TC shudder before lockup? Slip?

Mountainman · **Posted:** Fri Aug 17, 2018 12:33 pm

My jeep shudders, no doubt about it. But, I realized it has the same feeling around 45 mph long before the TC locks. Could that be transmission mounts letting things flop around under load? U joints are all new.
This has persisted with 2 different transmissions, both with New style pumps.
I have shudder after lockup under high load at the typical place/speed.
Soon to add all of the upgrades, but maybe I'm also having slip do to lack of pressure?

flash7210 · **Posted:** Fri Aug 17, 2018 12:53 pm

Try driving it with OD-off to see it that makes a difference.
With OD-off the TC will lockup at about 40mph.

WWDiesel · **Posted:** Fri Aug 17, 2018 1:33 pm

The TC clutches are partly locked up at times, and fully locked up in 4th & 5th gears.
So what you may be experiencing is more than likely TC clutch slippage or shudder in 4th gear. :roll:

Time for a SunCoast?

From 545RFE Manual:
The clutch can be engaged in second, third, fourth, and fifth (if applicable) gear ranges depending on overdrive control switch position. If the overdrive control switch is in the normal ON position, the clutch will engage after the shift to fourth gear. If the control switch is in the OFF position, the clutch will engage after the shift to third gear.

The TCM controls the torque converter by way of internal logic software. The programming of the software provides the TCM with control over the L/R-CC Solenoid. There are four output logic states that can be applied as follows: ² No EMCC ² Partial EMCC ² Full EMCC ² Gradual-to-no EMCC

Note: If you want a copy of the 545RFE manual, let me know, I can email it to you as I have it in a PDF document. 462 pages...

Mountainman · **Posted:** Fri Aug 17, 2018 1:55 pm

Thank you both! Now I understand.
PARTIAL EMCC Partial EMCC operation modulates the L/R Solenoid (duty cycle) to obtain partial torque converter clutch application. Partial EMCC operation is maintained until Full EMCC is called for and actuated. During Partial EMCC some slip does occur.
It goes on to say that this partial mode is usually just with light throttle, which explains why when I WOT I don't feel any shudder until full lock. And the OD off explains the rest. So, I haven't lost my kind and it is shudder at 45ish. One problem is a lot better than two! :pepper:

Mountainman · **Posted:** Fri Aug 17, 2018 2:14 pm

Oh, I do have a suncoast, but I'm pretty sure my problem is that my front pump is pre 2013 upgrades. I'm just going to get a new pump and install all of the transgo and sonax
Upgrades. Not doing this 4 times, 3 is enough! I thought my 2013 mopar remanufactured transmission with updated front pump would do the trick, wrong. #2 transmission also has updated front pump, but it also must have been pre 2013 upgrades as well, actually I know it was pre 2013 as I bought it around then from a lost member who didn't have the transmission worked on at all for years.

WWDiesel · **Posted:** Fri Aug 17, 2018 2:22 pm

Mountainman wrote:

Oh, I do have a suncoast, but I'm pretty sure my problem is that my front pump is pre 2013 upgrades. I'm just going to get a new pump and install all of the transgo and sonax
Upgrades. Not doing this 4 times, 3 is enough! I thought my 2013 mopar remanufactured transmission with updated front pump would do the trick, wrong. #2 transmission also has updated front pump, but it also must have been pre 2013 upgrades as well, actually I know it was pre 2013 as I bought it around then from a lost member who didn't have the transmission worked on at all for years.

That's a real BUMMER! :banghead:

Third time's the charm! :roll:

Sounds like you may have some low line pressure issues?

Mountainman · **Posted:** Fri Aug 17, 2018 2:32 pm

WWDiesel wrote:

Mountainman wrote:

Oh, I do have a suncoast, but I'm pretty sure my problem is that my front pump is pre 2013 upgrades. I'm just going to get a new pump and install all of the transgo and sonax
Upgrades. Not doing this 4 times, 3 is enough! I thought my 2013 mopar remanufactured transmission with updated front pump would do the trick, wrong. #2 transmission also has updated front pump, but it also must have been pre 2013 upgrades as well, actually I know it was pre 2013 as I bought it around then from a lost member who didn't have the transmission worked on at all for years.

That's a real BUMMER! :banghead:

Third time's the charm! :roll:

Sounds like you may have some low line pressure issues?

Yup, I wish I was like you and had Suncoast nearby. Although I think most of the shops keep their knowledge under hat pretty tightly! I guess you can't blame them for protecting their livelihoods.

WWDiesel · **Posted:** Fri Aug 17, 2018 4:02 pm

Mountainman wrote:

Yup, I wish I was like you and had Suncoast nearby. Although I think most of the shops keep their knowledge under hat pretty tightly! I guess you can't blame them for protecting their livelihoods.

I am very lucky in the fact that I have a Super Knowledgeable transmission man in my town who is also a personal friend of mine and he has been in business for decades and don't mind sharing his knowledge or answering any questions I may have.

He is very good at what he does and I hope he stays in business for many more years to come.... :roll:

TC shudder before lockup? Slip?

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