So I'm moving along in 4WD and I get a massive "clunk" (feels like a slip followed by a slam). The truck then keeps on trucking in 4WD like nothing is wrong....until another clunk.

In 2WD...truck runs fine. I never feel this "clunk" or "slippage".

Any thoughts on what might be going on?

This is going to be my hunting and wood-getting truck. So I need 4WD to work properly.

 

Does the clunk feel like it is coming from the middle or the front of the truck?

 

It felt like the front. I mean, I fully expected to look behind me and see something on the ground...it was that loud and jarring.

But yeah, to answer your question...I'd say mor like the front.

 

Quote:

Originally Posted by ID1982F150I6

But yeah, to answer your question...I'd say mor like the front.

Have you looked at/inspected your front axle & driveshaft U-joints? Next thing to
come to mind is a front hub but I've never experienced a failure in one myself so
can't equate those symptoms. Finally, there's the transfer case (athough that's
more in the middle of the truck, its forces are transferred to the front).

 

Tire sizes, gear ratios same front and rear.

-Enjoy
fh : )_~

 

Yes, are you running on dry pavement when this happens? If your tire sizes are not close, it will build up stress in the driveline till it suddenly releases it. One of those times it might break something.

Drive on a gravel road in 4wd and see if it goes away.

 

Yeah, you know...i didn't even look at the tires to make sure they were EXCACT. Thanks for the suggestion.

Yes, this was on dry pavement...which I normally would not have the truck in 4WD during. However, I was towing my other car from a wet muddy field...yada yada yada...then onto the dry pavement and I didn't want to stop.

While I have your attention, do you have any advice on a Suspension Lift Kit Size? I don't want to run into alignment issues. I was thinking the 4" suspension from Rough Country.

Also...it looks like I need to replace the exhaust on this thing. If you have suggestions there on what to replace with, I'd like to hear them.

Thanks

 

Did another test today.

Hubs engaged + 2WD = No large jarring force.

Hubs engated + 4WD = Repeat of large jarring force. (also, this seems to occur with 2 "jarrs" at a time).

I had a buddy ride with me today, that is more mechanically inclined that me. He seemed to think it might be the chain slipping in the transfer case.

 

Keep running it in 4wd on dry pavement and pretty soon you will be asking how to replace a transfer case.

 

This isn't normal. I don't think it has much to do with driving it on dry pavement or not. It did the same thing down a gravel / dirt road.

Also...I live at 6300 feet, in the mountains of Idaho. I can't be worried about whether I'm in 4WD for 1/4 mile on dry pavement between sections of compact snow and ice.

Anyhow, if anyone has seen this problem before, let me know. It looks like I'm getting into a Transfer Case overhaul at this point.

 

looks like you got it isolated to the t-case. with same size tires and rather straight shots pavement should be too bad. I run with my hubs locked in and in 2wd. I shift into 4 wd when needed.

 

Did you just buy this truck? I wonder what the gear ratios are front and rear? Even if the chain was wore out in the transfer case, I don't see driving it down the road in 4wd putting any strain on the system at all, unless the front is not working with the rear. Theoretically the front wheels should be turning the driveshaft and the transfer case, and there is no pull on the transfer case parts.

On my old 80 I stripped the splines on the slip joint going over to the passenger side front wheel. I knew it was wore out, and all it took was me getting hung up in a big snowfall to strip it. I could not work on it right away, but driving along in 4wd you could not tell anything was wrong. You could only hear it grinding and slipping when the going got tough and I need the front wheels to pull.

 

Yeah...the '82 F150 is a new truck for me. I really just bought it for getting back and forth to work, getting wood, and hunting. Plus I thought it might be kinda fun to work on and learn a few things along the way.

I got tired of beating the heck out of my '05 F250 Diesel.

 

I would jack the rear up and measure all the way around one of the tires, and also count how many turns the driveshaft makes when the wheel is turned one turn. I would then do the same on the front and see if everything matches.