5R55E lock up - what controls it?

[markwillenbrock]

I have a 97 4.0 SOHC with a flashing od light. The transmission is running through all the gears, but won't lock up.

We're in the middle of a fuel shortage here, and I need those extra miles per gallon!

I'm guessing the lock up is electrically controlled, and that there must be a relay somewhere. Or does anyone know which wire controls the lock up on the plug that goes into the side of the transmission?

I'd like to be able to just switch it in and out until I can find someone here (Morocco) that understands these transmissions!

 

[papabluetexas]

trans not engaging.

Your problem is similar to mine. When you say the transmission goes though the shift gears do you mean that the shift lever can be moved to each gear. MY 2000 explorer does the same and I have no trans fluid flowing through the system at all. There is no click or actual movement of the transmission as far as I can tell. My car has a manual switch for 4x4 i do hear a click when moved from auto to low or high. Today I ordered more detailed trans repair manuals as I plan to fix this problem for between $100 and $1100, myself. I would do a quick check about 20min. Well, maybe longer to soak the connections with PB Blaster and let sit overnight Mine came loose right away. On your radiator you should have two metal lines running into (Drivers side top and bottom of radiator trans cooling tube). Hold the cooling fitting with a backup wrench and loosen the line with another wrench. If you have another set of eyes and hands have someone watch these lines while you start the vehicle and shift thru at least two gears. Fluid will come out at high pressure so have the person stand back or use protective eyewear gear, etc. Your problem may be a simple electrical connection but more investigation needs to be done. Le me know. I do have some diagrams on how to check the transmission range sensor etc.

 

[IZwack]

If the OD light is flashing, get the vehicle scanned for codes before you do anything else. That code should lead you towards the failing part.

 

[papabluetexas]

O/D light flashing maybe bad assumption

I assumed,and that's bad, that the vehicle is not able to move. If it does move and the OD lightis flashing park it and have it towed to the nearest repair station for anaylsis at least. If it does not move I know the situation you are in, towing costs $100.00, In New Jersey with transmission problems all you have to do is walk through the door of a repair shop and it's $2500 to start the paperwork. Anyway good luck. Like the previous post, running and that means going down the highway with O/D light flashing don't drive it.

 

[markwillenbrock]

flashing OD light

I think it's probably an electrical problem.

The Explorer moves and the gearbox works; if I disconnect the battery for 10 seconds the light stops flashing and the gearbox behaves normally, including lock up, for about 5 miles.

As it seems capable of functioning I don't see that there's much risk of damaging it by driving it (which I am obliged to do!) as my understanding is that when the od light flashes the transmission goes into a 'limp home' mode (hence the slightly hard shifts) to prevent damage.

The vehicle leads an extremely hard life carrying up to 7 people and their kit around Morocco.

A while ago it lost over run braking in 1st gear (1st still functions under power, but free wheels if you lift off). I'd assume that's an internal mechanical problem...

The light came on after about 200 miles at a steady 75mph on the autoroute.

I found that the line to (or from) the cooler was leaking, so repaired that by the side of the road.

The transmission level (I checked it carefully, priming the 'box) showed a correct full level but as it must have lost something I added 0.5 litre of Mercon.

Since then it's covered 600 miles plus, without incident but without lock up! I've changed the fluid, and have the filter on order and will do another fluid and filter change when it arrives.

I suspect that somewhere in the morass of wires theres a short. The Ex has been in deep water repeatedly, and been driven through lots of scrub and dunes. Visually, the connector on the side of the transmission looks fine.

I don't have access to a code reader here that will give me the transmission fault codes.

What I really want to know is what controls the lock up.

There has to be a wire, relay or something.

If I can find the wire, I'll rig a manual switch.

 

[gijoecam]

The ECU controls the lockup. It reads a whole host of sensors and sends the apropriate signals to the transmission. There is no one particular wire I know of that ultimately controls the lockup. It's very possible that it's NOT locking because it can't. The system has obviously detected a faul for which the engieners here in Dearborn have determined it best that the transmission NOT lock. Fix the problem, and it'll work the way it should. Trying to make an electronically controlled transmission manually-controlled is just asking for more problems.

 

[markwillenbrock]

Thanks for the advice Gijoe!

My problem is that North Africa is a long way from Dearborn, so we have to be creative to keep things running. No scanners, no transmission shops, and very few parts. I'll be pleasantly surprised if the filter I ordered turns up!

My (vague) understanding is that when the trans. is locked up in od, it creates very little heat or slip.

Since 90% of my driving is at a steady 60mph+, I hope you can see why I'm hoping there's a solution with a DIY lock up.

