Truck Locks up Turning in 4-Wheel Drive

[RVGuy]

I haven't owned many 4 wheel trucks and I've never experience anything like this before.

While in 4 wheel "Hi" postion, and when turning either direction full lock, the drivetrain seems to lock up and it takes considerable pedal to make the truck go. And when it does go it launches as if I had released the brake.

And no, I'm not depressing the brake while doing this. tongue.gif

Is this normal operation for this truck??

[battmain]

Yup. Try switching back to 2wd if you have to turn or increase the turning radius so you don't have to turn as hard. I usually switch to 4wd once the trailer is straight.

[ 10-26-2002: Message edited by: battmain ]</p>

[ZFMax]

While turning in 4 wheel drive, the front and rear wheels need to turn at different speeds. With no slip device in the transfer case, you get exactly the symptoms you're reporting.

In general, you don't want to use a locked 4wd system on clear pavement, and you especially don't want to make a turn under high traction conditions. You will tear up the running gear in a hurry. 4wd is for icy or dirt roads only. On patchy icy roads, I'll often go back and forth depending on the condition of the road I'm on at the moment and whether or not there's a need to make a turn.

[ 10-26-2002: Message edited by: ZFMax ]</p>

[RVGuy]

Thanks for the information. I feel much better now. I'll be switching back to two-wheel when making sharp turns.

[letsgo]

RVGuy

As a first time 4x4 owner I had to ask the same question 10 months ago, like you I got lots of good info from the members.

Now I only use 4 wheel drive in snow and when I accelerate in rain from a stop, and when towing into camp sites with either gravel, grass, sand, but not on ashfalt.

good luck

[ThePend]

RV Guy.... Its normal for this to happen. I had an F350 that would do the same thing. Then I found out that you shouldnt engage the 4WD on dry pavement and do a full lock turn, thats a no-no.

Since I dont go off roading very much, I usually wait until it rains and engage the 4WD then to keep everything turning.

[SPICER]

I was climbing a muddy hill today in 4WD. When I got out of the mud I forgot to take her out of 4WD. I drove on dry pavement for about 6-7 miles. I didn't realize it until I took a hard left and she felt really sluggish, like the E brake was on. I turned offf the 4WD. The front diff. felt warm, not hot. I took about 6 turns during this time. The manual simply says that accelerated wear may occur if left in 4WD on dry pavement for a "long time". Any comments, any experts? Ironically I just changed both diffs. a week ago to, Mobil1 synthetic. I have not changed the transfer case yet...6300miles. SPICER :confused:

[dmaxalliTech]

spicer, dont worry about it, if your feel the need, pull your fill plugs and check fluid condition. IMHO, you'll be fine

[SPICER]

dmexalliTech,

Thanks for the reassurance. What would I look for if checking the condition of the fluids?

Just for education sake, what happens if you do run for a "long time" in 4WD on dry pavement? What components take a beating?

And, now that I have your attention, when should I change tha electronic transfer case fluids? I changed the front and rear at 6000mls. and used mobil1(switched out the front vent cap to white also). Thanks, and if you are a dmaxalliTech your oppinion is not humble....it is expert. Use IMEO next time!! :D SPICER

[Jelisfc]

SPICER, the whole drive train gets bound up since almost no slip is allowed. Long term parts would wear out quicker. I doubt the added loads are such that anything would break immediatley. CV and or u-joints certainly would take a beating. Fluids are not a worry.

Real life example. I used to drive a 6x6 military 10 ton semi tractor. A different driver left the front axle engaged. I jumped in and drove down dry pavement. The drive train got so bound up something had to give. The front wheels were trying to turn faster than the rears and due to the added weight on the rears the front end actually started hopping left to right. As it did the tires would break traction and unload the drive train. Heck of a ride when that happened. It was all I could do to stop it from 30 mph.

I doubt that would ever happen on a pickup since the weights are less and more balanced.

[dmaxalliTech]

Spicer, according to the owners manual, Its recommended to change the transfer case fluid at 50k. Use GM AutoTrak II Fluid when doing this part no. 12378508. I have not heard of any other fluid out there that I would be comfortable puttin in my t-case. I would stick with oem on this.

As far as recommended change intervals for axles. I just checked owners manual for that and its never mentioned to change it, just check and top of if necc. This is GM reccomendations. IMEO, I would change out the rear diff at 5k if posi. front and rear at 30k depending on usage. I have switched to BG products 75-90 lube front and rear and was advised that it didnt need to be touched again. In fact,I even got a 250k written warrenty on both diffs :D :D

As far as checking fluid level/condition. Just pull fill plugs and stick your finger in and get some to examine. It should still be nice and clear and somewhat transparent. should not have a burnt smell to it either.

As far as potential damage goes..Typically on a well maintained truck,, it would be minimal. I can see if your driving an army vehicle where trouble would come in!..Assuming that your tires are wearing evenly and pressures are all correct. On 1/2 trucks with automatic transfer case, the clutch pack in the case will slip a little. I have been guilty more then once of driving my truck 20+ miles to work at highway speeds while locked in. I wouldnt run it when turning on dry pavement for any lenght of time regardless though.

[chuntag95]

Dmaxalli Tech, I am pretty sure we don't have an AutoTrak II system. The transfer case uses normal Dexron III ATF IIRC. We went through this about 6 months back. The manual is misleading in this case and many folks were confused. Hoot, Mac, JK, One of you intelligent guys back me up or shut me down. :D I need to change mine again if I'm wrong because I have transynd in it. :eek:

[Kennedy]

No Auto-Trak on HD's.

I've got Transynd in mine...

[britannic]

Just to add that even wet pavement isn't usually slippery enough for 4wd and in fact could even lead to skidding on curves. It's bad enough in the rain with my rear detroit locker on my CUCV.

Unless you have an AWD system or auto 4WD engagement when traction slip is detected, save engaging your 4x4 for muddy off road, snow or when you can't climb slippery surfaces.