Overdrive/5th gear Missing in Action

Rrusse11 · **Posted:** Sun Jun 07, 2020 6:57 pm

So we set out yesterday for the first test of my CRD towing my 1200# teardrop. Up into the Appalachians here in rural central PA. First 100 miles over hill and dale no problem, then without warning the tranny jumped out of 5th into 4th, I was mostly running between 60-65, ~ 2krpm.
Motor jumped up to 2500, and obviously a bit noisier, I slowed down to 55mph, found a place to pull over.
Stopped the car, restarted, now it's going into 5th overdrive lockup.
It didn't last though, 15 minutes later it happens again.

At a reduced speed we made it to our destination, engine light on. In the morning we set out, now of course feeling nervous about the trip, but running fine for the first hour, guessing here until the tranny got good and warmed up. Of course it happens again, so with motor performing perfectly well, transmission now in 4th,
we turned tail and made our way back home without incident, albeit a bit slower than I would have liked.

So what's going on? 5th gear/overdrive are still there, just not staying in the right gear. Is it the torque
converter giving out or do I need an upgraded spring kit? Nothing seems to be "broken", no funny clanks or
grinding, just won't stay in the right ration. I'm suspecting pressure somewhere in the control aspect of the
tranny, and I cheerfully admit to knowing next to nothing about how an automatic works.

Any input greatly appreciated, there is a good tranny shop locally, what should they be looking for/doing
to fix it? I'll spring for a torque converter et al if that is the culprit.

Cheers!

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Dumb question: have you checked the transmission fluid level?

Do this with the transmission well and truly warmed up (±20 mins. of driving). On level ground, put the shifter in 'P', let the KJ idle for 1 minute, check the fluid level, wipe dipstick, re-check.

Note that the CRD dipsticks are calibrated about 1.5 to 2 quarts too low. If it's showing full, you're still well below capacity.

layback40 · **Posted:** Sun Jun 07, 2020 8:50 pm

casm wrote:

Dumb question: have you checked the transmission fluid level?

Do this with the transmission well and truly warmed up (±20 mins. of driving). On level ground, put the shifter in 'P', let the KJ idle for 1 minute, check the fluid level, wipe dipstick, re-check.

Note that the CRD dipsticks are calibrated about 1.5 to 2 quarts too low. If it's showing full, you're still well below capacity.

& they like to be well & truly full !
I wonder how long its been since the trans oil & filters were changed?
Would be interesting to know what code(s) caused the MIL.

Rrusse11 · **Posted:** Sun Jun 07, 2020 9:37 pm

Thanks for the suggestion gents, I did check it a month or so ago, and it was well above the line. I'll certainly have another look in the morning, and see if the problem occurs without the trailer in tow. I do have a filter kit, and I'll grab some ATF, it certainly wouldn't hurt to change the fluid. Oil and fuel filters recently replaced, ,1000 miles ago.

WWDiesel · **Posted:** Sun Jun 07, 2020 10:45 pm

If the transmission fluid temperature increases, the TCM will lockout 5th gear and overdrive and even 4th gear trying to lower the oil temperature.
It happens especially when pulling a loaded trailer in hot weather.

Warm Oil temperature between 40° F and 80° F -
Normal operation (upshift, kickdowns, and coastdowns) - No EMCC

Hot Oil temperature between 80° F and 240° F
- Normal operation (upshift, kickdowns, and coastdowns) - Normal EMCC operation

Overheat Oil temperature above 240° F or engine coolant temperature above 244° F
- Delayed 2-3 upshift
- Delayed 3-4 upshift
- 3rd gear FEMCC from 30-48 mph
- 3rd gear PEMCC above 35 mph
- Above 25 mph the torque converter will not unlock unless the throttle is closed or if a wide open throttle 2nd PEMCC to 1 kickdown is made

Rrusse11 · **Posted:** Mon Jun 08, 2020 7:51 am

"If the transmission fluid temperature increases, the TCM will lockout 5th gear and overdrive and even 4th gear trying to lower the oil temperature.
It happens especially when pulling a loaded trailer in hot weather." WWdiesel

Well those were certainly the conditions, it was in the 80s. So what to do?
There was no change whatsoever on the engine temperature gauge. How do I increase transmission cooling?
Thanks WW!

flash7210 · **Posted:** Mon Jun 08, 2020 8:58 am

WWDiesel wrote:

If the transmission fluid temperature increases, the TCM will lockout 5th gear and overdrive and even 4th gear trying to lower the oil temperature.

Good call.
Trans overheating is the most likely cause.

What does EMCC mean?
I've seen the term in the manual but couldn't find a description.

flash7210 · **Posted:** Mon Jun 08, 2020 9:20 am

Rrusse11 wrote:

How do I increase transmission cooling?[/size][/b][/color]

Install an aftermarket transmission cooler.
I have one. Zip tied to the inside of the grille.

Rrusse11 · **Posted:** Mon Jun 08, 2020 10:17 am

flash7210 wrote:

Rrusse11 wrote:

How do I increase transmission cooling?[/size][/b][/color]

Install an aftermarket transmission cooler.
I have one. Zip tied to the inside of the grille.

