Winter driving?

[Ted Brown]

I have recently changed from a 1983 Mercedes 280GE with automatic and manual transfer case to a 2007 XC70. Winter has arrived and I find myself somewhat perplexed at how to drive it. I have read that the xc70 is "great in the snow" so think that I am doing something wrong as I would be hard pressed to agree with that comment based on experience todate.

Today, as an example, I was pulling a trailer with about 1000lb load, 2-3 inches of fresh snow. I climbed a smallish hill and almost at the top the car had slowed down, did not down shift and then came to a stop because of low revs. Once stopped I applied the gas, the transmission shifted down and was able to pull away without problems. I did try to shift to manual at low speed but it did not seem to make any difference.

I am guessing I am not driving it correctly but it may be that the transmission is not operating correctly?

I would appreciate any and all input as to reasonable expectations and tips on how to properly drive it in snow.

Thanks

Ted

[hoonk]

[QUOTE=Ted Brown;202881]Once stopped I applied the gas, the transmission shifted down and was able to pull away without problems. [quote]

Unfortunately it sounds like your transmission is not working properly. (it should downshift by itself when needed) If you recently purchased the car you have found the reason why the car was for sale. The transmissions used in the 5 cyl Volvos are known to have problems.

Sometimes - a valve body will solve those transmission problems, sometimes it takes a completely remanufactured transmission.

Edit - Your car has at least 150k miles on it (from one of your previous posts) - if you still have the original transmission I would expect your transmission to need to be replaced, and I would be very reluctant to TRY a valve body in it to solve your transmission problems.

[MacNoob]

OP has an '07 (like me) - which SHOULD have a decent transmission (unlike 01/02)

Not downshifting sounds maybe like he has it in Winter mode (W button) - that means it starts in third gear and doesn't downshift below that.

In Manual mode (shifter to the left) you will see on the dash which gear you're in.

Towing 1000 lbs uphill in 3" of snow is going to be difficult! It's possible it was SO slippery that the traction control cut power almost to nothing to prevent wheel spin. In this case, disabling the traction control and letting some wheelspin happen might be the right approach.

Snow tires or all seasons on this car? In Quebec you're supposed to have snows I think?

Manitoba weather + 4 snow tires + XC70 = unstoppable. Although we don't have hills!

[Astro14]

You didn't happen to be in "W" mode on the transmission, did you?

That locks it into a higher gear. I don't recommend use of the "W" on the shifter - it really doesn't help much and can cause the problems that you describe.

[Ted Brown]

Car was in D mode when this occurred, I have 4 snows on (Quebec does require this from Dec. 15th onward through March); when I shifted into manual I did see "1" on the dash. I have tried using W mode on a couple of occasions, did not notice any difference but will avoid in the future based on your comments.

I will have to look at the manual to figure out about traction control; it does have a setting for "Comfort" or "Sport" and was in the "Comfort" mode.

I will have my mechanic have a look at fluid level and colour.

(I am aware that carrying 1000lbs is not a best idea but I got caught with early snow here and had not finished up my fall chores (was getting a couple of barrels of salt/sand for a neighbour.)

Thanks for your comments.

[billr99]

You are in "D mode" even when you hit the "W" (that is, winter) mode switch which is located just aft of the shifter. I would suggest reading the manual which reads as follows for the '05s on page 110:

W Winter/Wet driving mode - enhanced vehicle traction
Mode W will only function if the gear selector is in the (D)rive position.
Press the button at the base of the gear selector to engage/disengage this driving mode (see illustration).
An LED in the button will light up to indicate that W is engaged and this will also be displayed in the instrument panel (see page 29).
This mode may be selected for starting/moving off on slippery roads.

You also don't mention what kind of winter rubber you are running. Some are better than others even with AWD. I find that Gislaveds or Nokians work the best, especially if you are driving in the slop like we have here in the Maritimes.

Cheers,

Bill

[Xfingers]

OP has an '07 (like me) - It's possible it was SO slippery that the traction control cut power almost to nothing to prevent wheel spin. In this case, disabling the traction control and letting some wheelspin happen might be the right approach.

This is going to be my first winter in the snow with my 2007. I'm also curious about the DSTC feature. The info I've come across so far seems to suggest that when driving in snow it may be helpful to have the DSTC disabled. My basic understanding is that the DSTC monitors wheel rotation with the goal of keeping all 4 wheels spinning at the same speed. If necessary, DSTC feature will cut power to wheel(s) to achieve this.

There's a thread on swedespeed where a guy couldn't get up the hill in snow because he wasn't able to disable DSTC. (He replaced his DIM with a different model.)
https://forums.swedespeed.com/showth...o-DTSC-Control

To disable DSTC, "The 07 has no separate DSTC button. Turn the wheel on the turn signal stalk until "DSTC On" shows up on the DIM. Press reset button to turn it off."

[Ted Brown]

Bill - I should have been more clear - my display shows either "D" or "W" when in automatic mode. I have pressed the W button on a couple of occasions and also used the manual mode and see "1" or"2" or... the dash display works correctly. I don't know the brand of the snows, will have to check; they came with the car and are close to new so I will continue to use them.

Xfingers - Thanks for the DTSC reminder! My 07 starts in this mode and has to be changed via the turn signal stalk. I am guessing this is the source of the issue I have experienced on a couple of occasions; I will check it out today as the snow has continued to fall.

I will read through the manual for their pointers on use but am curious - do folks recommend disabling DTSC as a routine in the winter or only in "severe" conditions? Winter here is mostly dry snow and lots of it, occasionally we get rain and I do my very best to stay home in these circumstances.

[Ted Brown]

So I just finished reading the manual and have 2 comments - too many controls to worry about and language in the manual is cryptic (no real guidance on when one should be using what). I will figure it out but...

I have Geartronic, Four-C, DTSC along with the more normal Kickdown function of an automatic trans. The manual suggests that each of these have some use in slippery conditions; on how they interact with one another the manual is silent.

[pbierre]

I'm not understanding what you thought was the problem. What were you expecting to happen nearing the top of the hill? What differed from your expectation?

When pulling a 1000 lb. trailer, I'd be inclined to try the Geartronic "manual" mode. If my understanding of this transmission is correct, the shiftpoints when in "D" and "W" are based entirely on sensing the motor shaft speed vs. the load shaft speed. It doesn't sense the load torque in deciding when to shift -- the tranny software doesn't know you're pulling a trailer. Do you think manual shifting would make it easier to pull your trailer?