Any AWD owners use Diablo tuner yet ?

[Gabe]

Wondering if any AWD owners have bought the Diablo tuner yet ... I keep hearing that the RWD cars leave rubber at the 1-2 upshift and chirp tires at the 2-3 upshift, but I'm wondering how the tuner will handle an AWD drivetrain ... will it chirp all 4 tires on the 1-2 shift ???

Anybody have any AWD / Diablo experience yet ?

[LQQKOUT]

I will let you know next week. At this time with the Superchip if I lanch to hard the front wheels will speen. When at the track after I go thrue the water box I can do a 4 wheel burnout/spin. The first time I tought something was broken because I didn't expect it.

[LouZ]

I will let you know next week. At this time with the Superchip if I lanch to hard the front wheels will speen. When at the track after I go thrue the water box I can do a 4 wheel burnout/spin. The first time I tought something was broken because I didn't expect it.

You keep slipping those front tires and something will break .....

Been there....done that

[LQQKOUT]

I am looking for stiffer rear shocks or some kind of suspension mod to stop the weight transfer to the rear.

[AWD_Guy]

Has anyone looked at the TSB for shuddering with the AWD??

It calls to pull out a single clutch disk and replace it with a modified cover that eliminates this clutch disk. My thoughts are that this clutch disk is what gives the center diff the rearward bias. Maybe chrysler started pulling this clutch disk out from the factory and is why you guys are getting the front wheel spin.

My car has the shudder on cold mornings but I haven't had the TSB done because I don't want to loose any rearward bias in the diff.

Lou, can you post up pics of your exploded diff for us to look at. We might be able to better understand how it works, and how to maybe modify it for more rearward bias.

My best guess is that the center diff is much like a rear end diff only with planetary gears, the clutch disk acts just like a posi unit would.

[done]

Has anyone looked at the TSB for shuddering with the AWD??

It calls to pull out a single clutch disk and replace it with a modified cover that eliminates this clutch disk. My thoughts are that this clutch disk is what gives the center diff the rearward bias. Maybe chrysler started pulling this clutch disk out from the factory and is why you guys are getting the front wheel spin.

My car has the shudder on cold mornings but I haven't had the TSB done because I don't want to loose any rearward bias in the diff.

Lou, can you post up pics of your exploded diff for us to look at. We might be able to better understand how it works, and how to maybe modify it for more rearward bias.

My best guess is that the center diff is much like a rear end diff only with planetary gears, the clutch disk acts just like a posi unit would.

The "disk" in question is not a clutch. It is a vibration dampener. The transfer case does not contain any clutches or viscous couplings. It contains only gears that are always meshed. The gearset is a variation of a Ravingeaux planetary set, using two sun gears and intermediate planet gears to provide the torque split. The front and rear drive shafts cannot rotate independently.

You might as well get the TSB done as the shudder only gets worse.

[AWD_Guy]

A little research later and I've found that the Ravigneaux planetary set is a pretty interesting gear arrangement. In a nutshell it's a mechanical way of varying speeds of an input and an output shaft. In our case the input and output shafts are the front and rear driveshafts. The benefit of the Ravigneaux planetary set is that you can mechanically build in bias, I also found that it is very common to build in clutches to preload the gear set to further increase a bias or even change gear ratios when the gear set is used in a transmission. It's in my opionion that the clutch that is removed does contribute to the bias, it may be that the primary function is to act as a damper although I don't really see what it would be dampening. I also agree that at single clutch disk is going to do little against hemi size torque. It would be very interesting to see how the jeep transfer is setup compared to ours.

I believe the failures we are seeing are related to the high loads these planetaries are under and the high speed they are spinning at when we start spinning the front tires. This creates heat that breaks down the fluid and walla broken gears. Of course the fix is to keep from spinning the front tires......more bias.....more traction......cooler fluid....any and all of the above?


http://www.wkjeeps.com/misc/LX/TSB/TSB_2101905a.pdf

http://www.freepatentsonline.com/200...et&stemming=on

[madeulooq]

I will have my predator tomorrow and my sidewinder should be here sometime this week too

[done]

A little research later and I've found that the Ravigneaux planetary set is a pretty interesting gear arrangement. In a nutshell it's a mechanical way of varying speeds of an input and an output shaft. In our case the input and output shafts are the front and rear driveshafts. The benefit of the Ravigneaux planetary set is that you can mechanically build in bias, I also found that it is very common to build in clutches to preload the gear set to further increase a bias or even change gear ratios when the gear set is used in a transmission. It's in my opionion that the clutch that is removed does contribute to the bias, it may be that the primary function is to act as a damper although I don't really see what it would be dampening. I also agree that at single clutch disk is going to do little against hemi size torque. It would be very interesting to see how the jeep transfer is setup compared to ours.

I believe the failures we are seeing are related to the high loads these planetaries are under and the high speed they are spinning at when we start spinning the front tires. This creates heat that breaks down the fluid and walla broken gears. Of course the fix is to keep from spinning the front tires......more bias.....more traction......cooler fluid....any and all of the above?


http://www.wkjeeps.com/misc/LX/TSB/TSB_2101905a.pdf

http://www.freepatentsonline.com/200...et&stemming=on

The function of the friction disk is stated in the repair manual as a vibration damper. It works between the input shaft and the front output shaft to keep the gearset in tension. The "shudder" fix is to remove the friction material when it gets loaded with metal flakes, thus causing the shudder.

