I have a stock 2001 Excursion, V10, 2wd, with the 4R100 trans. Today I started having a delay to shift from first to second and when it shifted, it shifted hard. I had to start letting off the accell when rpm got up around 2800 before it would shift. I nursed it home from 100 miles away. I have spent the afternoon reading post here about sticking 1-2 accumulator or possible broken spring. We are leaving on a camping trip in 5 days and need to get this fixed soon, as this is my tow vehicle.

I have read that the Transgo SKE4OD kit has everything I need to fix it, but haven't found one locally and don't want to trust shipping from an Ebay seller. Summit Racing has the E4OD HD2 kit in stock, and can get it overnight shipped on Monday. This kit has everything I need plus more.

Can I install just the springs and valve from the HD2 kit without using the included separator plate? I don't mind installing the plate if it will improve shifting but I don't want a hard shift all the time. Can the plate be installed without drilling larger holes? I basically want to install what will fix my problem and anything included to help the trans last longer without having a snappy shift during everyday driving. Thanks for any input

 

What engine is in your truck?

 

2001 Excursion, V10, 2wd

 

Your symptoms match a failing mechanical diode. Those were not supposed to be in gas versions of the 4R100, but I've heard of a handful over the years that have been confirmed to have one.

Usually, as it fails it drops small parts into the pan. It's probably worth dropping the pan to look for parts of the mechanical diode before going any further.

 

Thank you so much for replying Mark. I did a little reading on the mechanical diode this morning. It does sound like my symptom could fit the diode failure. At this point, I really don't know for sure if my trans has the mechanical diode or if it was built for a gas or diesel. I do know that it has been replaced by previous owner. I have no idea of when it was replaced. It has a Southland Rebuilders tag on it. They were Fords rebuilders in this area, not sure if nation wide. I would hope that they knew this was a problem and wouldn't rebuild with the diode. But who knows.

Is it still possible that the sticking 1-2 acc valve is the problem? The Excursion is my daily driver. My plan is to have the Transgo kit in hand when I pull the pan. If I don't see broken parts in the pan, move to the valve body. If there is pieces, the vehicle will just be down until its torn apart and fixed.

Edit:Checked tag on trans, build date code is BD-1B12. So the original build was 2001, Jan 12. That fits in the range of the mechanical diode.

 

It is possible that it's the accumulator.

 

Thank you Mark

 

Well I pulled the pan Thursday. Found no metal or broken parts, only a small amount of gunk on the magnet. I got the Transgo SKE4OD shift kit. I replaced the acc valve springs and 2nd acc valve. It made no difference at all. The valve was very hard to remove, the new steel valve didn't seem to stick going in. I read somewhere tonight that the valve should fall out on its own when the retainer clips are removed. I hate to take it to a trans shop or put a reman trans in it. I think I'm going to pull the acc valve body again and inspect it again. Anything else to look at more closely while apart?

 

Look at the accumulator. The valve must fall out under it's own weight or it's stuck. Yours was stuck and the new one probably is, too.

 

Thanks again Mark. Pulling the pan back off after work tomorrow.

 

I am in the learning stages of the operation of this transmission.
Since it seems to have the mech diode I would do the following.

1) Start engine. Put it in manual "2" and apply light throttle to get it moving, then drop it into manual "1". See if it downshifts and picks up speed. This verifies you have a 2nd gear via at least the band.

2) To determine if 2nd accum stuck or mech diode I would do this. Get two DMM (volt meters) and tap into the SS1 and SS2 (purple/orange) wires about 3 feet from the trans connector. That is the easiest point to get to. Put it in "D" and have someone watch voltages on the two meters. In 1st gear it will be around 0v on SS1 and around 14v on SS2. Apply throttle and when it shifts, if SS1 is 0v and SS2 is 0v then it is in 2nd (and mech diode is holding - GOOD). I would then declare the 2nd accum to be the problem. If SS1 is around 14v and SS2 is 0v then it is in 3rd and PCM skipped 2nd gear. I would declare the mech diode bad - RATS.

3) When you checked the 2nd accum valve did you CLEAN the valve first. This is IMPORTANT. If it had oil on it then the oil stiction could make it not fall out. If you hold the VB so the 2nd accum valve should fall out it may not due to the oil at the end of it holding it to the VB. Use a pick to break this stiction and see if it slides up/down after that.

Not an expert. Just saying what I would do before pulling the trans for a mech diode upgrade to sprag. I would do steps 1 and 2 and go from there.

Good luck. Hope you have nice weather for the camping trip.

 

Another way to check if it is the accum or mech diode is this:

1) Tap into SS2 (purple/orange) wire about 3 feet from trans connector. Make SURE you have the RIGHT wire. Run the tap wire into the cab. Connect another wire to ground in the cab.

2) Start engine and put in "D". Apply LIGHT throttle to get going in 1st gear. Then touch the SS2 tap wire to the GND wire and see if the trans shifts into 2nd using the mechanical diode.

 

So you are using a manual method to apply SS2 instead of the computer applying SS2. I'm sure I've missed something. How does that differentiate between the mechanical diode and the accumulator?

 

I was trying to see if it was doing a 1-3 or a 1-2 shift.

 

I think the only way you're going to find that out is with AE or the equivalent, looking at the real time gear ratio inside the transmission.