suncoast installed but shuder still there... not good.

clday25 · **Posted:** Thu May 28, 2009 4:42 pm

gmctd wrote:

...mine's jacked a little with larger tires, which I've reset the ratios so as not to upset the ABS, TCM, and ECM

Please explain what you mean by "reset the ratio" :?:

gmctd · **Posted:** Thu May 28, 2009 10:05 pm

Reset the tire size\rolling diameter parameters to true up the VSS input - has nothing to do with the shudder, just makes the speedo indication reliable

gmctd · **Posted:** Fri May 29, 2009 1:25 pm

You'll need to see Mr Moservice for an audition with Starscan (or DRBIII)...................

clday25 · **Posted:** Fri May 29, 2009 1:29 pm

gmctd wrote:

Reset the tire size\rolling diameter parameters to true up the VSS input - has nothing to do with the shudder, just makes the speedo indication reliable

Wasn't think'en about the shudder..... which i hardly get at low RPM's climbing hills in O/D with healthy amounts of skinny peddle applied...

So how do you go about reseting the VSS input? Stealership visit? I wasn't aware we could do this.... currently run'en 265/75's and ya, speedo is slow.

blue94yj · **Joined:** Wed Jun 27, 2007 7:52 am **Posts:** 20

Bringing this back to the top. I just installed Suncoast and inmotion I now have a shudder at just above 60 if I try to accelerate quickly. Never had a shudder with everything stock.

I just installed the inmotion ecm this morning so I'm hoping maybe it is still learning and adjusting, but if not who has been running the friction modifier the longest and has there been any ill effects?

Charlie

DOC4444 · **Posted:** Wed Jun 10, 2009 9:19 pm

Blue,

As GMCTD has been saying lately, with added torque, a Suncoast TC may not be the answer to the shudder problem. Our '05 is fine (non-towing) with stock ECM installed. InMotion ECM triggers the shudder, even when not towing. Two tubes of "Dr. Tranny" altered the frequency of the shudder, but didn't stop it.

So, if you want to put take avantage of extra power, we have to wait for the smarter folks on this site to figure out what the real fix is.

DOC

rubicon03 · **Joined:** Sun Jan 06, 2008 1:52 pm **Posts:** 28

To all who have experienced the "shudder":
I too have felt the same condition with both of the crd's which I have had for 4 years each now, bought both new and felt shudder before 10,000 on both.From what I have discovered it does seem to be an issue related to vibration that sets up under more extreme low engine rpm/ high torque conditions in lock-up in fourth and/or fifth gear. I installed the SEGR's on both crd's which allowed me to crank up the power with a TDC box with no CEL.The vibration at 57 in lock-up when you hit a hill was even more apparent,but is only in about a 2-3 mph window
However bad the Shudder is though ,I found that if i was driving with the transfer case set to Full Time Four wheel the shudder condition goes away completely,on BOTH of my jeeps.But obviously most of us will not run in this setting year round . So I can only assume that by sending some of the torque to the front axles cancels out the engine torque pulsations due to the second drive shaft directional rotation load.
If you look at the tail mounting rubber that supports the tranfer case tail you will see that it is EXTREMELY soft and bouncy.I rigged up a temporary clamp on the rear tail mount to reduce the amount of bounce that could develope in the mount and surprisingly enough the shudder was gone in the 2wd setting: but it also caused more engine hum to transmit into the cab at the floor because it must be too rigid. There seems to be a small rpm window combined with higher torque that causes a pulsation to set up in the drive train. Once the rpm and mph increase past this window( about 1700 rpm on mine) the shudder dissipates.
If this shudder was related to the torque converter the shudder should be present in 2 OR 4 wheel drive.
This is also a condition I experienced in the early and mid 90's on the 3/4 and 1 ton Rams with a Cummins 6 diesel.At low engine rpm and in high gear if you crowded the accelerator down without down shifting it could develope a violent shudder shake condition,so far that it could damage the drive shaft .
The shudder of our jeep doesn't even come close to this.Maybe some one can develope a better tranfer case tail mount???
Try putting yours in Full time long enough to see if the shudder condition disappears.
This is just my 2 cents worth but I think the mount is where our problem lies,and the F37 was an attemp to reduce the power enough to make it go away------maybe on some!
I will not give up my crd's power!!

rubicon03

DOC4444 · **Posted:** Wed Jun 10, 2009 11:46 pm

Rubicon,

Thanks so much for that insight. Any idea what plane the excessive movement may be in based on how you clamped the mount?

I'm inclined to add some form of damper rather replacing themount with something firmer.

Thanks again,

DOC

blue94yj · **Joined:** Wed Jun 27, 2007 7:52 am **Posts:** 20

That actually makes alot more since to me because I feel the shutter right between the seat it seems like. I will give the full time a try tomorrow because I can cause the shutter on demand now.

I haven't looked at the mount but if this is the problem it seems like it shouldn't be to hard to firm it up a little the trick might just keeping from making it to firm.

