Escape torque converter lockup?

[ErnieX]

My son's 2005 Escape appears to be having a problem with the torque conv. lockup being stuck. Car stalling when comes to a stop, but idles fine in park and neutral. Starting off like it's in high gear. Had this problem on another vehicle and was able to unplug the lockup solenoid for a temp. fix. No flashing OD light.

Is there a lockup solenoid that can be unplugged for temp. relief and drivability just to be able to get it to a trans shop to check out?

Thanks in advance.

EE

 

[imp]

My son's 2005 Escape appears to be having a problem with the torque conv. lockup being stuck. Car stalling when comes to a stop, but idles fine in park and neutral. Starting off like it's in high gear. Had this problem on another vehicle and was able to unplug the lockup solenoid for a temp. fix. No flashing OD light.

Is there a lockup solenoid that can be unplugged for temp. relief and drivability just to be able to get it to a trans shop to check out? YES! You may disable the TCC by several means. Best is to have wiring diagrams, to determine exactly which wire from the computer turns on the TCC solenoid; that wire may be pulled free of the computer connector, or cut in-line somewhere convenient. All the solenoids are fed through a connector, so unplugging that will disable the whole damn transmission. Having disabled the TCC solenoid, the computer will probably "throw" some sort of warning; however, the vehicle may continue to be driven safely forever if you like, with a disabled TCC clutch. After all, we drove yesteryear's automatics forever without such clutches, so why not now? Fuel economy will drop perhaps 4 or 5%. I drove my '04 Explorer from Laughlin, NV back to Missouri with a non-functioning TCC clutch, against the dire warnings of the Ford Tech. who "read" the code, replaced the solenoid module, and all is well again! imp


Thanks in advance.

EE

 

[PopRichie77]

There is danger of the trans over heating if the TC does not lock up. Cars of the past without lock up torque converters had larger converters and had air cooling to prevent over heating. Under normal driving you can get away with the TC not locking, but heavy throttle and city driving and hills will send the temp up, the oil slippage in the small converters generates a lot of heat.

 

[ErnieX]

Thanks for the reply, Imp and Pop. Guess he'll be making a trip to the trans shop to get it checked out. We're three hours apart so hard to diagnose over the phone.

EE

 

[imp]

There is danger of the trans over heating if the TC does not lock up. Cars of the past without lock up torque converters had larger converters and had air cooling to prevent over heating. Under normal driving you can get away with the TC not locking, but heavy throttle and city driving and hills will send the temp up, the oil slippage in the small converters generates a lot of heat.

Sorry, but without some documentation of what you're saying, I don't buy it totally. Today's transmissions have far better cooling provisions provided to begin with. Yes, given very severe driving conditions, lots of heat is generated. But, given everyday driving of moderate severity, like towing, especially with O/D locked out, which prompts TCC to UNLOCK often, quite a bit of driving is done with the TCC NOT ENGAGED.

What if a guy is, let's say, towing something, and NEVER exceeds around 35 mph (totally possible, right?); his TCC will NEVER HAVE ENGAGED at all. So, why doesn't he destroy his transmission? So, no, I don't buy it. Also, given, I drove 2000 miles with NO LOCKUP, through mountainous terrain, some over 7000 feet altitude; the trans. is still operating well today, a year later.

One other consideration: Guys who install HIGH-STALL speed converters, thereby confounding the PCM with appropriate TCC lock-up scheduling; their transmissions continue to work, too (how long? No idea!). imp

PS: Air cooled torque converters were used universally (by Ford) through the 50s, but disappeared altogether with the introduction of their first big-block (FE) V-8s in 1958. After that, cooling was achieved by submersion of heat exchangers inside the car's radiator.

 

[PopRichie77]

I didn't say that you couldn't drive with the TC not locked, but trans temps will go up. With normal driving conditions there should be no problem. When I had a TC lock up problem I towed thousands of miles with no lock up, had to because I was far from home, also when I took the trans apart I saw no damage from heat, but the fluid was very dark and it had been recently changed. All 5 speeds worked perfectly just no lock up. I had no temp gauge at that time. When you lock out OD, the torque converter stays locked much more than it does in OD. This is one of the reasons for not towing in OD. I tow a 4,000+ lb. RV trailer with my Explorer, I have a trans temp gauge and an indicator for TC lock up. Also 2 stock trans coolers. If I tow in OD the first thing that happens when it starts pulling harder is the TC unlocks, trans temps will go over 220 degrees, I try to keep it below that. When towing with OD locked out the TC stays locked much more of the time and trans temps stay below 190 degrees, cooler if air temp is 70 or below. As soon as the TC locks trans temps start to drop down from 220 degrees. When you go down hill and take your foot off the throttle, the TC unlocks, trans temps go up again and if the hill is long enough it will go over 220 degrees again. I try to keep temps below 190. TC will lock in 3rd gear also and I sometimes manually shift from 4th to 3rd so that the TC will lock and keep temp down. The 5R55E will shift to 3rd gear at 35 miles per hour and under light throttle the TC will lock up. The TC in a C4 is much bigger and they were ran with the same HP that the SOHC 4.0, there is more surface area to dissipate heat.
How hot can trans fluid get before it will cause damage. I have tried to find an answer to this question but can't? I do know that it will boil.

 

[imp]

The TC in a C4 is much bigger and they were ran with the same HP that the SOHC 4.0, there is more surface area to dissipate heat. Your tow requirements are pretty tough for a small-engined, heavy to begin with, vehicle like Explorer. Surface area undoubtedly has a lot to do with heat dissipation, but the original idea of cooling TCs only with outside air was abandoned; it just wasn't that efficient. The reason is simply that liquid/liquid heat exchange involves higher specific heat coefficients, mainly. I like your idea of an indicator for TCC condition. I have toyed with disconnecting PCM control of the TCC to a manual, or even vehicle-speed switch, thereby leaving the TCC ALWAYS engaged, except for slow-down/stop conditions. Negatively, this would confound the PCM, and throw codes. Let the transmission down-shift bring about necessary torque, to hell with the fuel economy factor of the TCC. After all, we do OK with 5-speed manuals, w/o slush-coupling, no?

How hot can trans fluid get before it will cause damage. I have tried to find an answer to this question but can't? I do know that it will boil. Can't give you a definite number here, but I HAVE seen ENGINE OIL in big diesels running on dynamometer test stands exceed 280`, even as high as 300+`, but this was considered extreme. 'Course, the biggest consideration, after ruin of parts susceptible to high-temp. degrade, like clutch linings, bands, is the FLASH point of the fluid, or some component in it. Fire would be the final ruin! My gut guess in your case is that 220` will not quickly destroy any component in your trans., but will degrade the fluid beyond a doubt. I worked in an oil seal molding facility in which petroleum-based oil was used as the heat-transfer medium to heat molding presses running fluid temp 360`, so obviously, this was below boiling and flash points. imp

 

[PopRichie77]

We are kind of off the original subject, but I have tried the switch to keep the TC locked up and the PCM does throw a code and the trans goes into limp mode. Not a good thing because it now starts off in 3rd gear. Mine doesn't seem to affect the engine power but some do.
Your right air cooling went out a long time ago and had no bearing on the original question.
If the Escape PCM is similar to the Explorer, there is no easy way to keep the PCM from trying to lockup the TC so that it doesn't throw a code.