Most of you XC owners out there may have gotten in the mail recently an amendment to your V70 XC owner manual from Volvo concerning tire wear and rotation. Follow the guide line religiously! Failure to do so can cause damage to the drive train!

The problem is having different size tires on the front verses the rear (one tire worn out and the other tire with a lot of tread life left). I have always been a nut when it comes to tire wear and rotating my tires (I like to get the most out of a tire). This past weekend I rotated my tires due to a re-alignment of the front end. What I noticed was a reduction in harsh shifting (3rd to 4th gear). The harsh shifting did not go away but was greatly reduced. Scratching my head wondering why this would be so? What I notice was I had the tires with the most tread life on the front and the tires with the least amount of tread life on the rear. The Volvo manual supplement recommend that if you have tires that are not the same size (I guess one tire with no tread as to the other tire with some tread) you should put the tire with the most tread on the front end. I am now quoting from the Volvo Supplement

"The tires with the least wear and the largest circumference must always be on the front"

This is what I did this past weekend when I rotated the tires and notice a reduction in harsh shifting (3rd to 4th gear).

I believe what is happening with different size tires is that that a drive train binding is occurring due to the front rotating at a different speed then the rear. This tension/binding can effect the shifting quality of the transmission and may damage the transmission and the all wheel drive system. Again I quote from the Volvo Supplement:

"Caution:"

"Failure to always drive on properly inflated, identical tires of correct dimensions may result in a circumference difference between tires on the front and rear axles. This will cause excessive tire wear and may damage the transmission and all wheel drive system."

I also believe that some XC are more sensitive to this issue then other XC.

If you got the supplement follow the guide line it may save you some trouble and expensive repairs down the road. If you did not get the supplement I recommend that you get one and follow the instructions.

Welcome to the Club,

I know just how you feel. Just when you are about to shift into 4th gear you let your foot off of the gas pedal and WHAM! The whole car shakes as if you hit a pothole. Another symptom I noticed is a rough shift between 3rd and 4th gear when the transmission is HOT (been running awhile). And the last problem is a shutter. You are driving at 55 mph; you put your foot on the gas pedal and the car shutters.

There are 3 problems here and they should not be confused. Problem #1 is the transmission fluid. Volvo has stated to me (I had a "Long" talk with two factor reps and an actual Engineer from Sweden) and in a service bulletin (http://www.nhtsa.dot.gov/, look under problem & Issues) that the transmission fluid can be burned (i.e. worn out, no longer has the quality of a hydraulic fluid). When this occurs your toque converter lock up no longer works as designed. This is best notice when you are driving between speeds of 50mph and 80mph(in my case 55mph is the best speed to notice the problem). You will notice a shutter every time you put your foot on the gas. It is like running over a row of small rocks. This problem can be fixed easily by flushing the transmission fluid. Volvo told me that there is no long-term damage done to the Transmission if any damage was done at all.

The Second problem is of a poor design and can not be fixed. This problem is as I described above. Just when you are about to shift into 4th gear you let your foot off of the gas pedal and WHAM! Your assessment of the problem is correct.

"It seems the accumulator cannot react quick enough if the throttle is released just before a shift is to occur, and the whole drive train shudders and bangs with the harsh shift".

This is a design problem and can not be fixed unless you get a whole new transmission. Preferably not of the same design that is currently in your car (i.e. a replacement transmission will not fix this problem).

And the third problem is a rough shift between 3rd and 4th gear when the transmission is Hot (you have to be driving awhile to notice this problem). Volvo (i.e. the Volvo Engineer and the 2 Factory Reps) believe that the torque converter does not unlock at the correct time when shifting between 3rd and 4th gear thus causing the "Cluck" (it unlocks a little to late). This is a toque converter lock up issue and can be related to problem #1. This is why your Dealer is into transmission fluid flushing.

The dealer, Volvo factory Reps and the Volvo Engineer took my car apart trying to figure out the problems 2 and 3. They check all electrical systems, we flush the transmission 4 different times and went as far as to install a new valve body (this unit controls the shifting). The final results were no change. The dealer technician and myself went and drove several XC of different years and found that all 1998, 1999 and some 2000 had problem 2 & 3. Some 2000 XC don't have this problem due to a 5-speed transmission (A different design).

Therefore, the conclusion I have come to is Live with it. One other note I would like to mention. I nailed Volvo to the floor by asking: "If these problems (all 3) do not cause any long term damage and will not lead to a $3,000 (yep you got it!) Transmission replacement for the next 100k miles then I would like Volvo to extended just the transmission warranty beyond 4/50,000". The answer I got was to sell me the extended warranty package at 1/2 price. I walked away from the offer. I felt their response was insulting. My wife and I decided to kee the car until the Factory (4/50,000) Warranty was up and buy a new car. My feelings are that the drive train can not last long being slammed around. Something somewhere is going to give out and I will be stuck with the bill! I had high hopes when I bought my Volvo thinking I had bought a car of high quality. What I got was a poor combination of drive train technology (Volvo engineering of a Japanese Transmission, Volvo transfer case, Germany drive shaft (Silicon gel pack) and a Volvo diferential)and a lot of worry as to if/when it will all fall apart. I do not like driving around thinking something is going to die/break at any moment.

Oh I almost forgot about the upper engine mount breaking. Mine broke too! I do not buy Volvo's explanation. They told me the same as they told you. Your explanation seems to fit.

Good Luck and Best Wishes, Steven---

Hi Chris,

After complaining the very same issue when my 2000 XC was in for its 24,000 Kms service, they also did a complete tranny flush. Apparently they now use a Dexron III-G type of oil, which is part of a service bulletin for us, XC owners. Anyways, that was a week ago and all I can say so far is it didn't help at all. Still intermittent harsh cluncking shifts. I wonder if any of the AWD components are part of this? But the best of my knowlege says it must be torque converter related. I can feel that "clunck" from the seat of the pants. The whole cockpit shakes. Scary... Glad it's a lease althought still 2.5 years to go (hopefully in a single piece!)