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response from Jeep Engineers about front diff breaking
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Author:  jg45 [ Wed Apr 18, 2007 6:27 pm ]
Post subject:  response from Jeep Engineers about front diff breaking
I logged on to the jeepforum.com site to attend this forum meeting with Jeep engineers this afternoon and asked the below questions about the weak front diff. They didn't really give a useful response, but here is what they said:


Quote:
Originally Posted by jg45
Good afternoon,
I have a 2003 Jeep Liberty KJ 4WD. The front end is the same as the 2007 I believe. Several people have had issues with the front diff housing breaking. It appears that the breaks occur when the front wheels are spinning and then grab tracction quickly. Has DCX done anything to fix this issue or are there any plans to? If not, can you as engineers propose a solution we the owners could do to strengthen the housings. A common suggestion is to put a steel collar around the neck of the housing around the area where the pinion bearing resides. Does this sound like it would work? Thank you again for taking time to speak with the Jeep community.


I have seen the issue you describe on the Liberty front axle. We are always looking at how our customers are utilizing our vehicles and re-evaluating how we test and validate their designs to try to meet their needs, and making changes based on those evaluations. I'm also familiar with the collar you describe, but I cannot speak to whether it will actually help or not.
Author:  Tokyojoe [ Wed Apr 18, 2007 6:46 pm ]
Post subject: 
A company answer
Author:  jerbacher [ Wed Apr 18, 2007 6:47 pm ]
Post subject: 
I'm sure they have to be pretty careful about what they say to protect the company.
Author:  Jeep4me99 [ Wed Apr 18, 2007 7:00 pm ]
Post subject: 
hmmmm...no way would they give you a real answer at an online discussion...def corporate answer

anything else helpful or worthwhile come out of that deal???i was busy at work so I couldnt get in on it.
Author:  BVCRD [ Wed Apr 18, 2007 7:16 pm ]
Post subject: 
Jeep4me99 wrote:
hmmmm...no way would they give you a real answer at an online discussion...def corporate answer

anything else helpful or worthwhile come out of that deal???i was busy at work so I couldnt get in on it.



He says TC for the F37 are different than OEM. More "robust."
Author:  jg45 [ Wed Apr 18, 2007 9:34 pm ]
Post subject: 
Below are things I found interesting:

"The KJ is Trail Rated and has gone on many real world off road development / validation trips (Moab, Colorado, Paragon, Attica, Silver Lake Sand Dunes, Kentucky, etc.) in addition to our Proving Grounds events. We strive to maintain the Jeepness in our vehicles and will contine to do so."


The new Liberty is going to have a 5 link rear suspension instead of the tri link currently.

There was a brief discussion of the electronic throttle control with a manual transmission. They basically said to get used to it.

ESP is calibrated to allow for some differential in tire size to allow for tire replacement.

CRDs only came with 16 inch tires for fuel economy reasons.

May need to recalibrate the speedo for ESP to work correctly with larger tires.


The Select-Trac II is an On Demand case that uses clutch packs to transfer torque to the front axle. The amount depends on a variety of input parameters. It works in conjunction with the ESP traction control system which transfers torque from side to side across an axle based on wheel speed differences. In 4Lo, it effectively locks the f/r props together. This case has 2wd/4 On Demand / Neutral / 4Lo.
Author:  Guest [ Wed Apr 18, 2007 9:52 pm ]
Post subject: 
jg45 wrote:
Below are things I found interesting:

"The KJ is Trail Rated and has gone on many real world off road development / validation trips (Moab, Colorado, Paragon, Attica, Silver Lake Sand Dunes, Kentucky, etc.) in addition to our Proving Grounds events. We strive to maintain the Jeepness in our vehicles and will contine to do so."


So... how'd the Compass fare at Moab?!? :twisted:
Author:  QuestMan [ Wed Apr 18, 2007 10:02 pm ]
Post subject: 
Quote:
"The KJ is Trail Rated and has gone on many real world off road development / validation trips (Moab, Colorado, Paragon, Attica, Silver Lake Sand Dunes, Kentucky, etc.) in addition to our Proving Grounds events. We strive to maintain the Jeepness in our vehicles and will contine to do so."


I live about 2 hours from Silver Lake. No offense, but as long as you keep the tires at 10 psi, even a COMPASS can make it out there. :P
Author:  PBrug [ Wed Apr 18, 2007 10:38 pm ]
Post subject:  Re: response from Jeep Engineers about front diff breaking
"We are always looking at how our customers are utilizing our vehicles and re-evaluating how we test and validate their designs to try to meet their needs,"

To me he is saying:

"We know 95% of the KJ's we sell will never be used off road, let alone pushed to the point in which the front diff will break. So we built it as cheaply as we could so that it was fully functional for how most KJ's will be used, on the road."
Author:  swyszomirski [ Wed Apr 18, 2007 11:22 pm ]
Post subject: 
Quote:
"We know 95% of the KJ's we sell will never be used off road, let alone pushed to the point in which the front diff will break. So we built it as cheaply as we could so that it was fully functional for how most KJ's will be used, on the road."