Thanks,

Charlie

gmctd · **Posted:** Thu Jun 11, 2009 1:49 am

That's good input, Rubi, veddy intedesting - DCJ has been using those Mitsubishi-derived saddle mounts since back in the '80's when they co-partnered with MHI for the Starion and other Mitsu rwd and fwd vehicles, dumping the old VW-based Omni, Horizon, and etc fwd platforms - the mounts worked wonders for all the 4cyl gasser(patooie!) stuff in the rwd unibodies, eliminating harmonics from those anemic examples into the floorpan - Diesel's are a different breed completely, tho, requiring a separate frame with rubber body mounts, like in the RAM trucks - even the dual balance shafts, used successfully in the 2.6L turbo-charged 4cyl in the Starion, cannot eliminate the power-stroke pulses in a relatively large displacement 4cyl turboDiesel - operational vibration is the main reason why most passenger vehicle Diesel engines are less than 2 Liter - for a real breath-shaking experience, take a ride in a BT3.9L Cummins-powered vehicle, only 1100cc's larger than our 2.8L - those saw service in the bread-truck\equiv step-vans, where it was nigh-on to impossible to see anything in the rear-view mirrors anywhere near idle - that same mount in HD form sits under the 48RE behind the 5.9L Cummins and, even heavier duty, that King Kong version of the 545RFE, the 68RFE behind the 6.6L Cummins - the big sixes are much smoother than a 4cyl, even a dual-balance-shafted 4cyl, but can still clean the plaque off yer teeth when excited -
I say get used to it, wear it proudly, like a unique badge - it makes the very noticeable statement that you are riding in a vehicle equipped with a powerful turboDiesel engine, even if DCJ did try to F37 the stinky little mule into the insipid, non-exciting soccer-mom class

rubicon03 · **Joined:** Sun Jan 06, 2008 1:52 pm **Posts:** 28

I think that a short rubber mounted vertical link from the cross member up to the transfer case on the far left side (drivers side)as a strut would stop the oscillations, something similar to a suspension stabilizer bar link on the front of a car or 2wd truck for example. I do not believe it is a totally destructive force but could eventually cause an issue in the rubber element detaching on the mount itself .After all this shudder is not a condition one feels all the time during normal operation.The mount is a "trapped" assembly so it will not allow the tail to become separated .
I would not change the original tranfer case mounting point ,just add the vertical stiff leg to stop excessive travel.There is however down side to adding hardware up here in the tundra climate;the more attached the engine is to the vehicle frame, the more engine vibration noise that seeps through into the cabin at -25*F from stiff rubber mounts.

rubicon03

DOC4444 · **Posted:** Thu Jun 11, 2009 8:31 am

Rubicon,

Thanks again. So you think the excessive movement is mostly in the vertical plane. I just crawled under the Jeep for a quick look before my wife headed off to work. It was a little difficult to see because of the skid plate under the transfer case, but it looks like a huge portion of the transfer case (outboard side) is essentially unsupported by anything. I can see how this long, heavy lever arm could likely cause excessive rotation of the case on its mounts.

The ideal place to restrain the movement would seem to be on the extreme outboard end, but that seems to be over the skid plate rather than the crossmember. However, maybe something mounted in the corner formed by the frame rail and skid plate would be strong enough.

Anyone able to take photos with the skid plate off so we can start to come up with a plan for a specific "steady" bar/bracket arrangement? (I won't have access to the Jeep to do that until the weekend.)

This appears to be a potential breakthrough for a sticky, longstanding problem and is greatly appreciated.

DOC

gmctd · **Posted:** Thu Jun 11, 2009 10:18 am

I have been assuming, based on reporting styles, that possibly we're dealing with maybe two separate problems: Diesel power-stroke reaction and possible EMCC response to TCM management - in the first case, I think you're gonna be spitting into the wind with anything you try - southern (to you) models do it in summer temps, just slightly warmer than -25* - if it could have been solved by altering the isolator stiffness in any plane, DCJ would have re-spec'ed the compound, and your increased vibration at low-temp rubber stiffness confirms that - the fact that they F37'ed it is significant in that aspect: reduce power, reduce vibration - don't forget, the transmission mounting xmember is attached directly to the floorpan: any excitement\commotion will be transmitted into and amplified by that huge piece of tin - the harmonic balancer inertial mass flywheel on the drive shaft is there to remove a major portion of the 4cyl forces transmitted into the rwd drivetrain which is all attached to the floorpan in these uni-body platforms - the exhaust gets a flexible vibration isolator in the downpipe, where the exhaust hangers are attached to the....you guessed it: floorpan - even the engine cradle is directly attached to extension rails from the floorpan - could have helped had that cradle been isolated with rubber body-mounts, ala the Camaro\Firebird platforms, even with the KJ's as-equipped liquid-filled damper\isolator motor mounts - maybe mine does it too - maybe I just don't notice it, being accustomed to (and reveling in) vibrations from a Diesel engine that makes huge low-rpm torque based on the small bore\long crank-arm configuration, a concept that gassers (patooie!) are simply unable to take advantage of - tho possibly the current direct-injected versions, pioneered by MHI back in the '80's-'90's, and a few modern models of which are running the streets today, will have the same problems with the 4cyl rwd models, which are scarce as hen's teeth

FYI, that's the current technology, Doc: the unsupported mass of the xfer case, hanging abaft the transmission mounts, serves to dampen driveline vibration in several planes, as does the flywheel on the rear driveshaft

rubicon03 · **Joined:** Sun Jan 06, 2008 1:52 pm **Posts:** 28

I'm with gmctd .Myself I probably will not do anything to alter the mounting or adding a strut at this point unless I have more time to play with it.Once the EGR's were out of my life all problems went away.The shudder is really more of an occasional irritation than a full blown problem for me.
For those who are pursueing the "fix" it may be easier to attach to the front or forward side of the transfer case with a damper to the crossmember to the far left..I know,easier said than done but not impossible.

rubicon03

suncoast installed but shuder still there... not good.

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