other cause of clunking is the torsion bar pads. These pads are in the housings at the end of the torsion bars and are made of teflon. They wear out after awhile causing the clunking sound. Remember that you must undo the torsion bars to replace them which requires special tools.