I'm not really into vehicles (although I do love my 2002 F150 XLT), but I'm hoping someone can help here.

Two years ago, I changed 2 tires to a more agressive tread, for our PA winters. Last year, I changed the other two tires to the new tread. After 1 year, there is a major difference in tread wear (older tires are almost bald).

Local tire supplier told me, a few weeks ago, that running with as little as a 5/32's tread difference between the front/rear tires could damage the transmission because the truck doesn't have slip differential.

Yesterday, the 4x4 started malfunctioning. It didn't want to shift from 2H to 4H. When it did, it didn't want to shift back. Half of the time, I had to use two hands on the floor shift to move the stick from 2W to 4W and visa versa.

I know I'll have to replace all of the tires. (I also need an alignment and a rear brake job.) Can the difference in tread wear, because of wheel rotation speed, cause a tranny problem? Did I also toast the transmission, or could it be something else? Any help would be appreciated...

 

Shoot, i've got 235s on the front of the 88 and ran with 31" on the back fer awhile. 1.5inch i think difference. As long as you are not on dry pavement, there is enough slip in low traction 4x4 situations to not give problems. If anything it will cause binding in the transfer case and not tear up the tranny other than increased load.

Welcome to the forums! Where in NE PA? Is there a problem with yer tranny shifting? Get under and check the transfer case linkage for heavy rust. This can happen with not too often use.

Adrianspeeder

 

HI!... Running two different diameter tires ones set on the front and other on the back will eventually destroy your transfer case. See people do it all the time around here. Also see people with L/S or posi change to a spare tire in the back when they get a flat and wonder why their L/S or POSI is destroyed 20 miles down the road. Some people just don't know any better I guess.

 

is that true???

 

HI!... Yes but only when your in 4X4 mode.

 

i have the same size tires two are new and two are about done i only use it in the snow and when i get stuck in the front yard is that ok

 

You'll be fine.

Adrianspeeder

 

Of course! ......Neal lives in canada, and people ride down the road with 4x4 engaged, and what neal was saying is that when the front tires are different diameters than the back tires, then one or the other HAS to slip. Because the transfer case is expecting the front and back tires to spin at the same speed, but as you probably know, when you get bigger tires, it changes your "gear ratio" so to speak. So if the back tires are bigger than the front, then they don't have to spin as fast as the front ones. And a transfer case doesn't like that! Unless you are on a slippery surface, then your tires just spin. Same goes for putting a spare tire down. If you have tall tires, and put a spare on 1 side, then the L/S clutch is gonna be slipping the whole time, because 1 tire is gonna be spinning faster than the other!

If you still don't know what I'm talking about, remove the rear diff cover on your truck, or somebody's, and turn the wheels by hand. You'll see what I'm talking about.

If you're still in school, pay attention in physics. You'll find that it explains a lot about everyday things. You'll be able to predict what will happen based on your knowledge of physics.

 

I appreciate all of your input. I guess it's time to get this puppy fixed and pay better attention to what's going on where it meets the road. One minor problem turned into several costly ones...

By the way, Adrianspeeder, we're in the beautiful Pocono Mountains, near Lake Wallenpaupack (Northeast PA).

Thanks, everyone!