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Author Topic: Ok to drive in 4 wheel drive without front propeller shaft ??  (Read 265 times)

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Offline patrickt

Hello All !
                 I must have been away from this great forum for maybe a couple of years now. The new format is quite a pleasant surprise !

                I have what I've determined to be an early 1950's J2 Mit-Willys jeep ( tallhood). It has a Dana front axle that appears to be (or at least looks like) a Willys MB front axle. It normally does street duty only.

                 I have yet to I.d. The transfer case, which has only one shift lever. Sorry, no pics of the transfer case / prop shaft / front axle right now. I can post some tomorrow if need be.

                 Anyway, it accidentally got shifted to 4 wheel drive on a few occasions, and is nearly impossible to shift back to 2 wheel drive on all those occasions! I understand that it could be transmission "wind up" or some wear problems.  Assuming transmission "wind up" , i will try some of the simple suggested solutions i read online.

                So on to my question. If I'm unable to shift it back to 2 wheel drive, then in the meantime " Is it ok to drive it in 4 wheel drive with the front propeller shaft disconnected ?? Anything wrong / bad with doing this ??  I'd like to minimize front tire wear and unnecessary drag on the engine, till we figure out how to get it back on 2 wheel drive. Thank You.
                    Patrick

           

Offline Bruce_W

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #1 on: March 19, 2021, 11:29:29 AM »

The “wind-up” is not in the transmission and almost not in the transfer case. Only the bottom end of the transfer case is involved.
  If you’ve got it wound up to the point that you can’t shift it out of 4WD, you probably won’t be able to remove the front driveshaft either, until you raise one wheel off the ground and allow it to “unwind”. At which point you can shift it out, and the shaft doesn’t need to come out. If you want to remove the shaft so this won’t happen again, it won’t matter whether the transfer case is in 4WD or 2WD.
  Backing up a few feet is supposed to help unwind the drive train, but I’ve not had good luck with that, even going more than a “few” feet.
BW
Until We Jeep Again...........

Offline patrickt

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #2 on: March 20, 2021, 09:44:16 AM »
     Thanks for your much appreciated reply. I am actually not a "real" 4x4 guy, rather, someone who likes old stuff. That said, I have never been on a bonafide off road course. In fact, I always thought that part time 4wheel drive should not be used in the streets only because of increased front tire wear and gas consumption. So transfer case windup is a new thing for me, but something I will definitely read more about.     

      So I wanted to ask about lifting up one wheel. So is the following procedure right ?
                                           1) With engine off and handbrake on and transmission in gear, put the front axel on something secure, just enough to let one wheel (a front wheel in this case) clear the floor.
                                          2) Put wheel chocks behind the rear wheels.
                                          3) Shift the transmission to neutral and handbrake off.
                                          4) Start the engine
                                          5) Now shift to 2 wheel drive ( and hope it does)

      Is that procedure right ? or not ? I asked because I thought it would be a sure way to loose traction, rather than going out and driving the right side wheels off the road. Thanks again.

Offline Bruce_W

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #3 on: March 20, 2021, 11:10:58 AM »
That’ll work but you’re making it harder than it needs to be.
  Park on a flat, level surface. Chock one or two wheels if it makes you feel better. Transmission in any gear or not, doesn’t matter. Parking brake off. Lift any wheel, or two if you like. As soon as it clears the floor the tension will “unwind”. It may not make a movement that you can see. Shift out of 4WD and set the jeep back down.
BW
Until We Jeep Again...........

Offline SteveKfl

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #4 on: March 20, 2021, 06:55:41 PM »
Since I only have a factory 2WD Willys, but enjoy learning about ALL Willys flat-fender models, would someone please explain what "transfer case windup" means, and "what causes it"?  Thanks. 
My Concept Roadster
62 DJ3A Dispatcher Half Top

Offline BillT

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #5 on: March 21, 2021, 09:41:14 AM »
Steve I'll give you my thoughts on the subject. Not very technical. I'm sure others will jump in with technical answers and corrections if required.