Interestingly, I got the od light off and normally functionality back yesterday by driving up a steep hill in '1'! Didn't last, though.

The ZF trans in my old Land Rover is one of the best bits of the vehicle - still untouched after 250,000 miles - but I don't think there's much in the way of electronic control.

 

[papabluetexas]

I have very limited knowledge but I believe your problem is with The Transmission range sensor. I guess Michigan" Mr. DearBorn didn't notify you. TSB # 962410. I have basic information but no detailed diagram. On your vehicle do you have Manual O/D switch? I believe the TSB was to replace your module with a new electronic controller module. If that is the case you should be able to enable or disable OD at the input directly at the transmission. Will send you more information as I do more research. It is probably more complicated than that but we need not overlook the simple things.

 

[markwillenbrock]

Papablue, I don't think the car has had any recall work done - not even the chains, which I have on order from the US. I hope they arrive here one day...

Where is the transmission range sensor? My gut feeling is that I have a chafed or damaged wire somewhere.

My car is a UK spec 4.0sohc with a floor shift PRND21 and a tiny OD switch on the side of the shift lever, which inhibits the od.

As I don't have the ability or shops to carry out complicated repairs, simple ones are where I have to start!

Not far from me there's an Explorer running a Mercedes 3 litre diesel; just outside my apartment there's another one that's 'dead'.

I'd like to keep mine alive!

 

[gijoecam]

I have very limited knowledge but I believe your problem is with The Transmission range sensor. I guess Michigan" Mr. DearBorn didn't notify you. TSB # 962410. I have basic information but no detailed diagram. On your vehicle do you have Manual O/D switch? I believe the TSB was to replace your module with a new electronic controller module. If that is the case you should be able to enable or disable OD at the input directly at the transmission. Will send you more information as I do more research. It is probably more complicated than that but we need not overlook the simple things.

TSB 96-24-10 does not exist. Can you please provide a description of the bulletin? It may have been superseded by another TSB, but I can't seem to locate one with a description that might apply.

We could guess at the symptoms all day long, but the best way to diagnose it is to get the codes scanned. The transmission is telling you it knows the EXACT problem as indicated by the blinking OD light.

As for the actual wiring, it appears that the PCM ultimately controls all of the transmission functions. There is no one wire for 'overdrive'.... the PCM controls the solenoid for the torque converter clutch solenoid and the coast clutch solenoid, but beyond that, I honestly have no clue what the PCM actually does to modulate them.

Also, the problem could be caused by any of a host of sensors reading out of their range... ECTS, TPS, MAF, IAT, heck, even an errant brake light input could cause an issue and prevent it from going into OD.... Without knowing the code that's stored, it's a guessing game at best.

IMHO, trying to manually lock and unlock it is playing with fire.

 

[papabluetexas]

SB Number:962410 NHTSA Number:50909 TSB Date:November 18, 1996 Date Added to File:June 17, 1997
Failing Component:
Power Train:Automatic Transmission
Summary:
Transmission - e40d - 4r70w - 4r44e - 5r55e - new digital transmission range sensor - diagnosis service tip.
I am aware of the dangers of jury rigging. I am not condoning it. Just giving information that may help. By the way on this forum there are members that have tried this with the o/d circuit. In gears 3 and 4 you can manually manually make the trans with a switch go into o/d (providing all other controls are working). In gears 1 and two other vacuum circuits prevent any overdrive.

 

[markwillenbrock]

Well, when my lock up worked, it used to lock in 2nd as well. It was very obvious in low range with '2' selected.

Today we've fitted a new filter and gasket. There was about 1/4 inch of black sludge in the bottom of the oil pan. Bizarrely, the od light stopped flashing just before the fluid change.

There's a flare on the 1st-2nd or 2nd-3rd change now, that was absent with the od light flashing.

I'm getting interested in how to try and change the oil - does anyone have any thoughts on this?

I'm keen on but frightened of taking a cooler line off and filling from the dipstick with the engine running (I think).

Advice please!

 

[papabluetexas]

The answer is on this forum, just do a little searching it's a neat fluid change that clears everything out of the torque converter. Once I get my explorer back on the ground and moving, without being pushed, I will definitely try the full clean flush. Regards,

 

[markwillenbrock]

To be honest, I worried about damaging the trans (more!).

The post I saw inferred you could take off one of the cooler lines whilst filling from the dipstick.

Elsewhere, it seems that the fluid comes out of the cooler lines at pretty high pressure.

I'm concerned that relying on gravity to replace fluid that's being pumped out under pressure is going to cook something.

But I do want to get rid of the black muck that's appeared since the transmission started acting up!

