"thunk" sound when engaging 4WD.

[atomic punk]

I have had the 4R for exatly 1 year now, and have probably used the 4WD only a dozen times or so.

Last weekend, while going no more than 5mph while turning and pulling out of a gas station, I engaged the 4WDhi and heard a "thunk" sound from the area of the tranny. It wasn't LOUD to the point of being unbearable, but it was certainly noticable. I thought it was weird because I have never heard it before. It drove fine. Took it out of 4WD fine.

Then today on the way to work, going about 20mph, I engaged it and heard the same thing.

Is this normal and I just haven't ever heard it before (maybe because I have had the radio up too loud) ????

 

[srpage]

You mentioned turning while going into 4 wheel drive. You are supposed to shift into 4 wheel drive while going straight. If you shift while turning you will get sone pretty good clunking and thumping.

I suspect if you shift while turning, the speed differential from the front axle compared to the rear causes the Torsen transfer case differential some difficulty.

 

[Northof49]

It's normal. The noise will be louder if you're turning, on a less slippery surface, acceleration, or any combination thereof

If you are on dirt or snow going straight, you may here no noise at all. If you're on dry pavement, turning, with you're foot on the gas, it can be quite noticeable.

 

[atomic punk]

K, thanks..... good to know.

 

[Fro-Runner]

Yep.....very normal. If you want to hear a bigger thump; engage the vehicle in 4WD LO but do NOT drive it on dry pavement. I engage my 4WD HI and drive for about a week every 3 mos. Every six months "while sitting still"---I also engage 4WD LO so the system's electronics will stay lubricated. I will only drive the vehicle forward enough to allow full engagement of 4-LO.

Be SURE that your wheels are straight when you shift into 4LO and make DANG sure you are out of 4LO before getting up to driving speed limits. You may have to drive the truck forward or backward several feet to get 4LO to engage and disengage properly. Everyone needs to engage the 4-LO tranny every 3-6 mos. even though many here will NEVER use it.