4 Wheel Drive Ruined by Worn Tires

I have a '07 Dodge Nitro that I have recently purchased. The tires in back were more worn than the tires in front when I purchased them. Obviously, the previous owner has not rotated the tires. I took my Nitro into a GoodYear store and had the tires rotated. The service guy told me that I need to buy two brand new tires to replace the poorly worn tires. The other two tires are practically new. He continued to say that if I did not replace the two worn tires that it will trash my transmission soon. The Nitro is a 4 wheel drive. Is this correct? Any input is helpful. Thanks

It really depends on whether your Nitro has Part-time 4WD or Full-time 4WD.
Both versions were available in '07.

Refer to your Owner’s Manual to determine what is the case for your particular model.

VDC is exactly right. The awd drive version would be less stressed if the tires were close to the same diameter and badly worn tires might not be close enough. It’s just as important theoretically for part time 4wd, but because it’s use is limited to slippery conditions, it isn’t as big a factor as slippage will more likely occur.

If I had a new 4 wd of awd and was told two of the tires are bad (you won’t like this) I’d purchase or make sure the 4 new tires were the same (make,size, model) tread design which I feel is of equal importance, and make sure I rotated before difference in wear was as much as 2/32 " or every 6 months. which ever came first. You want the advantage of 4wd and have it take care of you when needed ? Then you take care of it. The next time we purchase an awd/4wd car/truck, we should negotiate the tire replacement cost with it if needed.

BTW, most manuals that I’ve had on any car/truck 2 or 4wd stress the importance of tires with similar wear and tread design when replacing. Just buying two, might not do it.
Be safe .

If the tires are identical except for wear there shouldn’t be enough difference to cause any undue wear to the drive train. Definitely it won’t harm the transmission. A significant difference would cause the transfer case differential some added wear if it is full time 4 wheel drive. If it shifts in and out of 4 wheel drive tire size has no effect on the drive train when the front is not engaged.

With regard to tire dealers quoting infinitesimal numbers as critical for proper operation, you might ask the dealer where his device is to measure the mounted tires radius. If 1/16 of an inch is critical then the dealer should have the equipment to measure that parameter and adjust tire pressure to bring all 4 wheels to an exactly equal height. But, of course, if your mother-in-law jumps in to ride shotgun you’ll need to re-measure and adjust that pressure to allow for the added weight.

It is part-time 4WD. I must put it in 4WD drive for it to activate.

Plus, I live in flat Indiana. Not many hills or inclines that I have to worry about.

Dealers set tire pressure properly and then measure the rolling circumference of each tire. Very accurate.

As long as you are running around in 2wd it is fine. So no imminent to change them out.

However the long you wait, the more your two “good” tires wear, so the difference between new pair and good existing pair get greater.

It is very stressful to a part-time 4wd drive train to be run on a hard surface with two sets of wheels at different rolling circumference(wear). This is a major downside to both 4WD full-time, part time and AWD.

If you don’t need 4wd, why did you buy one?? As long as you leave it in 2wd the tires are no problem…If you feel compelled to put it in 4wd because the road is a little wet and slushy, the mis-matched tires will be a BIG problem, making the vehicle difficult to drive and stressing the entire drive-train…

My reply was mostly sarcastic. I haven’t calculated the difference in the circumference of two tires with 1/16 inch difference with respect to how few revolutions it would amount to on the differential per mile but it might be very inconsequential. And if it is a 4 wheel drive(in rear drive only, of course) there is no issue.