Front End Clunk When Going from Rev To Fwd in 4x4

[Axemonkey]

I have searched here for an answer, not finding anything quite like what I am experiencing.. maybe I missed it.

Anyways.. this problem started a year and a half ago or so.. I got stuck and was rocking the truck in Fwd to Reverse, and it started clunking after I would shift directions. Now the problem is more frequent when in 4x4.. if I go from Fwd to Rev, or vice versa there is a clunking noise that seems to come from the front drivers side. I've been told its likely the CV joint.. 4x4 works fantastic when I'm just driving in either direction.. no noises regardless of speed or if Im turning the wheel.

Anybody? I need to get this fixed ASAP!

Thanks!
Rob

 

[92exp4x4]

I assume your truck has the auto hubs? Those are the weak link in the front end. There is a plastic cam and other components inside it that don't like alot of excessive grease, or force put to them. Do a search on the auto hubs, there are lots of threads on here for them.

It is normal for the auto hubs to click when changing direction. They actually unlock and relock when the axle shaft changes direction. Thats how rocking can damage them. Manual hubs are the solution. They are positivly locked always while engaged and do not unlock while changing direction. Only drawback is you have to get out and manually lock and unlock them to isolate the front axle.

Other things your noise could be are:

U-joints in the front axles or drivshaft, front units frequently rust up from non-use.
Ball joints or steering ends

Make sure these are in good condition as well.

 

[Axemonkey]

The sound that is coming from my front end when I change direction in 4x4 is not normal. It is a very distinctive CLUNK (exactly the same as the clunk when you push the button to engage 4x4 when you're in motion) I've had the truck for 3 years now, and this noise and the frequency of it is fairly new. I'm guessing I may have done some damage to the drivers side when I was rocking it as I mentioned in my post. Ball joints are almost new and all other parts you mentioned are in great condition.. I figured either a CV joint of some kind as was suggested to me.. or there is something wrong with the drivers side auto hub.

 

[Axemonkey]

Actually it just seems like the drivers side is a little slow to re-engage when you change direction.. engaging just a little after the passenger side. Is it possible it just needs a cleaning? Really, it seems to do its job and it doesnt make any of the classic sounds a worn hub would. Once its engaged, it works perfectly driving straight or around corners.. it just has some weirdness when you change directions...

 

[92exp4x4]

It could be sticking and slow to engage like you say. Some people clean the excessive grease out of them with trans fluid or even kerosene and they say it helps. I have only one Ex with auto hubs and I have never had problems with them. The others are either 2WD or have Warn manuals.

I would try cleaning them and see what happens. That grease can get sticky in the cold weather. Let us know what you find.

 

[Axemonkey]

Thanks

Thanks for your suggestions! I will give that side a cleaning and see what happens.. I suspect that may very well be the problem. Yesterday when it was real slow to respond I had been driving in -20C for about 200 miles. Today it has warmed up and it is responding faster.

I will post the solution when I figure out what is wrong. I'm on holidays right now but I will have it looked at when I get home on the 5th or 6th. Leaning towards cold sand dirty/overgreased ATM...

 

[RangerX]

I would inspect your radius arm bushings, especially the passenger side one. If it's worn out or rotted away, it would cause a nice clunk from the freeplay when changing directions.

 

[Axemonkey]

Nope..

Radius arm bushings replaced this year.. different noise altogether. This is definitely related to the front drive assembly.. strongest suspicions either a damaged or dirty/frozen hub.

Thanks anyways.

 

[92exp4x4]

I thought that too, my 92 needs RA bushings. But you were very insistent the noise is from the wheel end.

 

[Axemonkey]

I'm 100% positive it is related to the drive assembly. Whether it is U joint, CV joint, Drive shaft, hub. You can see and feel the wheel spin when it clunks and the drive engages on the driver side. Anyways as I say I'm fairly sure it is either a damaged or dirty/frozen hub. Thanks anyways.

 

[KPSquared]

While were on the subject of clunks, I've got the same thing going on.

Tonight was the first time out after the rebuild.

New lift (superlift 5.5") new pivot bushings, new RA bushings, new ball joints, new pads and rotors, new Warn Jeep hubs and fresh installed 4.88 gears.

When I switch from forward to reverse in 4x4 it clunks or almost like a bang. Can feel it through the floor board. NOt sure where to start. Just had the drive shaft out today and all the joints feel good. Can something bind in a brand new manual hub and cause the clunk?

 

[Anime]

The sound that is coming from my front end when I change direction in 4x4 is not normal. It is a very distinctive CLUNK (exactly the same as the clunk when you push the button to engage 4x4 when you're in motion) I've had the truck for 3 years now, and this noise and the frequency of it is fairly new.

When engaging the 4x4 at speed, or changing directions, my X has always made a very loud CLUNK from the drivetrain. This is usually a sign that everything is working fantastic and the hubs are locked in and the wheels are turning.

AFAIK the only way to not get a clunk is engaging the 4x4 when not moving, then accelerating VERY slowly, and doing your direction changes very, very gently so the hubs simply click to disengage and re-engage in the opposite direction.

The only quiet TTB front ends I've heard were ones that had bad hubs and didn't engage. Almost every TTB is rather loud and clunky sounding when it's working properly.

That said, a bad u-joint might cause more noise than normal, since when the sealed joints go, it's usually from being dried out and instead of a smooth, lubricated pivot, it's being made to twist and turn in a dry, rusty socket with needle bearings that are broken or reduced to rust. It's not a bad idea to replace all the U-joints (good quality Spicer replacements are great, part number 5-760X) whenever you've got the front end apart or the front shafts out.

 

[Axemonkey]

Nope...

This was an abnormal sound. Mine normally makes the clunk you are speaking of this was way out of the ordinary. It turned out to be a bad wheel bearing of all things after having everything checked out.

Thanks all for your input.