Shifting out of 4WD

mtbdemon · **Joined:** Fri Aug 24, 2012 5:15 pm **Posts:** 179

I had a odd thing happen the other day going out of 4wd. When I did so, the Jeep veered to the right quite heavily. It made a bit of a whirring sound while it did this. I stopped. Shifted the transfer case in and out as well as the transmission from Drive to part to Neutral.
None of this seemed to make a difference. Once I got to a wide area I turned hard to the left and made a half circle. Only then did the transfer case shift back into 2WD. Anyone know what that was all about?

Also, is there any service I should do to the transfer case or any of the 4WD components? I'm good with my normal service, but must admit I haven't done much with this system.

Thanks,
Ken

APC9199 · **Posted:** Mon Apr 08, 2019 10:12 pm

What speed did you initially shift the 4wd at? Did the steering wheel follow the direction of travel as it veered to the right? The only thing I can think of is flex in the drive train caused by binding in the prop shaft, but that has only ever been marginally noticeable at higher speeds for me. What you experienced must have been more mechanical in nature. Have you inspected all universal joints, bushings, etc underneath the vehicle?

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

Also, is your transfer case the NP231 or NP242?

mtbdemon · **Joined:** Fri Aug 24, 2012 5:15 pm **Posts:** 179

I would guess my rate of speed was 40 MPH

I have no idea what model my transfer case is. What difference does that make and where would I find it?
Thanks for the responses!!!

Ken

iakj11 · **Posted:** Tue Apr 09, 2019 12:01 pm

casm wrote:

Also, is your transfer case the NP231 or NP242?

Didn't all the domestic CRDs get the NP242 (the one with both full time and part time 4wd)?

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

mtbdemon wrote:

I would guess my rate of speed was 40 MPH

I have no idea what model my transfer case is. What difference does that make and where would I find it?
Thanks for the responses?

Ken

Transfer case shifter patterns:

NP231: 2HI - 4HI - N - 4LO

NP242: 2HI - 4HI Part-Time - 4HI Full-Time - N - 4LO

You can also climb underneath and check the round tag on the back of the transfer case near the output to the rear driveshaft; it should be listed on there, but I've seen cases before where the tag is missing.

The reason for asking is that the NP242 has a locking centre diff, which the NP231 does not. This would affect front-wheel traction with 4WD engaged depending on whether the case is in 4HI Part-Time or 4HI Full-Time if it's an NP242.

iakj11 wrote:

Didn't all the domestic CRDs get the NP242 (the one with both full time and part time 4wd)?

I believe it was dependent on trim level, but could be wrong. Either way, best to make sure.

mtbdemon · **Joined:** Fri Aug 24, 2012 5:15 pm **Posts:** 179

Looks like I have the NP242
Are there maintenance items I should be doing? Did I try shifting back into 2WD at too high of speed? I haven't had this problem before, but I am at about 206K miles...Thank you for the help!

Ken

APC9199 · **Posted:** Wed Apr 10, 2019 12:17 pm

I think 50 is about the max speed you should be doing when shifting the 4WD, but I generally try to do it around 20.

How often and with what product do you service the differentials? The service interval is technically every 12,500 miles for the differentials, with the proper lubricant depending on your type of use. Lighter gear oils for on-road and heavier for off-road.

I still don't see how any of this can cause the Jeep to veer to one side when changing from 4WD to 2WD. I didn't see an answer to one of my previous questions...did the steering wheel pull to the right along with the vehicle when this happened?

casm · **Joined:** Sun Jan 29, 2006 5:05 pm **Posts:** 694

APC9199 wrote:

I think 50 is about the max speed you should be doing when shifting the 4WD, but I generally try to do it around 20.

The 2005 owners' manual says shifting between 2HI and either 4HI Part-Time or 4HI Full-Time has a recommended maximum speed of 55mph. This applies regardless of whether you're shifting into or out of 2HI.

In any event, there are three things to keep in mind:

Shift only with the wheels pointed straight ahead.
Do not shift if one set of wheels is spinning faster than the other (e.g., one end of the vehicle is on snow while the other end is on pavement).
After shifting, it may be necessary to lift off the accelerator momentarily in order to let the selected range fully-engage; you can usually hear a slight 'thump' in the driveline when this happens.

Quote:

How often and with what product do you service the differentials? The service interval is technically every 12,500 miles for the differentials, with the proper lubricant depending on your type of use. Lighter gear oils for on-road and heavier for off-road.

Added to this: when was the last time the transfer case fluid (ATF+4, should be replaced every 30,000 miles) checked?

Quote:

I still don't see how any of this can cause the Jeep to veer to one side when changing from 4WD to 2WD. I didn't see an answer to one of my previous questions...did the steering wheel pull to the right along with the vehicle when this happened?

Ditto, and I'm curious about this as well. I have a theory, but don't want to poison the well by mentioning it yet - more info would be good to have.

mtbdemon · **Joined:** Fri Aug 24, 2012 5:15 pm **Posts:** 179

Yes, the jeep pulled very hard to the right when I shifted from 4WD high to 2WD high.
I have never pulled maintenance on my transfer case, so I guess I better do that. Thank you for all the help and info

Ken

Shifting out of 4WD

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