The jeeps were not designed to be operated on paved roads in 4 wheel drive. When they are driven on hard surfaces in 4 wheel drive and the vehicle goes around curves the wheels rotate at different speeds (inside wheel turns faster than outside wheel) causing binding or wind-up. On a soft surface road, dirt, the same thing happens but due to less traction the tires slip on the surface of the road (relieving tension in the drive train) and no wind-up occurs. Why it doesn't occur in 2 wheel drive I don't really know, probably something having to do with the design of the rear differential and the front axle not being engaged and the two differentials not affecting the operation of the transfer case.
'52 CJ3A, early M38A1, '70 Commando
25' travel trailer, Lance 855S truck camper
Love to camp

Offline Rus Curtis

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #6 on: March 21, 2021, 12:16:18 PM »
Good stuff on this topic!  I thought I'd add my experiences (FWIW) in hopes it'll help.

I've copied Bruce_W's comments as they were "invisible" to me until logging out.

Quote from: Bruce_W
The “wind-up” is not in the transmission and almost not in the transfer case. Only the bottom end of the transfer case is involved.
  If you’ve got it wound up to the point that you can’t shift it out of 4WD, you probably won’t be able to remove the front driveshaft either, until you raise one wheel off the ground and allow it to “unwind”. At which point you can shift it out, and the shaft doesn’t need to come out. If you want to remove the shaft so this won’t happen again, it won’t matter whether the transfer case is in 4WD or 2WD.
  Backing up a few feet is supposed to help unwind the drive train, but I’ve not had good luck with that, even going more than a “few” feet.
BW


Quote from: Bruce_W
That’ll work but you’re making it harder than it needs to be.
  Park on a flat, level surface. Chock one or two wheels if it makes you feel better. Transmission in any gear or not, doesn’t matter. Parking brake off. Lift any wheel, or two if you like. As soon as it clears the floor the tension will “unwind”. It may not make a movement that you can see. Shift out of 4WD and set the jeep back down.
BW

My experiences with "wind up" (I had always referred to it as binding but this seems more descriptive) were when I had drive flanges on the front hubs (before lock-out hubs added).  From time to time, the stick would not shift out of 4WD (mostly when hard surfaces were being crossed but occasionally on soft surfaces).  I'd simply put it in reverse and back up about 3-5 ft let off the gas and at the same time, move the stick.  Sometimes I had to do it twice.  But it always worked.  I'd never thought of raising a wheel but that sounds simple enough - although maybe a bit more time consuming while on the road.

I don't believe removing the drive shaft is the solution, and hopefully using the above advice, you're able to unwind and shift back to 2WD.  A stuck shifter is a problem that should be resolved vs. leaving it.  You need to be able to shift.  Hopefully, you are able to unwind successfully.  HELPFUL TIP: I always push the transfer case sticks to 2WD Hi (in your case - the one stick) before driving to make sure! (same as transmission in neutral before starting).

To add to BillT's comment, I believe the OUTSIDE wheel is turning faster than the inside wheel due to radius.  The differentials automatically correct for this but when you're in 4WD, you're adding another layer of binding that eventually winds up the drive train.  As stated soft/slippery surfaces should allow the tires to unwind on their own.  I experienced this first hand in my XJ on patchy roads in KS.  They would scuff when I'd transition from icy to dry patches on the road (in turns of course).

I did google this and found an interesting article explaining this.  What was new to me was the 4 different radius' during a turn in 4WD (follow the link at the bottom for more info):

http://4x4abc.com/4WD101/def_turn.html


« Last Edit: March 21, 2021, 12:20:18 PM by Rus Curtis »
'54 CJ-3B "Green Gruntt"
Bantam T3-C

