5R55E shift problem

[greg s]

I have a 97 explorer with the 4.0 sohc and 5R55E transmission with 225000 miles on it. It is well serviced and has had numerous updates and last year I replaced the valve body with a rebuilt one from Central Valve body which has all the Sonnax updates as well. This week a problem with how it shifts started. If I am driving below 45mph it shifts thru all the gears and into o/d fine, but if I am accelerating harder to get up to 55-60 mph it seems like it slips going into o/d. It will go thru the first 4 gears ok then when it goes into o/d the rpm jumps way up so I let off the gas and turned of o/d. I have been driving it with the o/d off and it seems to work ok. The oil is clean and doesnt smell burnt. I pulled the codes and the only one I get is P0732 gear 2 incorrect ratio. Also when I did the KOEO test I constantly get the P1703 brake switch out of range code no matter if I tap the brake pedal or hold it down during the test. Any ideas of what to check?

 

[PopRichie77]

Well, replace the brake switch. As for the trans could be the OD band out of adjustment or starting to break or the servo needs replaced.

 

[2000StreetRod]

overdrive or torque converter lock?

. . . If I am driving below 45mph it shifts thru all the gears and into o/d fine, but if I am accelerating harder to get up to 55-60 mph it seems like it slips going into o/d. It will go thru the first 4 gears ok then when it goes into o/d the rpm jumps way up so I let off the gas and turned of o/d. I have been driving it with the o/d off and it seems to work ok. . . I pulled the codes and the only one I get is P0732 gear 2 incorrect ratio. Also when I did the KOEO test I constantly get the P1703 brake switch out of range code no matter if I tap the brake pedal or hold it down during the test. Any ideas of what to check?

If the brake pedal position (BPP) switch is closed the PCM will not lock the torque converter. Are you sure the torque converter is not locking instead of overdrive not engaging? In the 5R55E overdrive is engaged to obtain the second speed. Does your cruise control work? If it won't engage that indicates that the BPP switch is on.

 

[greg s]

So I had the chance tonight to drive it on a open back road to try and figure out what is working. Sometimes it seems to shift to quick from 1st to 2nd and it drops out of 5th gear as well. So after my test driving I picked up some additional codes, P0731, P0732 and P0735. None of the codes triggered the o/d light to come on and flash though.

The brake switch still test as "out of range" so I will pick one up and swap that out, but the cruise control does seem to work in all gears. So I don't know if the brake switch could be a problem.

I am thinking it is the bands or the servos that apply them. I am going to adjust them to see if it changes things. If it improves the problem I will look at replacing the servos with the ones that have O-rings to compensate for wear.

If it doesn't change anything I guess I will drop the pan and valve body to check things out. Any more help would be greatly appreciated.

 

[2000StreetRod]

ss3 failed off?

According to my 5R55E ATSG manual the diagnostic trouble codes for shift solenoid 3 failed off include: P0731, P0732 and P0735. The symptoms are no 2nd and 5th speeds.

 

[greg s]

I recently replaced the brake switch that is attached to the master cylinder because it was leaking (recall). I believe this switch is the one that disengages the cruise control.

I still have an original valve body with all the solenoids, so I can try swapping that out as well.

Does anybody know if the computer goes into a different program when you switch off the o/d? It seems to work ok with the o/d off and wondered if it has a different shift program for towing.

 

[2000StreetRod]

safety pressure switch

I recently replaced the brake switch that is attached to the master cylinder because it was leaking (recall). I believe this switch is the one that disengages the cruise control.

The hydraulic pressure switch is a safety backup in case the BPP switch has failed. You should be able to just tap the brake pedal enough to activate the BPP switch to disengage the cruise control without actually creating any brake pressure in the lines. It takes 5 to 10 lbs of brake pedal pressure to open the hydraulic switch and remove power from the servo clutch.

 

[greg s]

So is the BPP switch just the switch for the brake lights? Or is there another?

 

[2000StreetRod]

dual section switch

So is the BPP switch just the switch for the brake lights? Or is there another?

The switch has two sections (DPDT). One section is for the stop lamps and the other section connects to the GEM, ARC module, shift lock actuator, clutch pedal position switch/jumper, RAP module, 4WABS, speed control servo and PCM.

 

[greg s]

OK then it must switch to ground? Mine only has 2 green wires attached to it.

 

[2000StreetRod]

hydraulic vs brake pedal position switch

OK then it must switch to ground? Mine only has 2 green wires attached to it.

I think you're referring to the hydraulic brake pressure switch which should have a LG/RD wire (goes to fuse 13 in the central junction box) and a BK/YE wire (goes to speed control servo) connected to it. My comments referred to the brake pedal position switch.

 

[greg s]

No I was looking at the switch on the brake pedal. It looks like the typical ford brake light switch they have used forever. It just has two wires attached to it. I looked it up at RockAuto just to make sure and thats what they show as well. Its like $4.

 

[2000StreetRod]

1997 vs 2000

Apparently there has been an electrical change in the brake pedal position switch between 1997 and 2000. I found a 1994 wiring diagram that shows the stop lamp switch with only two wires (a LG/RD and a LG). I apologize for the confusion.

 

[greg s]

No problem. Its weird that its just a std switch and the brake lights work properly but the computer sees it as "out of range". Going to pick up one this afternoon and adjust the bands to see what happens.

I was reading that when you turn off o/d it obviously stops 5th gear engagement but it also provides engine braking I believe by applying the coast clutch in 1st-4th. Just wondering if that would mask any syptoms as it seems to drive ok with the o/d off but seems to have problems in 5th gear and others when o/d is on.

 

[greg s]

Also I read some where that when adjusting the bands it may be better to only back out the bolt 1-1.5 turns instead of 2. Anybody do this before with improvements?

 

[greg s]

I took care of the brake switch and adjusted the bands per Ford. On mine it was 2 turns out for the od and 2.5 turns out for the intermediate. I drove it a few days but have seen no change, it will sometimes have 5th gear at low (-40 mph) speeds but none at higher speeds. I cleared the codes and P0732 & P0735 came back.

How do you know if a band is broken?

I guess my next step would be to drop the pan and valve body to check the gasket and solenoids.