As the title says, when I shift the dash switch, I get a loud "clunk" when it shifts into 4WD...sometimes two clunks. Doesn't happen coming out of 4WD, nor in 4WD low.

Any ideas as to the problem? 5.4l; 2001.

Jim

 

Can I ask if you would expect different when the Tcase motor runs, turns a shaft internal in the trans and the front actuator pulls the locking sleeve to lock the front axles together?
Said another way, it's normal.
When you don't hear anything, there may be cause for concern.
Mine has always done it and has 223,000 miles on the truck with no 4wd problems so far..
Good luck.

 

Well, it's a pretty substantial "clunk/bang," and truck lurches pretty good.

Jim

 

You will have to check out the operation looking for an issue if it is that bad.
When you request 4H, the case motor runs to first position, turns a shaft internally to engage the case to the transmission and operates an electric clutch to sync the gear that engage at that time.
Then the front Actuator engages the front axle sleeve to lock the front axles.
Good luck.

 

Does anyone have a link to any good information on upkeep of the 4WD system? I was thinking to pick a weekend and take it all apart, clean, lube (where appropriate), etc.. but I'm an IT guy, so having clear instructions is really helpful.