Dana 18 Not Shifting Back Into 2h

If I'm on pavement as soon as I engage it in 4wd it's binding. On jackstands, no issues

 

Warn

 

If you drive in a straight line for a short distance there shouldn't be any binding.

 

With that wheel dragging an inch is all it takes to bind. That wheel is turning against the springs and frame the surface terrain doesn't matter anymore.

 

But why is it fine in 2WD? Wouldn't the axle be showing symptoms in 2WD?

 

That's the only part that troubles me, but really there is not anything on a d18 driveline that would cause this. The rear is fine in the air and 2wd.

Front rotates freely in the air with hubs locked and t-case in 2wd?
Does it pull when braking?

 

But it's not dragging in 2WD

 

It’s certainly a toughy. I always try to start with the simplest, least intrusive tests when diagnosing a problem. I think I would put it up on jackstands again, go around to each corner and spend some time with it. How does each wheel turn, any looseness or odd sounds, on the front locked and unlocked hubs. Then I would closely examine the T-case shifting linkages. Then I would put some chalk marks on the front and rear drive shafts, start the engine (still securely on jack stands), and put it in 4wd and 1st gear and give it a few seconds of running. After shutting the engine off, check that the chalk marks are still aligned and go back to each corner and examine again. I can’t think of what in the T-case would cause your symptoms, but I wouldn’t rule out anything based on assumptions. After that I would pull the rear cover based on the tire dragging and have someone turn each rear tire while you observed the diff. If I found nothing, I’d do the same with the front. I know you’ve probably done some of this but I’ve had times in the past where I’ve missed things on the first go around. Good luck, you’ll get it figured out.
Tim

 

Are you 1,000% sure the front and rear axle ratios are the same? Reason I ask is because the picture of your rear tire drag didn’t look like a full lockup, but rather a tire just rotating slower than the others. If the gear ratio is close - like a 5.38 in the rear and a 5.29 up front - it may not be noticeable driving slow in loose dirt - so the problem didn’t present itself until you went into 4wd on pavement and had really great traction.

first thing I would do is quadruple check the axle ratios are the same.

 

Stock 5.38 in the back, bought new carrier and ring and pinion and all that in 5.38 for the dana 30 swap last year

 

and you’re sure the ring and pinion you bought weren’t mislabeled? I would put the Jeep on jackstands and rotate the tires while counting the revolutions on the driveshafts to make sure they’re really identical.

 

I'm gonna pull off the diff covers and confirm nothing is broke in there, and they are the same ratio.
I'll try anything before I have to take it in to a shop

 

Backup for a moment and consider the whole picture. I sense growing frustration with all those involved here.

You have a vehicle that is causing you anxiety…one that you have probably taken care of and invested much time and money. We’ve all had similar experiences.

This forum is full of folks, just like you, and some are true experts. There’s no place else you can go for FREE ADVICE when it comes to getting ideas on how to chase a problem with these 50+ year old Jeeps.

It’s easy to jump to conclusions because something ‘seems’ right. However, as many of us can attest, you must be methodical in problem solving. It’s easy to get defensive, but that’s not part of the problem-solving flowchart.

Several have given ideas or starting points. Sure, you’ve put the vehicle on jack stands, only to add to the confusion. We’re all confused!

Take a brake drum off, or two, and have a look. Take the rear differential cover off for an inspection. One more test idea…Pull front driveshaft and shift into 4WD from a stopped position. Drive normally and shift out of 4WD, while moving. Is there resistance? This action should eliminate anything suspect in the transfer case, but again, nobody can be sure.
boopiejones has a great idea...do it, too!

Take more pictures and share your findings.

It’s really difficult to troubleshoot items like this from a distance. Do you have a mechanic friend/contact that can come by and evaluate it from scratch?

 

I agree with this. It sounds like normal driveline windup but it's happening very fast (and without turning?) which means the two axles are trying to turn at different speeds. A flat tire on one end could potentially cause this but for it to be flat enough to do this, it would be obvious. It really sounds like you've got different ratios front/rear.

 

If that rear tire is being dragged the rear ratio at the driveshaft is effectively 2.69:1

We're not frustrated, just anxious to know I'm right.

 

Did you test drive this vehicle in 4WD after the Dana 30 installation?