5r55s learns bad habits, harsh shift, after rebuild | Ford Explorer Forums - Serious Explorations

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5r55s learns bad habits, harsh shift, after rebuild

Netra

New Member
Joined
June 26, 2019
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City, State
muskegon
Year, Model & Trim Level
2004 Explorer
2004 Explorer 4WD. Very strange problem with trans after a rebuild by trans shop. I later found out, they were not reputable. Can't take it back again, they won't work any more on it and we are in litigation.

Trans originally had overheating and blown OD gears. I think the shop took the good parts remaining, plus unknown parts, and built a good unit. Except, here is the problem:

Immediately after a ECM KAM (keep alive memory) clear, the trans shifts like butter. Runs very nicely. Everything works fine. However it proceeds to learn a harsh 2-3 shift, which seem to get worse. Throws no codes and has no other issues. After 300+ miles the 2-3 shift becomes quite harsh and unacceptable. Reset the ECM again, and this process is repeated.

Your thoughts are appreciated! Worried I need to completely replace this trans.
 



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Have you tried cleaning the mass air flow sensor?
 












The pcm uses a few different sensors including the maf to determine shift strategy. I'd try giving it a clean, can't hurt and is easier than going to court.

Transmission shops can be shady though, and I can understand your frustration. Do you have a parts list / work they did?
 






The pcm uses a few different sensors including the maf to determine shift strategy. I'd try giving it a clean, can't hurt and is easier than going to court.

Transmission shops can be shady though, and I can understand your frustration. Do you have a parts list / work they did?

If you unplug the MAF and go for a short drive the transmission will shift very harshly. Have done this with two different vehicles to confirm
 






Was able to clean the MAF (with the correct MAF cleaner) but could not detect any change in the transmission shifting.

I found this post which may fit my issue: Ironing out Ford 5R55N/S/W clunks and bumps | Search Autoparts
It discusses 5r55 harsh shifting issues related to rebuilding a 5r55n/s/w with the wrong OD planetary gear set. However, there is no way to tell without disassembling the trans. Since I have no idea what gear set the rebuilder used, and I can't depend on getting honest info from him, I am in a bit of a pickle.

Has anyone ever heard or experienced this problem with the wrong OD gear set?
 












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