Clunk after switching from 4hi

It will do that if you wind the tc up without enough slippage. I get every now and then if I use 4HI to get moving on a slick upslope and turn at the same time onto a reasonably dry surface - think side street onto a main drag type thing. If you aren't going straight ahead, things get wound up and binding real fast. I normally use 4HI just long enough to get moving good and pop it back to 2HI before I even think about shifting out of 1st, especially if I'm going to hit anything that looks like it has decent traction.

It is normal for the tcase to object to this sort of abuse.

What is happening is that you are binding the tcase as you accellerate, then when you shift out of 4WD again, it takes a while for the bound up stuff to disengage. There is no real need to do what you are doing, and you are damaging stuff while you are what it is that yo do not need to do. You should be taking off with a little less gusto ...

Sooo, I shouldn't be using 4wd to pull out of intersections, that, say have an incline and are covered in ice? REALLY? In 2wd, I'd never make it out. I've tried and spin all over the place. Gusto or not.

If you must use 4WD, then shift out of it earlier, and use as little gas as possible.

Your tcase is a chain-driven unit, and when you shift out of 4WD, it takes a while for the gears and such to actually disengage, this is why it takes so long for the clunk to come.

The tcase has no differential capabilities, so the different speeds of the front and rear tires will quickly bind it up to the point that it will not disengage. The length of time it takes to disengage is a sign of how much damage has been done to it, when it is new it should disengage pretty quickly, but as the chain stretches, the time to disengage will become longer and longer.

If you are seeing "normal" cars and trucks getting around town, then you should be able to get around town in 2WD too. If you need 4WD to get going, and you are driving the same as you do in summer, then you are binding the tcase and stretching the chain.

It normally disengages almost instantly. The two times it hasn't was when I came from a stop sign (slick/slushy/snowy) and TURNED onto a road that quickly turned to dry surface that this happened. Guess I'll stop doing that....

I've used it since, and as long as I am not turning onto something paved, it works just fine (i.e. disengages just about instantly).

accellerate,

It's the turning that binds the tcase. As I explained earlier, the tcase has no differential-qualities that prevent stresses from building up, and the front and rear travel different distances, which is what causes the stresses to build up.

I live in sunny Southern California, and have never had to grapple with the problems brought on by snow and ice, but if I took my Jeep up to the snow, I think my strategy would be to engage 4WD when it was needed, not engage it in the hopes of not needing it. Having said that, I have lockers front and rear, and I have a complete other set of issues relative to my lockers to worry about when driving on icy roads.

Eric:

It's the turn on dry pavement that is the problem. The drivetrain will bind up almost instantly during a turn. The sharper the turn, the quicker and harder the drivetrain will bind up. Turns on dry pavement while in 4WD are a definite NO NO.

Tom

snip

I will definitely avoid this in the future. Could I have done any permanent damage?!? It seems to work just fine when I'm not doing anything stupid like turning onto dry pavement...

On 06 Jan 2004 05:23 PM, Eric posted the following:

When I shift from 4hi to 2hi at speed, I usually let off the throttle for a brief instant right after shifting the lever. This unloads the drivetrain and allows the transfer case to disengage easier.

---------------------------------------------------- Del Rawlins- del@_kills_spammers_rawlinsbrothers.org Remove _kills_spammers_ to reply via email. Unofficial Bearhawk FAQ website:

Same here; I not only let off the throttle, but I go ahead and put the clutch in so I make sure there is absolutely no input from the engine/tranny side of the t-case. In the case of turning a corner from a slushy road onto a dry main road, I will usually use 4wd, 1st gear to get going, and then put the clutch in, shift to second, AND pop it into two wheel, if the road is dry, right before begin turning the wheel to aim down the main road. No binding occurs, but I get to take advantage of the 4wheel to easily start from the light.

Probably not. The chain has to stretch quite a bit before it causes a problem. You described EXACTLY what happens when the tcase is bound up. Now you know why it binds, and what to do to avoid this.

Normal. Remember... Going into 4wd, Gas on while shifting, ease off. To go back to 2wd, gas on while shifting, ease off. Your clunk will go away if you do the shift right. Leave your hand on the lever and you can feel it shift out as you let off the gas.

However, if you drive for a while on pavement, you will still get the clunk sometimes due to drivetrain wind up.