[71mustang06]

is any one having shift problems with the 5R55S, I have noticed a few problems like no RPM drop from 1rst to 2end gear under low throttle driving and today under 75% throttle 2end gear hit the rev limiter for a few seconds before shifting to 3rd. I like to down shift to help with braking in rush hour or in coming off of a heavy speed run. Am I not supposed to Manually downshift my car? under 100% throttle the trany shifts perfect with RPM drop and punch in every gear. any input would help thanks

[05stanggta]

do you have an aftermarket tune on the car?

[05stanggta]

because if you do i would get in contact with whoever supplied your tune. my brenspeed tune changes how my transmission shifts, however i havnt had any problems like that with it

[71mustang06]

nope, stock tune, I do have single chamber flowmasters and a cold air intake installed.

[mustang fanatic]

I have an auto with bama tune. It has never hit the rev limiter. Also don't down shift manually to much. Just use your brakes they are cheaper. If I manually shift then this is what I go by when downshifting manually. From 5th to 4th 50mph. From 4th to 3rd 40mph. From 3rd to 2nd 20mph and from 2nd to 1st nothing faster than 15mph.

[71mustang06]

any one know the power train warranty on the mustang? is it 36k?
its just that I don't aspect any shifting problems on a car with 20k on the OD.

[71mustang06]

*BUMP* is any one else having these problems>?

[qwik48r]

I dont know the 5r55... but if it is designed the same as most auto's, it could either be low line pressure (which could be anything from the front pump being damaged by the verter, or round out or blow by) or a failing (as in heat scored, worn down) second gear band and drum.. manually downshifting gets all sorts of yay/ney... but in my experience, down shifting an auto isn't great because your using the friction materials to match the revs, i.e one part is speeding up the other by means of friction... NOT great for lengevity unless the trans was designed to do so (racing trans with heavy duty frictions/high line pressure)

does it sound like its banging the rev limiter then catching the gear so to speak? dont mean to worry you but, sounds like a slipping 2nd gear.

[71mustang06]

yes , today it hit the rev lim for a few ticks then banged 3rd

[qwik48r]

ouch... do you have any mods? as in cai/tune? or gears?

[mustang fanatic]

Yea that doesnt sound good. Take it to the dealer and see what they say.

[71mustang06]

no everything is stock sept for flow masters and cold air intake

[71mustang06]

but it doesent do this all the time, its intermittent

[qwik48r]

like when the tranny gets nice and warm?

[mustang fanatic]

Got this off of modularfords.com

Some of you have probably read my previous thread describing a 3rd gear failure in my 5R55S automatic transmission with only 9,500 miles. After doing considerable research using my Ford Service Manual DVD and pestering several transmission builders here is what I have determined. The root cause of the 3rd gear failures is the seal on the intermediate servo piston. By not continuing to drive the vehicle with this failure, the band is most likely not damaged. I spoke with a couple of transmission techs at 2 different Ford dealers and both said they replace 2 to 3 of these intermediate servo pistons a month for this exact reason.

So, I pulled the pan down on my 5R55S. No metal or clutch material and the fluid was not burnt. That indicated the failure may be as simple as a repair and not an overhaul. I investigated the possibility of replacing the intermediate servo piston with the transmission in the vehicle. This is not possible as the transmission is too close to the body. So I removed the transmission. Now here is where transmission shops offer differing opinions. Some shops say this CAN NOT be done without completely disassembling the transmission because when the servo piston is removed, the intermediate band anchor will fall down in the case. Yet others say they replace these components frequently without ever disassembling the transmission. I figured I had nothing to loose. I pulled the intermediate servo piston snap ring, cover, piston/seal assembly and spring. If you will look at the attached picture (the one that is very bright), you will see in the servo piston bore the anchor is still visible. This is good news as it would indicate that the band is not broken and the anchor did NOT drop down when the servo piston was removed. There is also a picture of a new servo piston, with the cover, assembled ready for installation in the case. Lastly, take a look at the piston I removed. Notice on the Small OD a 1.5" section of the sealing lip is completely gone. I now have the intermediate servo piston assembly reinstalled back in the transmission case.

While the transmission was out, I am replacing the TSS sensor as a while back I had a P0715 DTC for that sensor. I cleared the code and it never came back. But to replace the Input turbine speed sensor the transmission must be removed, now was the time to replace the sensor. Tomorrow I will adjust the intermediate and overdrive bands.

How much has this venture cost me - other than a whole lot of my labor:

(1) Intermediate servo piston (1L2Z-7D021-CA) $16.73
(1) Seal - intermediate servo piston cover W702969-S300 $2.60
(2) Band adjustment locknut (XW4Z-71000-AA) $3.60 ea.
Total parts investment $26.53

Now while the transmission is out, I am going to take advantage of this opportunity to install a 2,800 RPM stall converter. Keep in mind this is a daily driver and not a track vehicle.

In conclusion, will this fix my 3rd gear problem? Won't know for sure, but for less than $30 in parts I couldn't justify a complete overhaul yet.

Moral to this story: If your transmission looses 3rd gear don't continue to drive the vehicle.

[qwik48r]

hmmm... thats not comforting at all.

sounds like an after market servo would be a good idea to give some more clamping force.

[71mustang06]

Originally Posted by qwik48r like when the tranny gets nice and warm?

no when its in the middle of being cold to normal operating temp, about half way to norm

[qwik48r]

transmission dont slip when cold...

change your fluid/check level and post a pic of the color.

[71mustang06]

can't theres no trany dip stick

[qwik48r]

uhhh... really? thats awful fucked up of Ford....