4 wheel drive hopping/jumping

[Irishmic]

4 wheel drive had worked before summer, never used it again until today. Did some work on it and thought i would gave it a test, it was hopping/jumping when driving it. There is no issue like this in 2 WD. I was not able to get it up past 5 MPH as it felt so bad.

1980 k5, 6 inch lift, 35/12.50/18 tires. locking hubs were engaged, it was driven down my dirt driveway and onto street, drove it like 75 feet on pavement and stopped. Got out unlocked hubs would not shift into 2WD. I had to put it in reverse for a few feet and it came out. Pulled back into driveway, tired 4x4 again going up the hill, hopped the whole way up, digging up the dirt a bit. It's like the wheels are sticking, that's the best I can explain it. Feels so much like sticking wheels, like if I gave it some speed it would "unlock". However, I also don't want to gas it and break something since I'm not sure at all what it could be.

Anyone ever seen this issue? I hope it's not needing a complete new transfer case but hopes are worth as much as the powerball ticket I never purchased.

Any thoughts on this issue appreciated.

 

[Bent77]

Do any work on the differentials, like maybe a gear set?

 

[Irishmic]

No, no work on any of that, fixing window switches, roof, back window. Nothing to do with the driving of the truck. Has not had any work done on it since spring, when 4x4 was working. Nothing happened to it, no hitting anything or has not been off road. Just been driving it around town. Nothing major.

 

[Irishmic]

As far as the 4x4 working I just had tested it a little. Drove it round my back lawn, up a hill. That's all I used it and did not have this issue

 

[Kain]

look at your axle u-joints

 

[Irishmic]

I did check and they look like what they were before, at least I don't see an issue. Here are some pictures +±

 

[Kain]

mine did this 2wice once the front drive shaft failed and you could move the slip joint up and down over 4 inches
the second was the wheel u-joints and i had to get it in the air and spin by hand to see those

Take the front shaft and grab it at the slip joint and see if it moves up and down while still bolted in place

 

[Irishmic]

Up and down you mean from the ground to the sky and not the front to the rear?

 

[shady]

Just an odd question, but how much different is the tire wear from front to back. If you get a bunch of wear on front but not so much on the back it may start binding.
No idea if it'd be that severe, but it can happen

 

[Irishmic]

No, it does need new tores but they are all about the same, if anything the back driver sode has a bit more ware out of the 4.

 

[Irishmic]

When looking around I find reports of an issue like this. On a Toyota forum people were saying the ujoint. I would be happy with that as it's not too much to fix from what I see.

 

[Desert_K5]

Sounds like wobble from d shaft angle out back? Maybe shackles up front?

 

[skunked]

Have you pulled the diff covers to verify both axles are geared the same? Axle u joints would be my second suggestion and you won’t know if they’ve failed until you pull the axle shafts.

 

[rampage]

Have you pulled the diff covers to verify both axles are geared the same? Axle u joints would be my second suggestion and you won’t know if they’ve failed until you pull the axle shafts.

I thought you could check them by jacking a wheel off the ground and with the wheel turned to full stop rotate the tire and see if it turns freely without sticking anywhere.

 

[Irishmic]

Have you pulled the diff covers to verify both axles are geared the same? Axle u joints would be my second suggestion and you won’t know if they’ve failed until you pull the axle shafts.

I habe not pulled them off, is that a fairly easy thing to do. I'm pretty green. Most work I habe done on this is basic, fixing heater, switches bodywork, 02 sensors. I will look into what that would be.

From what I found if I habe to take ot to a shop to swap the ujoints that would be pretty simple and not too much, am I correct on that?

There is a shop by me who works on a bunch of squarbodys and he has replaced rotors. So I feel comfortable with his work. Plus he is a friend of a friend.

 

[rampage]

I habe not pulled them off, is that a fairly easy thing to do. I'm pretty green. Most work I habe done on this is basic, fixing heater, switches bodywork, 02 sensors. I will look into what that would be.

From what I found if I habe to take ot to a shop to swap the ujoints that would be pretty simple and not too much, am I correct on that?

There is a shop by me who works on a bunch of squarbodys and he has replaced rotors. So I feel comfortable with his work. Plus he is a friend of a friend.

If you’re talking about the axle shaft u-joints, then it can easily become an expensive job because you need to basically remove so much to get to them. So as long as you’re that far you might as well do the ball-joints, races/bearings, brakes/rotors. But that’s just how I’d do it depending on their condition/life.

 

[skunked]

I thought you could check them by jacking a wheel off the ground and with the wheel turned to full stop rotate the tire and see if it turns freely without sticking anywhere.

You can however this is a new truck (to him) so pulling the covers and replacing the gear oil might have been something he’s already done.

I habe not pulled them off, is that a fairly easy thing to do. I'm pretty green.

Pulling the diff covers is very easy.

 

[Irishmic]

If you’re talking about the axle shaft u-joints, then it can easily become an expensive job because you need to basically remove so much to get to them. So as long as you’re that far you might as well do the ball-joints, races/bearings, brakes/rotors. But that’s just how I’d do it depending on their condition/life.

Already did breaks/rotors and ball joints about 5 months ago ‍

 

[Wes Harden]

are all the tires the same brand and size? even the same size tire in a different brand will taller or shorter than the next brand. Some time even the same brand but different batch.

The bucking sensation, aka axle Tramp, sometime happens when one axle has gets good traction and the leaf spring starts to "wrap" or twist, then when the resistance of wrap is more the traction of the tire it will spring back, and tramp, or feel like bucking. This can be more pronounced when the other axle has less traction.
So since this symptom wasn't happening when you tested it last, A spring may have broken, or the traction conditions have changed.
I am going to go out on limb here and say that you do not have miss matched gears in your axles, based out your 4wd test earlier in the year. Popping the diff covers and checking, would be purely for piece of mind, knowledge of equipped gear ratio, differential type, and maintenance oil change.
If you have the means to put the truck on body stands, you can check all of your u joints, before seeking repair at a shop.
on level ground, wheel chalk tires for axle not being jacked. Body stands under the axle either front or rear 1 side at time. T case shifted to neutral, turn the drive shaft for raised axle. Feel for stiffness as it rotates listen for popping, groaning or creaking. On the front axle turn the steering all the way to one side lock the hubs, spin the tire, feel and listen for the same signs. If you feel or hear these noises, chances are very good you have 1 or more bad u joints.
If you do find a bad joint, let us know which, and we can help you decide if you want to try to replace or find a shop to do it.

 

[kennyw]

First thing, never run 4x4 on dry pavement. That is a good way to break stuff. Backing up to get back into 2wd is normal when you bind up the system like that.

Have you verified the gear ratio in both axles match?