My transmission shifts great, it was replaced last year under warranty with a re fabricated one by the dealer.

The Oem Euro Torque converter that was installed with the swap was problematic from the beginning though.

It shuddered especially with the GDE hot Tune.

Yesterday, I changed my front and Rear differential oil because it was due.

I decided to go with Lucas SAE 75W-90 Synthetic Gear Oil for the rear: http://lucasoil.com/products/gear-oil/s ... c-gear-oil

and

Lucas Heavy Duty 80W-90 Gear Oil for the front: http://lucasoil.com/products/gear-oil/g ... 0-gear-oil

And the most beautiful thing happened, the shudder has been reduced to nil and the drive line noise is gone.

If you are experiencing shudder and drive line noise, I would highly suggest doing what I did. You may not have to use the Lucas gear oil but synthetic oil in the rear, the conventional oil I used previously didn't produce the same result.

Make sure to clean out the bottom of the rear diff.

Reach in there and get the dirty mud out that has accumulated at the bottom before you close it up. You can feel the soft mud if you reach in and push down with your finger.

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2006 Liberty Limited CRD, Deep Beryl Green, Yeti tune, Arp studs, new cams, rockers, lifters, TB. "Green Monster"
2005 Liberty Sport CRD, Deep Beryl Green, GDE Hot Tune, ARP studs. "Rocket"
1982 Fiat 124 Spider Convertible. "Fiona"

Congrats on the find! Do you suspect the condition of the diff (with all that debris), the weight of the oil, or the fact that it's synthetic? I've used several types of quality oils of a few different weights, both synthetic and conventional (all within the range the manual states) and never had any issues other than slight changes in feel/smoothness. Wondering (out loud) if the selection you made in this case (lucas synthetic) was just a red herring or if you found the holy grail of driveline vibration

Dan

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2005 Silver CRD Limited
245/75R16 GoodYear Duratracs
Fumoto drain | ProVent CCV Filter
Stanadyne FM100 filter | Cummins fuel pump
GDE Eco | SEGR | BoulderBars | FrankenLift | Frankenskids

Dan,

I don't know about that, I just know that what was present before is not present now.

Drive line noise is definitely eliminated.

The shudder was felt at speed above 65 mph and now it is non existent.

I am sure though that if I were to tow additional weight, I would experience shudder again.

With the setup that I have now, I can say that my shudder has been reduced if not all gone and so is the drive line noise.

_________________
2006 Liberty Limited CRD, Deep Beryl Green, Yeti tune, Arp studs, new cams, rockers, lifters, TB. "Green Monster"
2005 Liberty Sport CRD, Deep Beryl Green, GDE Hot Tune, ARP studs. "Rocket"
1982 Fiat 124 Spider Convertible. "Fiona"

Maybe it was not shudder, before I had the Euro TC, shudder was never a problem at high speed, more at low speed when the engine was grunting.

I only experienced under lower speed loads?

I am not quite sure about the correlation between transmission shudder and diff fluid, does not make sense to me?

_________________
2006 LTD Bright Silver loaded with all the needed mods, CCV intact.
Proudly supporting CRD vendors, and their development of quality parts and accessories.
Equipped with HDS thermostat, plenty of heat, faster warm-ups, increased fuel mileage.

It did happen and it still does happen in lower speeds, especially when the transmission shifts up at a point in time when I floor it to pass a slow moving vehicle for instance or floor it while going up a hill.

It is lessened and I am sure that if I tow the trailer, I will feel the shudder but I don't plan to take the trailer out anytime soon just to test this..

I do not know the reason behind it and possibly a transmission/drivetrain engineer may know or someone else may want to chime in.

It may also be due to the removal and clean out of all the thick grey mud that was stuck at the bottom of the differential

I do not know why but it is almost non existent now.

_________________
2006 Liberty Limited CRD, Deep Beryl Green, Yeti tune, Arp studs, new cams, rockers, lifters, TB. "Green Monster"
2005 Liberty Sport CRD, Deep Beryl Green, GDE Hot Tune, ARP studs. "Rocket"
1982 Fiat 124 Spider Convertible. "Fiona"

So it did not eliminate shudder, cause it would have been a miracle if it did?

_________________
2006 LTD Bright Silver loaded with all the needed mods, CCV intact.
Proudly supporting CRD vendors, and their development of quality parts and accessories.
Equipped with HDS thermostat, plenty of heat, faster warm-ups, increased fuel mileage.