Delay in engaging/disengaging 4WD

asonyi · **Posted:** Sat Nov 15, 2014 3:52 pm

I noticed the other day that when I changed the shifter in my Jeep into Part Time 4WD, there seemed to be a delay (several minutes 5-10) before it engaged and the same for when I changed the shifter back to 2WD to disengage it. Is this normal? Does it only engage the system when it senses some slip while in Part Time 4WD, maybe same for Full Time 4WD?

Also, on a previous thread posted a while back, today I replaced both front CV half shafts due to many responses suggesting this could be the issue. It was due to hearing clunking noises while making full turns at slow speeds and also going over some bumps. Well, turns out it's not the CV joints, because I still hear the same noise as before. Last resort is to go to the dealer to have them check whatever else out, and if they can't diagnose the issue, then I think I'm forced to sell the darn thing and be rid of it and future headaches. I've also had this issue checked with 3 other mechanics with no luck. I love the Jeep CRD but can't have this continued problems and wasting money.

flash7210 · **Posted:** Sat Nov 15, 2014 7:11 pm

4wd:
Yes that's normal.
Everything in the transfer case has to be perfectly aligned to achieve true 4wd function. Both when engaging and disengaging.

Clunks:
Suspension parts wear out and you start getting these noises. I would check your front lower ball joints first. These are known to wear out prematurely.

asonyi · **Posted:** Sat Nov 15, 2014 7:21 pm

Thanks for previous info.

Looked at the front lower ball joints and those were fine.

Army Ranger · **Posted:** Sun Nov 16, 2014 12:55 am

Check your front driveshaft CV joints. The rear one (transfer case end)has been my problem for the last few months. Make sure the boot isn't torn and absolutely no slop in the joint.

flash7210 · **Posted:** Sun Nov 16, 2014 8:26 am

^^^
That's a possibility too.
Mine made a jingling sound before I replaced it.
But I could only hear it with the windows rolled down.

You will also want to check your shocks, shock mounts and spring isolators.

asonyi · **Posted:** Mon Nov 17, 2014 9:03 am

Just replaced the CV joints including the half shaft assembly on Saturday. My suspicions are leading to something shock related. This thing is like a ghost.

DOC4444 · **Posted:** Mon Nov 17, 2014 10:33 pm

Maybe there is a misunderstanding, but the transfer case should change from 2WD to 4WD when you move the lever, no delay. Getting into low range sometimes requires alignment of the universe.

DOC

asonyi · **Posted:** Tue Nov 18, 2014 9:43 am

There is definitely a noticeable delay when changing the lever from 2WD to 4WD Part Time. I think also same happens when going from 2WD to 4WD Full Time. What might cause this?

Rich · **Posted:** Tue Nov 18, 2014 9:48 am

what sequence are you running when shifting between 2wd and 4wd?

asonyi · **Posted:** Tue Nov 18, 2014 9:50 am

Just driving along, maybe 25-30 mph and just change the lever from 2WD to 4WD Part Time or Full Time, depending on my preference.

Rich · **Posted:** Tue Nov 18, 2014 11:25 am

Shifting from 2wd to 4wd;
Slow to 5-15, off throttle, shift to Neutral, pull lever to 4PT/4FT, shift to Drive, continue on your way.

Shifting from 4wd to 2wd;
Slow to 5-15, off throttle, shift to Neutral, push lever to 2wd, shift to Drive, continue on your way.

Shifting between 4PT and 4FT can be done on the fly, but do so off throttle.

There should be no torque load on the drive-train when shifting the t-case.

papaindigo · **Posted:** Tue Nov 18, 2014 1:50 pm

For what it's worth asonyi has the Selec-Trac system (Command-Trac has no 4-wheel full time mode; labeled as 4-wheel is part time - seems strange) and according to the OEM tag that came on my CRD with Selec-Trac shift instructions are as follows:
1. 2-wheel to either 4 part or full time - do a firm continuous pull on the lever at any speed under 55mph; momentarily release go pedal once or twice AFTER the shift (up or down) to improve engagement/disengagement time (this could be your issue) - if you do the shift at a stop you may have shift the tranny from Drive to Reverse back to Drive for the system to be "happy" = delayed shifting out of 4 part time can be uneven tire wear/size/pressure or heavy vehicle load.
2. shift into 4-wheel low - slow to 2-3 mph; shift tranny into neutral and while still rolling firmly shift into 4 Low WITHOUT a pause in transfer case Neutral; and then put tranny back in gear. Might hear some unhappy noise while shifting which is normal and speed in 4-low must be kept under 25mph.
In any case don't wait until you are stuck to shift a Selec-Trac system as this system is set-up to only shift properly if all 4 wheels are rotating at essentially the same speed otherwise transfer case damage may occur. See Owner's Manual for a few other comments about getting into and out of 4-Low.

