Lurching in 4x4, Side to side Torque'n, Vibration

Silverbullet · **Posted:** Sun Nov 22, 2015 10:02 am

I bought my jeep used and think the drivetrain might have been ignored. Hoping for some help to resolve.

2WD, Runs amazing, very smooth, not one complaint, almost feels to good to be true

Part Time 4WD, @30mph on snow covered or ice road it feels great and sold

Part Time 4WD, @>30mph(went up to 70mph) (A few different issues...) on dry-ish expressway, I can really feel the 4WD, vibrations like CV joints maybe? I can also feel every little bump and the jeep "launching" or lurching over the bumps in road, TC? AND the jeep pulls side to side more noticeable than other 4WD vehicles I have driven. I felt when I came off the highway I could smell a little trans fluid. Probably should not have been doing 70mph with part time on

Full Time 4WD, Feel same as above
Low 4WD, Works Great, goes in and out fine

I have only owned manual transmission vehicles and a 2004 Grand Cherokee that was 4WD all the time and never had these issues.

Thanks all
Ben

WWDiesel · **Posted:** Sun Nov 22, 2015 11:59 am

My understanding is that you should not use Part Time 4wd on pavement, it is for off road use. It locks the front and rear axles together as one unit...
Full time 4wd is designed for use on any surface as it allows for differences in front to rear axle speeds and thus prevents bind up of the drive system... :wink:

If this is not correct, explain... :roll:

Silverbullet · **Posted:** Sun Nov 22, 2015 12:56 pm

Makes sense.... I guess? I would have figured the exact opposite of what you said. Full time means 4 equal points at full power where part time would be meant for pavement conditions

Ben

Silverbullet · **Posted:** Sun Nov 22, 2015 1:00 pm

Read some more things online, The words "part" and "full" relate to the driving conditions NOT the actual function of the vehicle. I'm such a NOOB. :lol:

So I need to go try driving it in FULL TIME now and report back. I'm sure I still have some issues to work out.

Ben

WWDiesel · **Posted:** Sun Nov 22, 2015 1:42 pm

Straight from the Owners Manual:
"Selec-Trac Operating Information/Precautions —
The Selec-Trac transfer case provides 5 mode positions - normal 2-wheel drive mode, part-time 4-wheel drive high range, full-time 4-wheel drive high range, neutral, and 4-wheel drive low range.

This transfer case is equipped with an inter-axle differential which allows driving the vehicle in the 4 FULL TIME position at all times on any given road surface including dry hard surfaced roads. The 4 FULL TIME mode allows the front and rear wheels to rotate at different speeds which eliminates driveline binding and component wear that is normally associated with driving the vehicle in the 4 PART TIME position on dry hard surfaced roads. This feature provides the safety, security, and convenience of operating in 4–wheel drive at all times regardless of road conditions.

When additional traction is required the 4 PART TIME and 4LO positions can be used to lock the front and rear driveshafts together through the transfer case inter-axle differential and force the front and rear driveshafts to rotate at the same speed. This is accomplished by simply moving the shift lever to these positions. The 4 PART TIME and 4LO positions are intended for loose, slippery road surfaces only. Driving in the 4 PART TIME and 4LO positions on dry hard surfaced roads may cause increased tire wear and damage to driveline components. "

Any questions??? :goink:

Silverbullet · **Posted:** Sun Nov 22, 2015 2:08 pm

Just did a store run and it was totally fine in FT, HOWEVERE I was having issues getting back to 2 wheel drive. I went into 2 wheel and it got stuck in Part time, had to stop, reverse, neutral, back into full back into 2 wheel before it would switch. Is there a certain sequence? Pshhh owners manual

Thank you very much for the help

http://www.jeep.com/en/4x4/faqs/

WWDiesel · **Posted:** Sun Nov 22, 2015 2:15 pm

Were you rolling or setting still? Down shifting should be performed while still slow rolling if possible to allow syncros on gears to function properly. :wink:

Silverbullet · **Posted:** Sun Nov 22, 2015 2:23 pm

Rolling, I also have tried going in and out still. doesn't seem to make a difference. The lights on dash are functioning correctly, but i can tell and feel its getting stuck in part time when it should be in 2wd (You have to go past part time to reach 2WD....) :5SHOTS:

flash7210 · **Posted:** Sun Nov 22, 2015 2:39 pm

Silverbullet wrote:

but i can tell and feel its getting stuck in part time when it should be in 2wd (You have to go past part time to reach 2WD....) :5SHOTS:

Yup. It will do that.

Whenever I go into or out of 4wd, I do it while slowly rolling in neutral.
And if it still gets stuck, I will put it in reverse for a little bit, then drive again.

WhitbyKJ · **Posted:** Mon Nov 23, 2015 5:19 pm

Yep! When in part time, on dry pavement the rear axle can actually over run the front one. There is way more play in the rear end than the front end; meaning the rear has less to push against (initally) before it takes up the slack in the bushings.. And the result is over run. When off-road or on slippery conditions it tends to just stay put.

Also, if your having 4x4 noise issues, you can find them real quick by engaging part time high and travelling slow to isolate which corner the noise is coming from.. On dry pavement

Lurching in 4x4, Side to side Torque'n, Vibration

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