Bitumen driving in 4wd...damage ???

Dunco,
Cant see too much damage to the bitumen being done, its pretty robust stuff.

If a really hot day it may scuff up a little.....hahaha.


Cheers....Lionel.

When i accidentally bumped mine I picked it up because the tyres scrubbed on turns and felt like the power steering wasnt working.

Certainly would have noticed it well within 60km.

Can wind up the diffs and sort of lock it in.

Not sure what sort of damage CAN be done.... but have done it plenty of times in Hulux and Forerunner. Different distances and no issues.

Also had only one wheel locked in in landcruiser while 4wdriving... didn't work well, but no probs.

I think the biggest problem is 'dif wind up', but any little bump or looseness on edge of the road etc should allow this to be compensated for.

More tech stuff my follow!

Do you mean with the front huibs locked in?
No harm caused by this, except a hardly noticable increase in fuel consumption. In fact you should plan to drive with the front hubs locked in (but left in 2WD) for at lease 20 kilometres each month to keep the front drive components lubricated.

If you mean, with the hubs locked in and the selector in 4wd, this will make it harder to steer on bitumen. On unsealed surfaces and sand, each front wheel can "slip" independently of each other but on bitumen both wheels are turning the same amount. Continued use will cause excessive wear on tyres and place additional strain on the diff and front axle. But you should soon notice the difficult stearing.

Bill

Thanks everyone.

Apparently she only noticed it when she drove into the servo and the steering felt funny...she then saw the 4WD light on.

It was on the highway, so she apparently didn't notice it.

All sounds good, I will pass the info on.

Thanks troops.

I did this with our cruiser, only drove about 7kms before I realised.I jacked the front wheels up and noticed "unwind" of about 10mm.
I asked this question on a forum and one guy said he drove about 150kms in 4wd on the bitumen and didnt hurt anything.And he had the vehicle for another 100000kms before selling it.All in 100 series cruisers.

Are you talking about the button for the centre diff lock or what??

if its a full time 4wd and a button was accidentley bumped, then i would say a diff would be screaming for mercy on a bitumen road.l....lol.


Cheers Axle.

Dunco,

I am astounded that nobody has mentioned transmission wind-up. There is no problem if the hubs are locked in, the problem comes when engaged in 4wd on a hard surface. Like it or not, the front and rear wheels rotate and different speeds. There is no diff built into the transfer case, so the only way the different speeds can be dissipated is for the transmission to wind up, including the tail shaft. If your vehicle doesn't have a diff at the transfer case (which most don't) then you are at risk when in 4wd on hard surfaces. Having said that, a friend's wife drove 160 k's in low range, wondering why it was screaming and no damage. There are heaps of posts on transmission wind up. It is only usually a problem when on bitumen, because most other surfaces allow enough slip for the wheels to correct themselves. i am told there is a Toyota dealership in the high country with a proudly displayed tail shaft twisted up like a piece of liquorice twist.
Keep the shiny side up.
Ferris

Transmissions are fairly solid. Back in the 50s the army instructions said tow trailers in 4WD (despite the fact LR did not.) A group of SAS members towed some trailers north from Perth with Land Rovers. They got up near Broome before damage started to show up (diffs I think - this was related to me by a work college back in the early 70s. It happened whilst he was building airports up that way.)

PeterD

Dunco,
There have been some interesting replies to your question, there are a couple of answers that have me at a loss for words.

To clarify your question, does the vehicle have free wheeling hubs and were they engaged when the vehicle was in 4WD on the bitumen? Is the vehicle a constant 4WD?

I think more information is required before giving a measured answer.

Windup will destroy the weakest part of a driveline and I agree with Ferris that there will be indicators of the condition. The first follow up to that seems to be a little blunt.

Cheers,
Wayne.

Had to put my vehicle in 4WD at the dump a couple of months ago after rain and forgot to take it out of 4WD. the next fairly tight corner at the lights down the road .... crunch!
I wasn't sure what it was but the next weekend up at Double Island point with a trailer on guess what.... no 4WD. I'd accidentally left it in 4wd a couple of times before but this time it happened. So the moral is .. don't drive in 4WD on bitumen in part-time 4WD. Still haven't had it fixed yet.