Tranny clunk when cold

[Martin Olson]

I have a 2001 Ford Sport Trac. I bought it a couple of years ago with 139K. It's up to about 145K. The transmission tends to slip when cold. You put in D and slowly rev the engine and it catches. Occasionally it will catch hard and make a major clunk. Usually when it does a hard clunk, the OD light comes on. It also tends to not catch in reverse.



Once warm it works fine. Fluid levels are fine.



I know many people have had this. What causes this? Did you get it repaired or did you buy a rebuilt transmission or a used one. Any opinions on this?



Thank you.

 

[Mark K 2]

Try a flush first.

 

[EddieS'04]

You might have the valve body gasket leak. Early tracs had that problem. There is an upgrade kit for that. Might want to have the whole valve body and solenoids replaced.

You can DYI fpr around $600 apraoximtly....



Is you OD light staying on??? That can be a sign of more problems.

 

[Martin Olson]

The OD light stays on if it clunks to hard. If you turn off the engine and back on again it disappears.

 

[EddieS'04]

If the OD light comes on at all. Time to have it profesionaly looked at.

If your lucky it will only be the valve bady issue.

Do a search on this site. You will find that the most common problem.

 

[Martin Olson]

Contacted the original owner and I bought it with 132k. He told me he never had the tranny serviced so I am going to start there. On a basic transmission service what is everyone replacing. Obviously the filter and the pan gasket, but what else?



Any kits to recommend. I have a 2WD with the 5R55E tranny.

 

[Martin Olson]

One other question. I saw a video from 1AAUTO talking about the valve body gasket replacement. How far should I take this? A simple fluid change. How hard is the valve body gasket job? It looked pretty messy but not too hard. I am pretty handy.

 

[Richard L]

Not hard to remove/replace valve body gasket.....The only trick is that the valve body contains numerous small check-balls (and often small springs) that must be returned to replaced in the exact same location. So remove the valve body carefully and take photos of the location of all the check-balls and springs.



One of the more common problems with the Gen1 Sport Trac valve body is that the gasket mating surface may not be perfectly flat and that causes the gasket to leak. An old trick is to put a piece of 1000 grit abrasive paper on a 1/4 inch thick sheet of glass and sand the mating surface of the valve body to ensure it's flat. You will be able to tell when the surface is flat because the surface will appear the same lightly sanded texture all over...no shiny or dull spots.



To prevent loosing any of the check-balls or springs while reinstalling the valve body, you can use a little dab of Vaseline to hold the check-balls in place. Once the engine is started and the tranny warms up the Vaseline will melt harmlessly into the fluid.



...Rich

 

[Martin Olson]

To do the valve body how long a time are you looking at? The tools did not look to complicated.

 

[Richard L]

If you have a lift and a catch basin to catch the fluid that will pour out of the pan when you remove it, the job is a lot easier. Attempting to do this without a lift always makes it more difficult since jacking up the truck and putting it on jack stands takes up time.



Assuming this is your first time doing this, you want to go slow and carefully....checking and double checking that you did not forget something.



With a lift, drain pan and all the right tools....it could be done in less than 2 hours.



If you are doing it without a lift, but you have everything else....probably 3 hours....maybe 4 hours if you are old with bad knees and a bad back like me.... most of that time would be wasted with me just trying to get up and down from under the truck. :grin:



...Rich

 

[Martin Olson]

I have ramps which should give me enough room to be comfortable. I fully expect to be wearing a fair amount of tranny fluid when done.

 

[Martin Olson]

I am going to start off with a nice flush. I am going to replace the filter and the gasket. Is the OEM the best filter or are the aftermarket filters better? I am using the truck as a daily driver and I don't do anything crazy with it.



Once I see where I am at, I will probably do the valve body soon. I really appreciate the wisdom Rich.

 

[Martin Olson]

I am going to start off with a nice flush. I am going to replace the filter and the gasket. Is the OEM the best filter or are the aftermarket filters better? I am using the truck as a daily driver and I don't do anything crazy with it.



Once I see where I am at, I will probably do the valve body soon. I really appreciate the wisdom Rich.