Suncoast TC with InMotion Stage II

DOC4444 · **Posted:** Sat Feb 28, 2009 8:33 pm

I seem to recall someone complaining a while ago about still experiencing the dreaded 55 MPH "shudder" (lock-up clutch can't handle the torque) after installing a Suncoast TC when using an InMotion Stage II ECM.

We have a stock TC and trans. With the OEM ECM installed, there is no shudder at 55 without a trailer, but there is a rather violent shudder with the IM ECU, even with just a load of one person. (I try to "drive around the problem" to minimize damage.) For the same reason, we have held off towing very much.

In any case, could as many people as possible weigh in as to whether you do, or do not, experience the "shudder", even WITH the Suncoast TC, when using either an IM ECM or a tuner that adds significant torque?

Thanks as Always,

DOC

warp2diesel · **Posted:** Sat Feb 28, 2009 8:36 pm

....will solve the problem with trailer towing. When I do mine, guess what, it will get the resistor with a bypass switch. Up for tow down for street.

GMCTD has covered this one, check in his haystack in the tech section for other valuable info.

CATCRD · **Posted:** Sat Feb 28, 2009 8:53 pm

I have both and don't have any shudder.

DOC4444 · **Posted:** Sat Feb 28, 2009 9:08 pm

It's my understanding that the resistor in the TransGo kit firms up the intermediate gearshifts. I did not think it affected TC lockup performance. I'd appreciate it if GMCTD could comment as to whether it also firms up the engagement of the TC lockup clutch. If so, it might be a worthwhile mod, even without addng the Suncoast TC.

Thanks as Always,

DOC

CRDMiller · **Posted:** Sat Feb 28, 2009 9:55 pm

It learns and adapts to the resister via the "slow learn" process built into the tcm/pcm. After a while the resister is useless. This is not my first hand experience, this is a recall of other posts I have read.

That said, I had significant shudder when I got my IM II, it was reduced significantly after I replaced my slip yoke/dual mass flywheel/harmonic balancer, u joints and had the drive shaft balanced.

Others have reported reduction of shudder at high tq low rpm by replacing u joints. No one has reported it cured by adding the tc. (afaik)

Now, i just got a Frankie II premium and my shudder is nearly non existant.

BUT it is time to replace my air filter so we'll find out :P I was going to report this in the shudder thread, after i was positive. (oddly enough it was my wife who noticed first) it used to knock your teeth out, you know? :P

pismo61 · **Posted:** Sat Feb 28, 2009 9:59 pm

Stock I had no shutter. With the IM. Tune I have the shutter.I can easily drive around it.Its 4th gear at 55 and 5th at 65 or so.

gmctd · **Posted:** Sat Feb 28, 2009 10:07 pm

The resistor informs TCM that line pressure is low, to which TCM responds by pulsing pressure up to expected levels - increased line pressure effects everything in the hydraulic loop, from servos to clutches to pistons, incl the TCC apply piston - the Suncoast Hemi TCC is much improved over oem KJ version, so should never slip under any torque application - I have not found it to do so with INMOTION StII, even with EDGE Trail accidentally engaged - now, there's a ride suitable fer what ails ya!

BTW, I just picked up a groggy #2 son from the clinic after getting an injection and some prescriptions for walking pneumonia, and decided to use well-established witch-doctor tactics to scare the bad debbils outta him - I think it worked, 'cuz when I finally eased up offa the go-pedal, he was fully conscious and grinnin' ear to ear...................

DOC4444 · **Posted:** Sat Feb 28, 2009 11:32 pm

Thanks GMCTD,

With that clarification, I guess I will be adding the resistor soon to see how it impacts the shudder problem before adding a Suncoast TC.

It also raises the question as to whether the owner who is still experiencing shudder with Suncoast TC and IM ECM did NOT install the resistor.

DOC

nursecosmo · **Posted:** Sun Mar 01, 2009 12:20 am

I too am planning on a resistor installation once the temp warms up past freezing. Can't wait to do some stacking a la Gmctd :wink:

.

pismo61 · **Posted:** Sun Mar 01, 2009 11:02 am

How difficult is it to install this resister?Thanx

retmil46 · **Posted:** Sun Mar 01, 2009 1:08 pm

Suncoast TC, Transgo shift kit, no resistor, new u-joints, Inmotion Stage II.

