the1998sr5

I went off roading today and was backing out of some thick mud when I heard a loud noise and felt a studder or popping. It sounded like it was coming from the front, but sounds can be misleading. I tested this afterwards and found the issue to happen only when I am in reverse and in 4 wheel drive and with load on the driveline. For example, (while in 4wd and reverse) gassing it from a stop (dosent happen unless I gas it generously). At first I thought the sound was of my front driveshaft breaking, but it looks to be ok, and the 4wd is still working. I bought the truck as a dd, but with a strong interest in off roading and I do not want to find myself in a situation where I get stuck on the trail, the noise it makes when this happens sounds nasty. But again, this is only happening under load on the driveline, in 4wd and in reverse.

-I considered that perhaps in heavy load situations the tcase/ or transmission could be moving because of old mounts or worn mounts causing the geometry of the shafts to change and cause this popping/studdering. This is just a theory and I would be happy to hear some thoughts on the subject, if anyone has any ideas.

Stetson_md

If it only happens in reverse and 4wd id check the transfer case then the front axle

Adam F

Your going to have to get under there and check things out for yourself. Could very well be a worn out mount causing things to flop around.

the1998sr5

More info,
the truck has 160k on it.
I bought it used 3 months ago, the guy did not seem mechanically inclined, but said he had it serviced "as necissary"
I have done some searching and seen solutions as simple as lubing the u-joints- to stripped front gears.

I wish i could describe the noise better, but it wasn't a sound I want to intentionally recreate agian due to the fact that it seriously sounds like something is going to break. Id say it was a serious clunk, jerk or pop sensation.

I hope this info helps because I am not getting a ton of responses.

FanaticalKilla

Jack the truck up and put the truck in 4x4 and turn driveshaft (By hand) see if you can feel anything that way.

AppalachianOffRoader

I was just about post this exact same question tonight. If you happen to find out what it is before me, please let me know! Cause you're right, it does sound like something is gonna break

SoCal4Running

Do you have Auto Hubs?

AppalachianOffRoader

No, they're manual hubs.

the1998sr5

I Greased all the fittings on my front and rear u-Joints a lot, especially the slip joints.

After that I popped it in 4wd and tested it in reverse. The thing made the same noise. I then drove to my mechanic and tried to recreate it again, and it has never made the noise again since then.

My optimistic thinking has left me feeling that everything just needed a good greasing, and that first trial afterward was when the grease really worked its way in there.

Please keep me posted, I would be interested to hear how this works out for you.

Good luck.