Need advice--torque converter lock-up issues

thefunk · **Posted:** Tue Aug 25, 2015 10:10 pm

A couple of weeks ago my transmission started acting up. 2005 CRD with EGR delete and Nick's stock ECU flashed in. Vehicle had F37 when purchased 4000 miles ago. 68000 on vehicle now.

While driving through town transmission shifted from 3-4 or 4-5 VERY firmly a couple times, followed by gear and torque converter lock-up hunting that finally resulted in going into limp mode and a code thrown for something like "unable to control input speed". Can't remember the code number, but it pointed to a bad turbine sensor. Replaced that sensor, and thought it was licked, but a few days later transmission acted up again. Fault is hard to define since it isn't always happening (do they ever?). Here's my best attempt at description:

1. When "cold" (just started) transmission will not go into 6. It will stay in 5, which means about 2900 rpm at highway speed.
2. Once engine thermostat is at operating temp (needle at center of gauge) it will shift into 6, but not stay locked up.
3. Worst area of powerband is between 60 and 75, torque converter will lock / unlock about once every second. Taking it out of OD and then putting it back in seems to help clear it and it will quit hunting for a while. Judicious use of throttle can help it calm down also. If a hill is approached in 6 locked it will pull the hill, then near the top it will downshift and begin the lock/unlock routine.
4. Cruising at speeds over 75 seems to keep the transmission locked up and working properly.
5. Accelerating from 50 (shudder check) results only in lock/unlock routine, no shudder at all.
6. Possibly related but unknown--when accelerating out of a slow speed turn (like turning at a stop light or stop sign) a shuddering sensation can be felt, sometimes, unknown if this is transmission or U-Joint issues. Checked all drivelines and they feel fine. Rear suspension arms also appear good. Some up-and-down play at rear diff ball joing / boomerang but no side play.

I tried adding more ATF+4. By using the Park-Reverse-Neutral-Drive-Park check method I discovered that the sump was painfully low. I have added 2 quarts since, it is now filled well above the max hot line with no change. I'm thinking that maybe PO had it serviced at 60k before they sold it and local quickie lube didn't know what they were doing.

Possibly wrong filter? Or something a Transgo kit would fix? I was planning on going into the transmission and building it "right" (TC, pump, shift kit, etc) but doing it at the end of the year when I wasn't broke and harvesting a crop. This isn't the best time to be dealing with this issue, but it has to be reliable for the wife to drive since we live an hour out of town. Any advice is appreciated.

flash7210 · **Posted:** Wed Aug 26, 2015 8:03 am

It sure sounds like a torque converter problem.
If adding more fluid didn't fix it and replacing the input speed sensor didn't fix it, then I'm not sure what else there could be.
You could try draining the fluid and changing filters. Its possible that the last time it was done they did not use ATF+4.

Other thoughts:

Cold transmission-
Yes, this transmission will not shift into overdrive with TCclutch lockup when cold. But you should only be noticing this during the winter when its 40 deg F or below. Should not be happening now during the summer.

Transmission shifting-
The 545RFE transmission behind the CRD engine is a 5 speed transmission. Not a 6 speed.*
Shifts patterns are like this:
With O/D-on: 1st,2nd,3rd@ ~20mph, 4th@ ~33mph, 4+TC lock@ 51mph, 5+lock@ 61mph.
With O/D-off: 1st,2nd,3rd@ ~20mph, 3+TC lock@ ~38mph.

You could try driving around town with O/D-off to see if that changes anything.
Then, when you get up above 50mph, turn O/D back on to force it into 4th+lock. Just to see what happens.

What you are describing with the shifting sounds like the TCclutch is being applied at the right times but is failing to hold. The TCM senses this through the input speed sensor and then commands the TCclutch to disengage.
This is different from shudder because during shudder the TCclutch is fully applied and holding but then starts to slip under hard acceleration or when pulling a heavy load up a hill.
When you are cruising at a steady speed, the TCC appears to hold because you are not demanding any additional power from the engine.
Shudder only occurs at times when the TCC is applied (see shift patterns above).

So, I would start with a transmission fluid and filter change.
The TransGo kit is a good idea and easy to do while you are changing the filters but probably will not fix this problem.

*Technically, the 545RFE is a six speed. But it has two 2nd gears, one of which (2') is only used as a passing gear. I doubt you will ever notice when it shift into 2'

thefunk · **Posted:** Wed Aug 26, 2015 11:58 am

My only other thought besides TC would be that the dealership didn't install the new pump with the F37 update. But naturally there's no way of knowing that until I pull it all apart, as as long as it's apart it's getting a new TC anyway. They didn't put an update sticker in the engine compartment either so odds are they did nothing but the TC, and maybe nothing but ECU flash.

Good thing the wife is patient I guess...

flash7210 · **Posted:** Wed Aug 26, 2015 12:21 pm

When my F37 was done all they did was the TC and reflash. No pump.

100,000 miles later everything still going strong.

pjigar · **Posted:** Wed Aug 26, 2015 11:39 pm

I was watching 545RFE rebuild video from MrTranny and he said that if a spring in the pump body breaks then it will hunt for lock up at around 60 MPH. You seem to have the same symptom. How many miles you have? May be its time to fix the pump and add a new TC while you are there, and may be a complete rebuild.

WWDiesel · **Posted:** Thu Aug 27, 2015 6:36 am

There are some bores and plungers in the front pump housing that wear over time. They help control the lockup of the clutches in the torque converter. :roll:

This information was given to me by a good friend who has been in the transmission overhaul business all his life and still is... When he installed my Suncoast TC he also installed a new design front pump assembly and a Transgo kit....

Sounds like you need a new front pump assembly....? :wink:

Mountainman · **Posted:** Thu Aug 27, 2015 11:29 am

I'd be looking for a newer hemi trans at the junkyard that has upgraded bits that are weak on our CRD's. That way you pay for a cheap used transmission and get upgrades at the same time. Of coarse junkyard stuff is a gamble... Someone did a write up, and I think they swapped in the control module as well with the tranny, and it was in a CRD. They said it worked well. Oh, you could also get the TC with it and have a cheap hemi TC with the deal, hopefully. That's what I'm going to do when I eventually kill mine.

thefunk · **Posted:** Fri Aug 28, 2015 10:16 am

Well, bit the bullet and started ordering parts. Ordered a billet Torque Converter from Florida Torque Converters and a Transgo kit. Transmission guy says that if the pump hasn't been updated he can just replace the valve in the pump, apparently that was the weakest part of the design. Same thing with the non-annodized valve body, it can have the worn bores re-sleeved. All in all it will be painful but not criminally expensive, and I'll know that the transmission is right and won't have to worry about it when I get the coin together for a high performance program. A couple seals are weeping so it will be good to get those replaced too.
I was leaning towards putting in a Hemi TC but Keith at GDE and the guy at Florida TC's both poo-poo'd the idea. Since I didn't want to mess with any factory "quality" Daimler Chrysler torque converters again, the aftermarket unit got the vote. More money, but I shouldn't have to pull the trans again hopefully EVER.

Need advice--torque converter lock-up issues

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