New u-joints reduced the "shudder" from the point to where it felt like going over a set of rumble strips, to where it's heard more than felt. And the intensity varies with how much throttle is applied under the conditions where it happens. Now, it just sounds like I'm lugging the engine at too low of an rpm for the amount of power it's being asked to produce.

Given that one poster said that in addition to the u-joints, replacing the harmonic balancer and balancing the driveshaft virtually eliminated the problem, reinforces my view that what we're seeing is the engine and drivetrain hitting a resonant vibration frequency under certain conditions - low engine rpm, medium to high power/torque, low gearing (4th/5th gear at low engine rpm) with TC locked up.

My theory is that it's most apparent under these conditions because with the TC locked up in 4th and 5th gears, you essentially have a solid mechanical drivetrain that is transmitting this resonant vibration from the engine throughout the entire drivetrain.

Inline 4 diesels of our size and power aren't noted for smooth running - hence the twin balance shafts down in the crankcase.

This same shudder/rumble strip effect was quite apparent with the stock tune and TC. Suncoast and tranny mods made it disappear. And it wasn't until several months after adding the Inmotion tune that it started to rear it's head again. And then a new set of u-joints quite noticeably reduced it when it did occur.

retmil46 · **Posted:** Sun Mar 01, 2009 1:15 pm

CRDMiller wrote:

Now, i just got a Frankie II premium and my shudder is nearly non existant.

Pray tell, what is this exactly?

Goglio704 · **Posted:** Sun Mar 01, 2009 1:21 pm

Lift kit from All J's...

gmctd · **Posted:** Sun Mar 01, 2009 2:23 pm

Would prolly help if the KJ had a real frame, 'stead of uni-body construction - the rear-axle upper locating bar is attached directly to the center of the rear floor-pan, such that any slight resonance is amplified into the body - additionally, driveshafts are designed and balanced to run within spec'ed angular offset - if either driveline element goes out of angle, we get vibration - or, as the combined offset angle approaches 0*, the u-joints go unloaded, such that any slight defect results in vibrational distortions transmitted into the driving and driven elements, then thru the locating arms into the frame, if it has one, which is isolated from the body - the KJ offers direct driveline to body transferral - 'nuther words, 2wd\4wd uni-bodies and Diesels don't mix well, particularly so, large displ 4cyl turboDiesels in RWD configuration - maybe that's why DCJ discontinued the series after one production run occuring over several years

B4 we start comparing the Export manual trans versions, we need to determine optional equipment installed, which adds weight resulting in lower stance, plus normal road surface conditions indigent to the several areas, US and Export, plus any Americanization of the chassis such as tire\tyre brand, type, and size, plus intake modification, plus exhaust modification, plus chassis mods such as shocks\snubbers, lifts, plus loading, plus fuel quality, in-tank fuel level during any occurance - 'nuther words, many variables create many scenarios

BTW, adding the resistor with the oem torque convertor would likely be disastrous, as that plastic stator is the reason for F37

nursecosmo · **Posted:** Sun Mar 01, 2009 9:28 pm

gmctd wrote:

BTW, adding the resistor with the oem torque convertor would likely be disastrous, as that plastic stator is the reason for F37

As far as I have been able to determine through this forum, there has only been one verifiable OEM TC which has grenaded. The plastic stator should never be an issue anyway (with appropriate cooling) seeing as how all of the shuddering occurs in lockup when the stator isn't doing anything.

gmctd · **Posted:** Sun Mar 01, 2009 10:23 pm

Do you know when the stator is doing anything?

nescosmo · **Joined:** Sat Jul 14, 2007 11:17 pm **Posts:** 202

When you install the resistor switch on the dash, do you have to take the wire coming from the botton of the tranny or there is a wire on the hornes by the engine compartment that you can use to facilitate with the wiring process.

gmctd · **Posted:** Tue Mar 03, 2009 11:43 am

http://www.lostjeeps.com/forum/phpBB3/vie ... hp?t=30576

Suncoast TC with InMotion Stage II

Who is online