Some stats first: 2000 Excursion 7.3 4wd right at 423500 miles. Did the 6.0 cooler swap about 3 years ago. 9k miles since the last flush, using the Mark K. method.
Now for the long-winded explanation of the issue -
Two days ago on a short (less than 10 miles) trip I cruised off the highway down an exit ramp, slowed to merge at the bottom, and immediately felt that the transmission had slipped out of gear. I came mostly to a stop, started off and it wouldn't shift out of first. Since I had less than a mile to go I limped it the last little way in first.
First thing I did was check the fluid, it was about 3/4 of the way up the honeycomb in the hot section, so I added the less than half a quart of fluid I had with me. I was at that stop for about an hour, then came out to see if I could limp it home through the back roads. I started off and it shifted fine for the first 5 miles of back streets, then started "slipping" again. At that point I was playing with it and realized I could start out in drive (1st) , manually shift to second, then shift back to drive and it would hit 3 and 4. Had to do that sequence every time I came to a stop or had to slow for traffic.
When I got home I scanned for any codes and got nothing. I took it down the road about 4 miles to my mechanic to double-check that he wasn't getting any codes, nothing there.
That all took place over 3 or 4 hours, and anytime I let the truck sit and cool off for 20-30 minutes it would shift ok for the first mile or two and then back to the slipping routine.
So didn't do anything with it yesterday. Today I headed out to take it about 15 miles to drop off at the transmission shop, driving nice and easy on a cool day. Only had one slip issue the whole way, about 3/4 of the way there. Besides that shifted fine.
So I guess my question is, is there something simple I'm missing/not thinking about that would cause my issue? Or is it just time for a rebuild? I'm certainly not complaining about getting over 423k on this tranny, just want to make sure that I'm not missing anything.
I'll be talking to the shop in the morning once they have a chance to check it out.

 

My guess is that a seal has failed in the intermediate clutch. That will prevent a 1-2 shift, especially hot. When the trans is cooler the ATF is thicker and the seal can hold.

When you manually shift 1-2 the trans applies the intermediate band, which will hold when the intermediate clutch will not hold.

I think it's time for a rebuild.

 

Thanks for the input Mark. I figured it was toast, just double checking. This transmission, due to my ignorance, didn't get it's first flush until 363k miles when I stumbled across your procedure. Once it's rebuilt I'll be sure to keep up with flushing. Every 30k, is that correct?

 

That is my recommendation.

 

well, the good news is, you got 423K miles out of it. That thing doesn't owe you one red cent.

 

Yeah it had a good run. Now if the rebuild gives me another 423k that should be just about right...

 

I do not understand why but in my life experiences, rebuilt transmissions do not last very long.

 

huh...less walleye hunting and more trans hunting..just think how much more "tight lines" you'll get from finding the right trans shop

 

i have a question or 3 about transmissions, 2002 f250 4x4 , Seems mine is maybe slipping, as i accelerate i can feels i little pausing, Pulled my camper off to storage yesterday it was like i was pulling 10 tons rather then 3 tons!
so after i get the camper done, I went to leave the truck hesitated after dropping it into gear, then hit hard into 1st, shifted funny for a bit then stopped shifting hard , but would do the flutter thing again when accelerating!

Is there a way for me to test the transmission,
fluid is full and looks clear, does not smell burnt
could it be my torque converter is going bad?
can i just replace that , or should i look into a rebuilt?

 

Have you checked for codes?

 

Here's a update on my transmission issue - on Monday I stopped at the shop first thing in the morning and explained the symptoms etc. Shop owner calls me midday and says they can't get it to do anything except shift like it's supposed to. We talked, they were going to go drive it some more and see what happened. Called me this morning (Tuesday) and said still couldn't get it to act up. I went by at lunch and drove it for about 45 minutes around town, probably 20 miles, everything from stop and go to 65 down the highway. Zero issues. Shop guy said bring it back if it occurs again, wouldn't take any money for his time, wouldn't even let me leave some pizza and beer money. Just said remember him when I needed transmission work next time.
So , I don't have any clue what the issues the other day were. Is it possible some sort of debris got lodged somewhere temporarily and then moved on? Even though it's been less than 10k since last flush I'm considering doing one now just because. Or maybe that's a waste of $120 bucks of fluid. We'll see, but either way it's shifting fine with no issues currently. Weird.

 

My brothers E4OD started acting up,once in a while worked normally.Eventually puked all the fluids on the highway...Does not necessary mean that your's will crap out too..💩

 

no transmission codes!
but something is definitely going on!

 

I personally hate things like that, causes me headaches! works right , don't work right, just frikin break so i can fix it!

 

Here's food for thought, or maybe everyone except me already knows the answer.. the shop owner said he has seen similar things before and has a theory that it may be the throttle position sensor malfunctioning and sending wrong signals to the computer, thereby causing shifting errors. Or something like that. Anyone have any thoughts about that?