Now that seems to be a very accurate translation... :evil:
Author:  Pablo [ Thu Apr 19, 2007 1:44 am ]
Post subject:  Select-Trac II
jg45 wrote:
Below are things I found interesting:

The Select-Trac II is an On Demand case that uses clutch packs to transfer torque to the front axle. The amount depends on a variety of input parameters. It works in conjunction with the ESP traction control system which transfers torque from side to side across an axle based on wheel speed differences. In 4Lo, it effectively locks the f/r props together. This case has 2wd/4 On Demand / Neutral / 4Lo.


Am I reading this right? On-Demand? They replaced 4-Full time and 4-Part time in select-trac with on-demand? Uggg.. like a CRV with 4Lo. You have to be kidding me. :evil: :evil: :evil:

Clutch Packs? So it is like a LSD that goes out when the clutches get old (at 30,000 miles)?

So how does 4-FULL time work in a real Select-Trac? I have never really looked into it... I just know it was chain driven and was under the assumption it is basically a differential but between front and rear wheels instead of left/right wheels.

I just get the feeling this is another cost saving parts downgrade disguised by marketing literature as something good. :evil:
Author:  Blue KJ in PA [ Thu Apr 19, 2007 6:59 am ]
Post subject: 
Yep it's the new version of the "Trail-Rated" marketing scam...oops plan.... :roll:
Author:  Jeepjeepster [ Thu Apr 19, 2007 7:31 am ]
Post subject: 
Ive always thought the select-trac needed some clutches. Hopefully it will work out better than the current select-trac.

The NV-245 in the WK's seems to do great.
Author:  Maximum Carnage [ Thu Apr 19, 2007 9:01 am ]
Post subject:  Re: response from Jeep Engineers about front diff breaking
jg45 wrote:
A common suggestion is to put a steel collar around the neck of the housing around the area where the pinion bearing resides.


I missed the group buy that was done on this. But who made them and do they actully work/help?
Author:  dirtykj [ Thu Apr 19, 2007 10:40 am ]
Post subject: 
Tokyojoe wrote:
A company answer


I think you mean a CYA answer ...
Author:  Jeger [ Thu Apr 19, 2007 11:11 am ]
Post subject: 
Jeepjeepster wrote:
Ive always thought the select-trac needed some clutches. Hopefully it will work out better than the current select-trac.

The NV-245 in the WK's seems to do great.


If it has clutches AND a locking center diff that might be fine. As long as when the clutches wear out you still have a regular "open" transfercase...like when a trac-lock rear diff wears out you still have an open diff, it wouldnt bother me at all. Now if the cluthes are the only thing sending power to the front, and when they wear out you have no 4WD that would suck.
Author:  Pablo [ Thu Apr 19, 2007 8:22 pm ]
Post subject: 
Jeger wrote:
Jeepjeepster wrote:
Ive always thought the select-trac needed some clutches. Hopefully it will work out better than the current select-trac.

The NV-245 in the WK's seems to do great.


If it has clutches AND a locking center diff that might be fine. As long as when the clutches wear out you still have a regular "open" transfercase...like when a trac-lock rear diff wears out you still have an open diff, it wouldnt bother me at all. Now if the cluthes are the only thing sending power to the front, and when they wear out you have no 4WD that would suck.


That is pretty much what it sounds like--they wear out and then you have 2wd. I am also worried about the "On-Demand" aspect of the system. I don't know about Select-Trac II, but with the Toyota and Honda "On Demand" systems, it means you have NO 4wd until a wheel starts to slip and then the computer decides to send some power to the front wheels. Well by that time it is likely too late as you are loosing forward momentum while it thinks about how much power to send where. The regular select trac and range rover systems power ALL 4 wheels ALL the time when in 4-FULL-- they are just not locked 50/50 front to rear like part time is. (Part time is also available in Select Trac).
Author:  jerbacher [ Thu Apr 19, 2007 8:26 pm ]
Post subject: 
it seems to me that the selec-trac system in the KJs works really really well. why mess with a good thing? if they wanted to make it electronic, then fine. and if they wanted the 4wd to be easy enough for a caveman to operate, then just take out the 2wd option and leave the full-time system how it was! nothing wrong with running the selec-trac full time all the time (hence FULL TIME)
Author:  Guest [ Thu Apr 19, 2007 11:55 pm ]
Post subject: 
I wonder what the replacement for the TJ will look like :roll:
Does anyone wonder why Toyota sales are skyrocketing?
Author:  wendell [ Fri Apr 20, 2007 7:15 pm ]
Post subject: 
The only problem with the electronic t-case is, the shift motors wear out, a manual lever doesn't and it isn't very manley. My ranger has the electronic t-case and it workd really well, very smooth and quick, but I still wish it had a lever, it just doesn't seem right.
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