Problem after changing the front tires

[Philip_1973]

Hi, Today we changes the front tires because it was necessary. The rear ones still have some miles on them.
But as soon as we left the shop there was some kind of shaking noticeable.
First I thought the tires weren't balanced correctly or not tightened properly.
Then I found out that when it is set on 2WD the shaking/issue was gone but when I put it back in 4WD it came back.
So I assume it has something to do with the gearbox.
Before the tires were changed there was no issue so the new tires must have triggered something.

Could it be that the computer is confused because of the difference in diameter between front and back?
Is there some kind of resetprocedure like when you change the oil?
Or do they need to be replaced with 4 pieces at ones?

Any info is welcome

 

[mohemipar]

The PCM will not automatically calculate tire size. It operates under the assumption that the truck has the factory size tires in all four corners no matter what and tread depth is not going to matter. I would be shocked if it was actually your transfer case or drivetrain having an issue. Having two brand new tires up front and two worn tires in the rear is throwing off your balance. The differences in tread between the new and old are probably a lot greater than you think. You can actually cause damage to the transfer case by doing this. You should replace all four tires at the same time especially on 4x4 or AWD vehicles.

 

[Philip_1973]

The PCM will not automatically calculate tire size. It operates under the assumption that the truck has the factory size tires in all four corners no matter what and tread depth is not going to matter. I would be shocked if it was actually your transfer case or drivetrain having an issue. Having two brand new tires up front and two worn tires in the rear is throwing off your balance. The differences in tread between the new and old are probably a lot greater than you think. You can actually cause damage to the transfer case by doing this. You should replace all four tires at the same time especially on 4x4 or AWD vehicles.

Tnx for the reply.

So changing the back tires should solve the problem?

Following that logic it would be unsafe to replace an almost worn out flat rear tire with the brand new spare, even for a while.
For the front you can put it in 2wd like we did, but for the rear?

 

[crash68]

^^^^ what mohemipar said
There is too much of a difference in tire diameter front to rear, your transfer case is giving you the problem.
You can get away with having larger tires on the front or the rear in two wheel drive. With four wheel drive, all four tires need to be relatively the same diameter.
My neighbor had a tire shop put a different size tire on one of his fronts, similar issue where the truck shook bad in 4X4.

 

[Pull Ya]

If your tires are different size on a 4x4 and you end up trying to run in 4 wheel drive be prepared to buy a new transfer case. As has been said, all four tires need to be the same size.
Jay

 

[turkeybird56]

Change all 4, and do not run on spare except for emergency, it is not full size, just for emergency use, just saying, IMHO

 

[Philip_1973]

Ok i'm gonna order another set of tires and hope it will be fixed.
Just hope that the transfer case hasn't been damaged yet.

 

[Philip_1973]

Installed a new set on the rear and the problem is indeed fixed!
There doesn't seem to be any damage to the transfer case because he is doing fine right now.
Learned something new now!
Before the Dodge we had a Volvo XC90, also a 4WD, but changing only one pair wasn't an issue with that car.
Looks like Dodge is more sensitive to this.
Tnx fot the input guys!!

 

[hotrod45]

Hi, Today we changes the front tires because it was necessary. The rear ones still have some miles on them.
But as soon as we left the shop there was some kind of shaking noticeable.
First I thought the tires weren't balanced correctly or not tightened properly.
Then I found out that when it is set on 2WD the shaking/issue was gone but when I put it back in 4WD it came back.
So I assume it has something to do with the gearbox.
Before the tires were changed there was no issue so the new tires must have triggered something.

Could it be that the computer is confused because of the difference in diameter between front and back?
Is there some kind of resetprocedure like when you change the oil?
Or do they need to be replaced with 4 pieces at ones?

Any info is welcome

This is not specific to your question, sorry, but it is direct in terms of addressing your initial action. Whenever tires are replaced on one axle only and the difference in tread depth is either close to or more than half the new tread depth, the new tires have to be put on the rear of the vehicle. The reason for this is that the rear of the vehicle must always be able to do what the front of the vehicle can do. For example, if the better tires are on the front, you could manage to maneuver the front successfully, but the rear will break traction and come around on you. Likewise, the front could negotiate surface water on the roadway, but the rear will hydroplane without you have any feedback in the steering wheel. On any one axle, the tread depth difference applies to each side, too. Too great a mismatch will result in dangerous handling problems.

 

[Philip_1973]

This is not specific to your question, sorry, but it is direct in terms of addressing your initial action. Whenever tires are replaced on one axle only and the difference in tread depth is either close to or more than half the new tread depth, the new tires have to be put on the rear of the vehicle. The reason for this is that the rear of the vehicle must always be able to do what the front of the vehicle can do. For example, if the better tires are on the front, you could manage to maneuver the front successfully, but the rear will break traction and come around on you. Likewise, the front could negotiate surface water on the roadway, but the rear will hydroplane without you have any feedback in the steering wheel. On any one axle, the tread depth difference applies to each side, too. Too great a mismatch will result in dangerous handling problems.

So if I read this correct, if I would have put the new tires in the rear and the old tires up front there wouldn't have been an issue?

 

[hotrod45]

So if I read this correct, if I would have put the new tires in the rear and the old tires up front there wouldn't have been an issue?

My expertise is limited to handling issues arising from mismatch or placement of new/worn tires. The symptoms that might be traced to the 4WD system belong to a topic that the other contributors here know far more about than I know. That being said, however, I can confirm that you now have the best solution, since the performance of four new tires is exponentially better than having 2 new/2 old.

 

[Truck Fun]

Had a friend who replaced either his front or rear tires on a Chevy he had at the time. Whenever he went into 4wd, he had issues. Mechanic put a mark at the same place on the front and rear tire, then drove it a very short distance. Even though the front and rear tires were the same listed size, the diameter was different enough that the marks showed differing travel distances between the front and rear. It was just enough difference to cause issues in 4wd.