Hexus · **Posted:** Tue Nov 18, 2014 2:59 pm

I have an '06 CRD Limited. I've never had ANY issue shifting into 4 High, 4 Lo, or Part Time 4 Wheel Drive in mine, and it has ALWAYS been immediate.

joelukex4 · **Joined:** Thu Sep 29, 2011 4:54 pm **Posts:** 386

papaindigo wrote:

For what it's worth asonyi has the Selec-Trac system (Command-Trac has no 4-wheel part time mode) and according to the OEM tag that came on my CRD with Selec-Trac shift instructions are as follows:

No to be picky but Command-Trac is ONLY 4-wheel part time mode. It has no full time feature.

papaindigo · **Posted:** Tue Nov 18, 2014 4:05 pm

joelukex4 is correct although it's sure not obvious from the manuals which just say Command-Trac has 4-wheel drive and makes no mention of part time or full time. However if you look at other places the manuals say that Command-Trac 4-wheel drive locks things together and should not be used on dry pavement which is what Select-Trac part time 4-wheel does. I've corrected my note.

Personally I've given up on figuring out the weird differences and just use 2 wheel, 4-wheel full time if 4-wheel is needed, and once 4-wheel low to pull an idiot in a street sedan out of Florida beach sugar sand.

joelukex4 · **Joined:** Thu Sep 29, 2011 4:54 pm **Posts:** 386

The whole concept is backasswards but does make some sense if you think about it this way: full time 4WD can be used all the time and Part time 4WD should only be used part of the time depending on road conditions although I have used my 4WD part time in my Cherokee many a time on partially dry pavement with no issue. Up north conditions are such that roads see many different amounts of ice and residual snow from plowing. If you are going straight on a highway or interstate differentiation between the front & rear tires are nil because the arc they are traveling is the same and the driveline will not bind up. There is no issue using part time 4WD if you are only going straight.

My brother has a CRD and I had to school him that he should use full time 4WD for all winter road driving. Part time was for off road mainly. Confused by the manual I guess.

Why did the engineers design the Select-Trac to go into part time first. It should have been done the other way with full time 4WD engaged at the first position then locking the center diff in the transfer case at the second position to get part time 4WD.

flash7210 · **Posted:** Tue Nov 18, 2014 5:47 pm

I've never had a problem getting into 4wd, in either mode.
It getting back into 2wd where it gets stuck in PT 4wd.
The only difference between FT and PT 4wd is that in PT the front and rear driveshafts are fully locked together. When driving straight, you can't tell the difference. But when making a sharp turn you will know immediately when you are stuck in PT 4wd.

FT 4wd is like AWD and the vehicle behaves like a AWD car.
PT 4wd is like 4wd and behaves like a 4wd truck will fully locked hubs.

ATXKJ · **Posted:** Wed Nov 19, 2014 1:24 am

The Part Time - Full time is confusing if you think of it as a description of the transfer case function - it is not.

Part time- Full time is an instruction on how to drive.

you can use Full-time - Full time - dry weather - paved roads ect.

you can only use Part-time - part of the time - slick roads - off road ect.

if you think of it as a driving instruction - it makes sense.

(and when I had mis-matched tires - full time still worked - part time did not - and reverse was the only way to insure it disengaged)

asonyi · **Posted:** Wed Nov 19, 2014 8:51 am

Did a final test run yesterday. So engaging it into either 4WD part time or full time was no problem. Didn't really notice a difference when driving straight or hear a difference in engine noise or anything. Only noticed it when making sharper turns. I noticed resistance in the steering. Only noticed delays on some occasions disengaging 4WD to 2WD but only for a few minutes.

Totally agree that the explanation of the Selec-Trac system is quirky. The way it is labeled/defined is the opposite of its function. The first time I read the manual regarding the 4WD system, I actually had to read it over a few more times because it didn't make sense at first.

Delay in engaging/disengaging 4WD

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