 

[ALARMIST]

I understand your not working under the best of circumstances there.
re: lock up, it sounds like some here have done it with an external input.
My experience with a totally different brand, was that in some cases the lock
up solenoid would work with external power and or ground thru a switch.
(later model) In other cases it was looking for a specific pulsed signal provided by the trans control computer.

re: cooler lines, I have on occasion purged all of the old fluid as follows.

use 5 gal pail or similar, you can disconnect the cooler line at an accessable
location (radiator) route the open line to the pail with any scrap hose to contain the fluid mess ( depending on which you choose, supply or return,
fluid might flow from the direction of the line, or from the cooler).
Extend both if not sure.

Starting with the trans full, and the lines routed to the pail.
Start the engine, shift to drive for 5 or 10 seconds, back to park.
evaluate how much fluid you dumped to the pail, try for 1 or 2 quart(litre)
at a time- trans prob. holds 10-14 quarts, add the same amount of new fluid
to the dipstick fill tube 1 or 2 quarts(litre) each time.

This only takes about 5 minutes to do- reconnect the line- verify trans- is full
when done, amount removed in pail should equal amount new added.

Good luck

 

[gijoecam]

SB Number:962410 NHTSA Number:50909 TSB Date:November 18, 1996 Date Added to File:June 17, 1997
Failing Component:
Power Train:Automatic Transmission
Summary:
Transmission - e40d - 4r70w - 4r44e - 5r55e - new digital transmission range sensor - diagnosis service tip.
I am aware of the dangers of jury rigging. I am not condoning it. Just giving information that may help. By the way on this forum there are members that have tried this with the o/d circuit. In gears 3 and 4 you can manually manually make the trans with a switch go into o/d (providing all other controls are working). In gears 1 and two other vacuum circuits prevent any overdrive.

Thanks. I'll see what I can scrounge up in the morning.

As for the problem, excessive black goo in the bottom of the trans pan is never a good sign.

The codes need to be scanned. That'll pinpoint the problem in a minute. Without that code, it's all one big guessing game at best. There's easily 30 things that could be the cause of the problem, and there's no way to know what that problem is without the DTC.

 

[gijoecam]

SB Number:962410 NHTSA Number:50909 TSB Date:November 18, 1996 Date Added to File:June 17, 1997
Failing Component:
Power Train:Automatic Transmission
Summary:
Transmission - e40d - 4r70w - 4r44e - 5r55e - new digital transmission range sensor - diagnosis service tip.
I am aware of the dangers of jury rigging. I am not condoning it. Just giving information that may help. By the way on this forum there are members that have tried this with the o/d circuit. In gears 3 and 4 you can manually manually make the trans with a switch go into o/d (providing all other controls are working). In gears 1 and two other vacuum circuits prevent any overdrive.

Found it! But it doesn't apply here.... It was only applicable to the 97 model year vehicles... His is a 96. It was a how-to bulletin with instructions for using a particular Rotunda test cable for troubleshooting the DTRS on a 97 model year vehicle. It doesn't give any indication of what the failures could be.

Beyond that, a bad DTRS would not cause a the trans to not go into overdrive. It's used when starting as the neutral safety switch, and tells the PCM what gear has been selected by the manual lever (or in the OP's case of a RHD vehicle, the console shifter). The Explorer doesn't have a 3rd gear position on the shifter.... Drive, 2, 1. If the overdrive lockout button had been selected, it would be indicated as such by the light on the instrument cluster. It's not going to ba a bad DTRS causing it...

The trouble code needs to be read, plain and simple. Anything else is just a guessing game. Any shop with an OBD-II capable scanner should be able to pull the code without a problem anywhere in the world.

 

[markwillenbrock]

Hurrah! I've found a scanner (only 320 miles from home). I'll get the codes read later today, with luck.

I'll flush the transmission as well. How much fluid should one have on hand?

Motul (the best I can find, apparently Mercon compatible) is $12 a litre!!

 

[markwillenbrock]

Well, I have a code: P0741

The computer says it's excessive slip when the transmission knows it should be locked, and says the fault is electrical or hydraulic.

I knew all that!

The shop recommends - a new gearbox ;-)

Not that they can get one.

Anyone any the wiser?

 

[markwillenbrock]

Well, I'm not sure I'd recommend the running oil change. We did it very carefully, 5-10 second bursts, and adding the same amount of fluid that was pumped out, and working the selector through PRND21...

It's now sometimes reluctant to take up drive, particularly in reverse.

This morning it was running on 3 speeds only, I think.
After a brief climb to 4,000 feet it's settled down a little. Manual engine braking is back in '2' and it will shift to od (though obviously not lock).

So, I have to find another transmission. In the meantime, it's back to the Landrover and it's tough ZF auto!