Offline Bruce_W

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #7 on: March 21, 2021, 02:27:55 PM »
Thanks for the link Rus, that’s a good explanation but it stops before it’s done.
For Steve and others:
As explained, in a turn, the front wheels travel further and need to turn faster than the rear ones. This means that the front driveshaft has to turn faster than the rear one. This is no problem in 2WD as the two driveshafts are not connected to each other, only the rear is driving, and either one can turn faster or slower than the other one. But in 4WD the two driveshafts are connected together in the transfer case and must turn at the same speed. So the faster shaft is trying to turn the slower shaft at its own, faster, rate. Steel is not rubber, but it does have some “stretch/rebound” in it. If you can imagine a rubber driveshaft, you would see how both of them would be twisted. And not only the driveshafts but the drive gears, differential gears, axle shafts, hubs, wheels and tires are all subjected to this force. On slick surfaces, the tires can slip and relieve that stress. On dry hard surfaces (pavement), it’s harder for them to slip, maybe to the point that something else has to give. All it takes is for one wheel, any wheel, to slip to relieve it.
As to the transfer case, the only parts involved are the two output shafts and the sliding coupler that connects them in 4WD. With one shaft trying very hard to turn the other, the coupler has a lot of pressure on it, and that’s why it’s hard to shift out of 4WD. None of the gear train in either the transfer case or the transmission are involved.
  Sorry about the long post, but I hope it helped.
BW
Until We Jeep Again...........

Offline Rus Curtis

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #8 on: March 21, 2021, 04:45:45 PM »
Thanks for the link Rus, that’s a good explanation but it stops before it’s done.
For Steve and others:
As explained, in a turn, the front wheels travel further and need to turn faster than the rear ones. This means that the front driveshaft has to turn faster than the rear one. This is no problem in 2WD as the two driveshafts are not connected to each other, only the rear is driving, and either one can turn faster or slower than the other one. But in 4WD the two driveshafts are connected together in the transfer case and must turn at the same speed. So the faster shaft is trying to turn the slower shaft at its own, faster, rate. Steel is not rubber, but it does have some “stretch/rebound” in it. If you can imagine a rubber driveshaft, you would see how both of them would be twisted. And not only the driveshafts but the drive gears, differential gears, axle shafts, hubs, wheels and tires are all subjected to this force. On slick surfaces, the tires can slip and relieve that stress. On dry hard surfaces (pavement), it’s harder for them to slip, maybe to the point that something else has to give. All it takes is for one wheel, any wheel, to slip to relieve it.
As to the transfer case, the only parts involved are the two output shafts and the sliding coupler that connects them in 4WD. With one shaft trying very hard to turn the other, the coupler has a lot of pressure on it, and that’s why it’s hard to shift out of 4WD. None of the gear train in either the transfer case or the transmission are involved.
  Sorry about the long post, but I hope it helped.
BW


Like I said...  Good stuff!
'54 CJ-3B "Green Gruntt"
Bantam T3-C

Offline SteveKfl

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #9 on: March 21, 2021, 06:37:33 PM »
OK, thanks all.  I never would have thought of it like that.  My closest experience would be 2WD with a spool or locked rear end for racing.  Trying to steer the car to "turn" like in the pits, and with only 2WD in the rea, is next to impossible if the inside tire can't "slip/chirp" some.  With "windup" and also the "monkey grease" needed, I am not  qualified for 4WD.  :-)  Thanks for taking the time for posting explanations and links.  I love this site. 
My Concept Roadster
62 DJ3A Dispatcher Half Top

Offline patrickt

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #10 on: March 22, 2021, 01:48:13 PM »
Rus Curtis, BW, BillT-
                                    Thank you for the link and the more thorough replied.

                  I think i have a clearer understanding now. I did do as BW said, and just raised one front wheel, and saw a  bit of reactive movement from that wheel, just as soon as it (barely) left the ground.

                  I apologize though that I failed to mention one thing, that i in fact could get the transfer case shifter out of 4 wheel drive, but only into neutral, but am unable to get it back to 2 wheel high. Sorry, I should have caught myself earlier.... Regardless, I still could not go from neutral on the transfer case and back to 2 wheel high, after I raised that one wheel.

          And yes, I absolutely agree that removing the front propeller shaft is not the solution, but wanted to do it as a temporary fix so i could drive the jeep to our local DMV for its yearly registration. Thanks again.
                                                                     Patrick

 

Offline patrickt

Re: Ok to drive in 4 wheel drive without front propeller shaft ??
« Reply #11 on: March 22, 2021, 02:11:33 PM »
Oh, just for good measure,let me add that this is a transfer case with only one shift lever. And that the shift pattern is such that you first go into neutral from either 4 wheel high or 4 wheel low, then on to 2 wheel high.