shifting problem after 4r55e rebuild< could it be the servo? | Ford Explorer Forums - Serious Explorations

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shifting problem after 4r55e rebuild< could it be the servo?


Well-Known Member
January 13, 2007
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Year, Model & Trim Level
1996 sport
Hey guys,
I broke my intermediate band in my 4r55e a while ago, i decided to pull the trans and do a rebuild. I replaced the intermediate band, od band, frictions, steels, gaskets, seals, and a new torque converter, new ford OD and intermediate servos, plus a new cooler.
well the truck is back on the road, but im having a shifting issue from 1st to second, sometimes 3rd back down to second, it feels like im having problems with the intermediate drum, it flares from 1st to second, and it feels like it;s having a hard time starting and finishing the shifts, from 1st to 2nd and 3rd to 2nd.
Before i broke the band i always had a pretty bad flare, partially hard throttle from 2nd to 3rd, i replaced valve body with a central valve bodies unit, which works amazing but still a flare,( donny at central valve bodies is awesome)
So im wondering if the new problem, and old problem are related? The only thing i can think of is when i pulled the OD and Intermediate servos out of the case the two springs sizes are differrent. The OD servo spring was smaller and was a green color, the intermediate spring was much larger and thicker and was yellow. Even though the ATSG 4r55e book states that both springs are the same part number, i put the two different springs back in. after the rebuild and noticing the shifting problems i went to ford, and their computer says that both servo springs are the same, the smaller green spring. Could the thicker spring in the intermediate servo be causing my problems? like i said earlier it's much heavier and taller than the green spring. If it helps here is a list of what i have done
-adjusted both bands twice, once during rebuild and once after rebuild after driving around. Ten foot pounds, used my inch lb craftsmen torque wrench set at 120 in lbs, then backed both adjusters exactly two turns, the book says both back off two turns but i think i saw a post by BB that says the intermediate is 2.5 turns? torqued lock nut to specs.
- replaced od and inter. servos with new ford parts, servo covers on my 4r55e are AB on both covers
- Mobile one atf
- new pan filter, plus new auxillary mobile one 301 oil filter
- New B&M super cooler
- checked fluid numerous times and am about to check it after this post, running in idle, operating temp, level service
- replaced all steels and frictions, and bands with kit from CT powertrains
- Torque converter from advance auto

Im hoping its the servo spring that is causing this problem, i have two on the way from ford and plan on replacing both the od and int springs. Im still very very new to auto trans, so any help would be greatly appreciated. thanks guys- Dan

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Hey Don, when I replaced my intermediate and OD servos the springs were different. The OD servo spring was softer than the intermediate servo spring. I use the existing springs and just changed the servos and servo cover o-rings.


what transmission did you replace the servos in? a4ld?

Don, i replaced the servos and o-rings in the servo covers in a 4r55e...If your rig has over 100k, I recommend replacing them. Its so much easier to take them out with the cat off. I had both gaskets leaking so it was a no brainer for me to take it out. Just make sure you use PB blaster on the bolts. PB is the best!

Don, which EPC is in the valve body right now- red or green?

i replace both servos and seals during the rebuild, but i will probably pull them out again to take a look. I have a green epc which is correct for my year

Is the EPC new? I know you're supposed to replace your EPC with a new one, but I reused mine and it solved my trans shifting issues. I'm wondering. When you rebuilt the trans, did you inspect the front pump and/or replace the pump gears? If I were in your shoes, my next step would be to pressure test at the test ports...