Flash,
Some quick research and that looks to be the ez and relatively cheap fix. I'll replace/flush tranny fluid, check all connections for leaks, and install an additional cooler. That should deal with it.
The overheating diagnosis has to be spot on, that's clearly what was happening. Lots of hills, high temps, and the time frame when the problem started to kick in. Whether or not the tranny pump itself is a bit suspect is a potential issue. Obviously that and an upgraded TC is a much bigger $ job.
I too am curious about EMCC?

iakj11 · **Posted:** Mon Jun 08, 2020 10:42 am

EMCC = Electronically Modulated Converter Clutch

TKB4 · **Posted:** Mon Jun 08, 2020 10:59 am

When you change the transmission fluid make sure you ONLY USE ATF4 fluid. This cannot be stressed enough.

Also save yourself a lot of hassle with next change by installing a transmission drain in the pan while you have it off. Its just drilling the right size hole and bolting the drain in costs $15-$20.

WWDiesel · **Posted:** Mon Jun 08, 2020 11:06 am

flash7210 wrote:

WWDiesel wrote:

If the transmission fluid temperature increases, the TCM will lockout 5th gear and overdrive and even 4th gear trying to lower the oil temperature.

Good call.
Trans overheating is the most likely cause.
What does EMCC mean?
I've seen the term in the manual but couldn't find a description.

Electronically Modulated Converter Clutch (EMCC)
This transmission uses an Electronically Modulated Converter Clutch (EMCC) that provides for partial engagement in third, fourth, or fifth gears.
It also provides for full torque converter clutch engagement when certain operating conditions are met.

As to adding an extra transmission oil cooler, see this:> viewtopic.php?p=928484#p928484

10 Plate Stacked Oil Cooler mounted in opening below front bumper.

Rrusse11 · **Posted:** Mon Jun 08, 2020 12:52 pm

WW,
Thank you sir! Now there's a fix.
Cheers!

TKB4,
And thank you sir for the drain tip and the AT4 spec.

Many thanks to all who replied so promptly, I feel much better about the issue knowing what is happening, and how to deal with it.

WWDiesel · **Posted:** Mon Jun 08, 2020 12:56 pm

Rrusse11 wrote:

WW,
Thank you sir! Now there's a fix.
Cheers!
TKB4,
And thank you sir for the drain tip and the AT4 spec.
Many thanks to all who replied so promptly, I feel much better about the issue knowing what is happening, and how to deal with it.

FYI: All the parts for adding an extra transmission cooler can be sourced online at Summit Racing or Jegs. :wink:

Rrusse11 · **Posted:** Wed Jul 08, 2020 11:15 am

So I took my Jeep along to a highly recommended tranny shop where the first response was a transmission cooler would help. After convincing them that I wanted a better fix, and was willing
to pay for it, I've now got an upgraded torque converter, a HD cooler, a trans go spring kit, and service.

I had them mount the cooler in the front bar and fitted the alloy mesh myself. The word was that the transmission, as per the previous owner's claim, had recently been rebuilt, and overall was in good shape.
The proprietor highly recommended a HamptonPrecision TQ, and the oversized tranny cooler, and after I
asked him to place it in the bullbar, he took me seriously about doing a thorough rehab.

The spring kit/TQ converter has transformed the tranny, shifting is positive, mpg has increased, and now
the turbo is working a LOT better. Heading out next week again with the camper as a test run.

Just shy of $2100 for all the work and parts, about what I'd budgeted for a rehab. I'm confident that the proprietor means it when he said, "Bring it back if you have any problems."

Rrusse11 · **Posted:** Sun Sep 20, 2020 8:53 pm

Update on my tranny problems, see above. So after a new torque converter and tranny cooler, we set out again with the teardrop. 2 hours on the road and oops!, limp mode again. Back to the shop where they came good. A couple days of research by the owner on a pro forum and he gave me a call. He offered to do a valve body and solenoid pack for parts cost, no labor charges. No payment until I was happy with it.
Three days later I went in to pick it up. Over the next three weeks we put about 1500 miles on it, close to a 1000 towing the trailer. Zero problems. I gave him $636 for the parts and shook his hand. Nice to deal with a business that cares about their work, and reputation, old school.

Since then I've been driving it for short hops and around town more, getting a better feel for the vehicle.
Tranny is now very defined on the shifting points, up and down. I tend to turn the od off for putting around,
slipping in to neutral at the lights, though it does help with torque converter clunk if I shift to N while still rolling.

Hitting the highway or country roads, run it up to 45/2200rpm or so before hitting the OD button back on and let the overdrive do its thing. For additional engine braking from speed I turn it off.

Rotated the tires at 4k a couple of days ago and coming up on an oil change at 5k soon. Had to replace LH rear tail light, there was some overheating and a loose plastic bit from somewhere internally got stuck to the brake/tail light bulb. Replaced a couple of the twist in bulb holders, a new TYC light from RockAuto, and we're motoring on. Learning to love the little truck, next spring I'll look into a TB job and a set of glow plugs.
Motor's running great, 19-20 around town, ~25mpg hwy, 21-22 with the little trailer. Drives great with the load, np pushing 70mph. Got a bit of an exhaust leak, I suspect the flex pipe, turbo is decidedly noticeable with a bit of push on the throttle. No loss of power, but you certainly hear the boost kick in.

Needs that fixed and give the underbody a squirt of fluid film before winter.
Cheers all!

Overdrive/5th gear Missing in Action

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