QuestionQUESTION: I had a 95 pathfinder with a factory rebuilt transmission and brand new radiator installed at 110,034 miles and i bought the truck at 112,109 miles and have taken very good care of it until the tranny went. i believe the tranny went due to the 2 brandnew bfg hybrid tires sears put on the rear while i had 5/32 tires on front of a different MFG style, pattern (rears had 16/32 at time the front had 7/32 on one side and 10/32 on the other front side). My tranny tech told me the planetary gears all had teeth busted off which was probably due to the mismatched tires. He also said front + rear transfercases or differentials were in need of rebuilding too, also because of tires. I had bought 4 tires from the store about a year and a half before 2 got nails in sidewalls.... i asked the manager of the tire place if i should get just the 2 bad tires replaced or all four since my manual said the tires should be replaced in sets of 4 in 4x4 models..., he told me it was a myth and promised it wouldnt hurt anything on my vehicle. 6 weeks later my truck was viberating like hell on earth and never stopped, when in 4x4 it wouldnt slip in very easily and req'd many trys, 4x4 viberations were worse than when 2 wheel drive, when in 2 wheel or 4wheel drive the truck shifted very poorly and i would have to cycle the shifter from park to rev to nuetral to drive and back to nue then rev then drive then park..... just to get it to turn wheels in any gear.
My question is should the tire dealer had suggested that i replace all four with matching tires since it was 4x4 vehicle? had i done that would I still be driving it instead of it sitting in the salvage yard? wHAT OBS CODES FOR THIS VEHICLE WOULD BE CONSISTANT WITH DAMAGE CAUSED BY THE MISMATCHED TIRES?
THANK YOU VERY MUCH, IN ADVANCED, FOR YOUR TIME.
ANSWER: Mark,
There are a couple of different things that are important to the discussion. First is the type of 4 wheel drive system.
Some 4 wheel drive systems are only engaged manually - that is, you have to put the vehicle in "4X4 mode" to get the 4 wheel drive. Different diameter tires would not affect the operation of the vehicle UNLESS the 4X4 feature is selected.
Some 4 wheel drive systems are part-type and only engage when the system senses a difference it speed between the front and the rear. Those MAY be affected by differences in tire diameter - it depends on the sensitivity of the system.
Some 4 wheel drive systems are full time (usually called All Wheel Drive") and those are continuously engaged and may or may not be affected by differences in tire diameter - it depends on the sensitivity system.
You need to do some research to find out what kind of system you have.
- BUT -
You mentioned the transfer case - and if your system uses a transfer case, then you have the first kind (the other kinds use a center coupling of some sort) - and the only time there would be an issue would be if you engaged the 4X4 feature - and the only time you would do that is when there is a slippery condition and the differences in tire diameter would cause tire slippage and make the vehicle difficult to control. If you have a failure in the drivetrain, it would occur while you are in the "4X4 mode".
- AND -
You mentioned that not only was the problem in the transmission, but you could get the system to work if you cycled the transmission selector. This sounds like a transmission problem and not a problem in the transfer case. The transmission doesn't know what happens downstream of it, so if there was a problem caused by differences in tire diameter, it would occur in the transfer case, not the transmission.
Codes? Those would be specific to the particular vehicle and my expertise is in tires, not vehicles, so you'll have to find that information elsewhere.
---------- FOLLOW-UP ----------
QUESTION: Yeah its not All Wheel Drive, its 4wheel drive and has to be engaged by the driver. Typically I use my 4x4 about 50% of the time because I used this truck to go on the beach and to hunting on a friends land which requires dirving in 4x4 for about 2.8 miles in and again on the way out. Now I hadnt used my 4wheel drive much in the last 3 years, but since I have had extra money since november 2011. So the 4wheel drive was used mostly in Nov, Dec 2011 and then from Jan till May (then is broke).
When you said "Some 4 wheel drive systems are part-type and only engage when the system senses a difference it speed between the front and the rear. Those MAY be affected by differences in tire diameter - it depends on the sensitivity of the system." .... your not talking about posi-traction are you? Because I know or thought think that i was told the 4wheel drive in this truck as well as the 2wheel drive both have the posi traction for each axle.
If this is correct than the difference in size definitely caused the differential damage and im sure the transmission damage as well. Would you agree?
JUST BEFORE THE TRANNY QUIT ON ME I WAS ACTUALLY IN 4X4 MODE DRIVING DOWN THESE POWERLINES ACCESS ROAD BEHIND MY TECH SCHOOL.... IT WAS HARD TO TURN AND NEARLY IMPOSSIBLE TO KEEP ON THE BEATEN TRAIL..... AS I CAME UP TO A SPOT WITH MUDD ON ONE SIDE OF THE TRAIL ONLY, I STARTED TO SINK IN THE SOFT EARTH AND HAD TO REV UP QUITE A BIT TO GET THROUGH IT.... THEN JUST AS MY REAR TIRES WERE EXITING THE MUDDY AREA, THERE WAS AN AWFUL NOISE AND
THEN THE 4X4 WAS AS IF IT WAS IN NEUTRAL.... ONCE I DISENGAGED THE 4X4 TO 2X4 I COULD MOVE, BUT IT WAS HARD TO GET THE SHIFTER OUT OF 4X4 AND THEN TO GET THE TRANSMISSION BACK INTO DRIVE WAS ALSO VERY HARD! I KNEW SOMETHIN HAPPENED. SO I DROVE TO MECHANICS AS SOON AS CLASS WAS OUT.... BARELY MADE IT... WHEN I PULLED INTO MECHANICS YARD, I COULDNT GET TRUCK IN PARK.... HAD TO MUSCLE IT INTO NEUTRAL AND THEN SHUT IT OFF.
SEARS DENYS ANY LIABILITY AND SAYS ITS IMPOSSIBLE TO HAVE EFFECTED OR CAUSED TRANNY/TRANSFER CASE AND DIFFERENTIAL WHAT-SO-EVER..... THEY SAID I NEED TO PROVIDE DOCUMENTATION THAT SHOWS THE TIRE SIZE DIFFERENCE "COULD HAVE POSSIBLY CAUSED THAT TYPE OF DAMAGE".... DO YOU HAVE ANY RECOMMENDATIONS?
THANKS AGAIN
MARK
AnswerMark,
Thanks for the additional information.
Since you have a 4X4 that has to be engaged by the driver, then the transmission and transfer case are separate units. Any problems caused by the difference in tire diameter would manifest itself in the transfer case and not the transmission.
The additional information you supplied supports even more that the problem is the transmission - and it sounds like it failed during a situation of high stress for the trans.
My conclusion is that it wasn't the difference in tire diameter that caused the transmission to fail.
My recommendation is to see if the transmission had a warranty and what it was.
The second recommendation would be to believe the owners manual, even if someone else disagrees. What I am trying to say is that there is a reason why the manual - and everyone else - says to have 4 identical tires on 4X4's and AWD. The guy at Sears was wrong to make that recommendation, but unfortunately, that didn't cause your problem.
