Prospective VX owner looking for a little advice & direction

[Roody650i]

If the TOD system is working as it should at a stop there should be no power going to the front wheels (I know, DUH!). When you start to move there should be no power to the front wheels until about 10-15 mph. At that point you should see the first light on the front wheels light up on the TOD display. There really isn't any way to tell if there is actually power going to the front wheels though. I can never feel the shift in power during normal dry driving. The only way to make sure that the TOD works is to get the rear wheels to slip a little (maybe that snow storm you were talking about). Find a patch of ice/mud/slick road and step on the gas. If the TOD is working correctly you should see all three of the lights on the front wheels of the TOD display light up and you should feel the front end grab. You might also hear the transfer case whine a little. The power shift should only last a split second unless the rear wheels start to slip again, at which point the TOD will throw power to the front wheels again.

When I first got my VX I thought that as the rear wheels started to slip that the TOD would throw power to the front wheels and leave it there. That isn't the case. It sends power forward in short bursts. Just enough to stop the rear wheels from slipping and then it pulls the power back. I live in Colorado and I love the TOD in the winter. As others slip and slide as they take off from a light I can just stomp on it and the TOD takes care of the rest; pulsing power to the front wheels as it's needed.

To be safe, I would also shift the VX into 4 wheel low to make sure that everything works with that too. That won't tell you if the TOD system works, but it will tell you if the four wheel drive system works and that the transfer case is working.

Good luck and keep asking as many questions as you need to.

So the TOD system essentially is AWD? In addition to 2WD/4WD/4WD-Low my Avy has "Auto 4WD" which functions as an AWD system would, sending power to the front wheels when it senses the rears slipping. TOD sounds similar but it only does it if the rears continue to spin, not if they gain traction?

Good luck !
As long as nothing major needs done, that $5200 sounds fair. See if he has records of the timing belt service. If no records, I would certainly talk him down a bit on the price.

Also, check the wheels for excessive peeling chrome. If there is any chrome peeling up at the tire/wheel bead sealing surface area then you'll likely be plagued with air leaks. Usually bead sealant works well but I've had it fail on me a couple of times so far. Maybe take a tire gauge with you to check the air pressure in each tire real quick. Obviously, a low tire will tip you off that something there isn't right.

These wheels are hard to get in good condition. Stock size aftermarket wheels are few and far between.

Things that tend to rust out first would be the license plate lights. In the rust-belt area, those light sockets and their bracket go first and they are not easy to fix properly compared to a lot of other vehicles. Next to go tends to be the front bumper, under the plastic cladding.


None of these things would stop me from buying this vehicle, especially if you talk him down to $4500!!! It's nice to know this stuff first so you can budget for the repairs later.

Didn't inspect the wheels to closely (hadn't yet read about the peeling/sealing problems) but did notice a little rust drip around where the license plate would be. All too familiar with under-the-cladding rust! Some early-year Avys are getting this under the front bumper as well. Only real way to tell is to pull the bumper off, though...same goes for the VX?

Thanks again everyone!

[tom4bren]

The TOD uses electric clutches to pulse power to the front when needed. It won't lock in the front drive train continuouslly so it's OK on dry pavement. I'm not sure how the other full timers do it (probably clutches or viscous coupling). The TOD senses both wheel spin and engine torque when it decides to send power up front. So on your test drive, don't take it easy on the skinny pedal. I wouldn't worry too much about what the TOD lights mean ... just that there's activity on the display when you punch it.

BTW, the rear is posi so you'll get pretty good traction even if the front drive isn't working. I put locking hubs on mine & can't remember the last time I locked them.

BTW, if you're looking for the VX to be an economical DD to replace the Avalanche ... think again. You'll probably only get 15-17 mpg in it. I drive 100 miles a day so the VX stays at home on work days.

[MSHardeman]

Yeah, what Tom said about the TOD (Torque On Demand) system. It is considered an all wheel drive system.

One other thing to look at (and this isn't a deal breaker) is the front bumper on the VX. It is a tube that is hidden behind the front cladding and you can easily see it (if it's there) by looking into the front wheel well in front of the front tire. The bumpers are notorious for completely rotting away. Many people know that there's are gone and drive on, some probably don't know that it's missing and continue to drive. It does nothing for the performance of the VX but would provide some (VERY minimal) front end protection in a crash.

Some pics of mine before I replace it:




Pic of the one that I had built:


Keep the questions coming.

[VX KAT]

A few years ago, several of us put together a pretty detailed "checklist", with many items being very specific to the VX. It's NOT all inclusive, but it's a good place to start, just pick and choose what you want from it. (for example, the front bumper bar rusting out is on there, which Mark just mentioned).

http://www.vehicross.info/forums/sho...9&postcount=10

[Roody650i]

The TOD uses electric clutches to pulse power to the front when needed. It won't lock in the front drive train continuouslly so it's OK on dry pavement. I'm not sure how the other full timers do it (probably clutches or viscous coupling). The TOD senses both wheel spin and engine torque when it decides to send power up front. So on your test drive, don't take it easy on the skinny pedal. I wouldn't worry too much about what the TOD lights mean ... just that there's activity on the display when you punch it.

BTW, the rear is posi so you'll get pretty good traction even if the front drive isn't working. I put locking hubs on mine & can't remember the last time I locked them.

BTW, if you're looking for the VX to be an economical DD to replace the Avalanche ... think again. You'll probably only get 15-17 mpg in it. I drive 100 miles a day so the VX stays at home on work days.

MPG isn't a worry, it's the mileage I'm putting on the Avy that worries me. I've had more things go wrong on that truck over the last 30k miles than I thought possible (ABS sensor, ABS pump, right front wheel bearing, left front hub assembly, O2 sensor, 2 exhausts, left rear caliper, right rear brake assembly, etc...and I still have no AC and heat only if the truck is in a good mood) so it's not bad to let it sit a couple days a week. 15 MPG doesn't bother me...no fun things in life get good MPG Except maybe a Tesla or a 'Vette in 6th on the highway

Yeah, what Tom said about the TOD (Torque On Demand) system. It is considered an all wheel drive system.

One other thing to look at (and this isn't a deal breaker) is the front bumper on the VX. It is a tube that is hidden behind the front cladding and you can easily see it (if it's there) by looking into the front wheel well in front of the front tire. The bumpers are notorious for completely rotting away. Many people know that there's are gone and drive on, some probably don't know that it's missing and continue to drive. It does nothing for the performance of the VX but would provide some (VERY minimal) front end protection in a crash.

Replacing the bumper beam isn't a problem! I can handle that easily. Have a full machine shop at work to do whatever I need.

A few years ago, several of us put together a pretty detailed "checklist", with many items being very specific to the VX. It's NOT all inclusive, but it's a good place to start, just pick and choose what you want from it. (for example, the front bumper bar rusting out is on there, which Mark just mentioned).

http://www.vehicross.info/forums/sho...9&postcount=10

Thanks for the link! Will read up on it tomorrow after tonight's festivities...