You don't have to guess at how the transfer case is structured, just look in the service and parts manual like I did. The ravingneaux gearset has an input shaft and two output shafts.

THERE ARE NO CLUTCHES.

By the way, we only know of a single transfer case failure, LouZ's and his 392 stroker.

[LouZ]

I can not argue intelligently on this subject...

HOWEVER.... on a full power launch I feel and HEAR some type of slip...

It has been stated to me on several occasions that my front tires smoke on launch.

I have heard this "slip" every time I ran. On my 12th run I heard a BAMM right after that slip.

I have been told that there is some type of clutch built onto the planetary gear sub assembly. I was also told that system that the TBB "Fixes" is in my new t case ....and that I should leave it in.

I'll have my t case later this week after this speciality shop has finished with it.

[done]

I can not argue intelligently on this subject...

HOWEVER.... on a full power launch I feel and HEAR some type of slip...

It has been stated to me on several occasions that my front tires smoke on launch.

I have heard this "slip" every time I ran. On my 12th run I heard a BAMM right after that slip.

I have been told that there is some type of clutch built onto the planetary gear sub assembly. I was also told that system that the TBB "Fixes" is in my new t case ....and that I should leave it in.

I'll have my t case later this week after this speciality shop has finished with it.

I can feel the tires "slip" also, not much, and mostly on the 1-2 shift.

The TSB calls for the removal of the friction material from the vibration dampener. It looks kinda like a clutch, but it is a passive device.

My AWD is currently in the shop for this TSB.

As I have said before, I have spent several hours studying the service manual and the parts manual in order to understand the transfer case. I cannot understand why I am being challanged on how the transfer case works.

[lafrad]

I can feel the tires "slip" also, not much, and mostly on the 1-2 shift.

The TSB calls for the removal of the friction material from the vibration dampener. It looks kinda like a clutch, but it is a passive device.

My AWD is currently in the shop for this TSB.

As I have said before, I have spent several hours studying the service manual and the parts manual in order to understand the transfer case. I cannot understand why I am being challanged on how the transfer case works.

The only reason, is because its a tough pill to swallow... locking the front and rear axles together just doesn't match observations.

A transfer case with the front and back output shafts locked to the same RPM would have no torque split, and would NOT allow any difference in the RPM of the front axle vs the rear axle.

If you physically can't get different rpm out of the Front vs Rear output shafts, the front and back axles will never spin at different speeds, period. There is NO torque splitting if you are unable to spin the output shafts at different rpm. as soon as on axle would hang over a cliff in the air, the other axle would be sucking up ALL the torque... (100%), and if the front and rear are RPM locked, there would be no where to "split" the torque to.

If you can't get different RPM out of the front and back output shafts, turning corners would be uncomfortable and unsafe on dry pavement... 4x4 truck systems know this and have "part time" labels on them for those situations. To me, this is the convincing argument that the planetary setup allows different RPM rates for the front vs rear axles. If you wanted these two locked together, don't use a planetary setup. Use a Cheap Chain setup, or direct gear drive... both of those have the property of: both output shafts always spin at the same RPM.

By using gears in the planetary setup, there will never be any "Slip" between the front and back axles, but they will be allowed to spin at different RPM when leaving the transfer case, in a conceptually similar way that the differential spider gears work in a differential. The "input shaft" from the transmission will be spinning at, lets say, 1000 rpm, the output shafts could be spinning at 900 towards the rear, and 1100 towards the front. (this is NOT real world, as the Torque split ratio actually determines the rpm, mathematically, of the input/output shafts). If you get even more out of whack, it could get more "different", and the 1000 rpm input could be split even worse: 800 toward the rear, 1200 toward the front. The larger the difference, the more stress the planetary setup will feel (as the little "planet" gears in there are doing a lot of spinning to maintain the good torque split and RPM ratio... and they really weren't designed with a large difference in mind). If the difference becomes too great (or one axle all of a sudden finds traction), there will be HUGE stresses on that planetary setup, and it will want to go "boom". That seems similar to what happened once already.

[lafrad]

The clutch built into the setup is to absorb any "play" between the front and rear axles.... all gear sets have some play to them, and it can get uncomfortable while straight-line cruising if you are bouncing off of either side of that....

[Scott]

My car has the shudder on cold mornings but I haven't had the TSB done because I don't want to loose any rearward bias in the diff.

I was one of the first to get this TSB, that was over 30,000 miles ago. I'm very in-tune with how the AWD effects the handling under all driving conditions and I have yet to find any any reason why you would be unhappy with the result.

I still get slight oversteer when applying throttle in the snow to slide for fun. I think that implies rear-biased power distribution.

In any case, you don't really have a choice about the TSB. From every report, once the shuddering starts, it gets progressively worse. A transfer case fluid change may delay the TSB for a few thousand miles, it did for me, but that's about it.

Later, I can dig up some history on the forums or elaborate further, if your interested.

[Gabe]

Sooooo .... any AWd / Diablo experience yet ?

Anybody ?