Clunking in 4L 4WD??

[jawjatek]

Did a little light trail riding yesterday in my new-to-me FJ60. I noticed when slowly going in 1st gear, in 4L (4WD) drive mode, there is a clunk-clunk coming from up front as the truck slowly rolls and you let off and apply gas. My friend said it sounded like the hub wasn't locked but they both were turned to the correct place. Any idea what this might be?

Did not hear it in 4H mode.

 

[on2it]

does it still clunk if you unlock drive for a bit then lock back into L4? does it always clunk?

 

[Dieseler]

couple of possibilities...your front driveshaft is hitting something if you are lifted you may have bad angle clearance..... or the U joints are binding...or your birfs are toast.

 

[jawjatek]

does it still clunk if you unlock drive for a bit then lock back into L4? does it always clunk?

I'll have to try it again and get back to you; thanks for the tip. Truck has a mild lift in front (back is another story and another thread) and It wasn't bumping on anything.

I was just rolling slow in 1st, not turning or articulating over obstacle or anything. As I would load/unload shaft by pressing and letting off gas slightly I could hear a clunk clunk. I didn't want to stress it further so we switched to 4H mode. We did check the locks but will try that again next time I'm on a dirt road.

 

[dannymontani]

I have the same exact issue. But 4 high as well. Going straight ahead. I am guessing this issue to be a bad pinion bearing or crush sleeve from a PO over tightening. This car is new to me. Working here over for the past year. She's a keeper except this on firggin problem, and with winter heading this way, I would like to repair asap. It snowing as I speek. s***.

 

[cruisermatt]

Does the vehicle jerk when it clunks? I think I have the same problem and would like to know the answer

 

[jawjatek]

Didn't notice any jerking. Still have the issue; just have not gotten around to looking into it further. Hope to acquire a H55F 5-speed tranny and will address the issue when its time to pull it all out.

 

[gregnash]

Had the same issue with my old 4x4 Ford Ranger. Ended up that the internal knuckle bearings and seals were toast on the hubs. If you haven't yet may be time for a knuckle rebuild. Does it not do it in 4H?

 

[hj 60]

My hj60 had the knack knack sound ("faster" sound when driving faster) when making a turn in 4x4 low, some say they can be reversed (but than you have it in 4x4 low in reverse)
And it can snap and break. And if you continue to drive it will also start in 4x4 lo forward, then in turns in 4x4 high , then forward in 4x4 high or even only in 2h rear.

My brother did some fast 4x4 low turns in a remote area and it scared the s*** out of me so replaced both sides but not with oem
o no problems, sound is gone)
It is a cool job, I love it, with the right tools I can deliver the birf in 15 minutes (but to clean all the threads, replace damaged s*** and put a helicoil in the brake caliper the hours fly)

YES! picture time, finally

But first get some grease in there, I have a grease zerc, but anyway here is a picture from the inside, if you squeeze fat in it and it will reach the birf (squeeze, drive, squeeze)

inside were fat will enter:

 

[Randy88FJ62]

Couple of thoughts on your clunking:

1. Slop in front diff - backlash has too much play: Test by putting in 2WD and getting under truck. Move driveshaft back and forth. Do you hear the clunk? Are the gears tight?

2. Driveshaft: Grab front driveshaft in middle at spline slip yoke; does it move back and forth? Are the splines tight? I have this problem with my rear driveshaft at the moment and it needs replacing

3. Remove front driveshaft and engage front hubs. drive at same speed you currently get your problem. Can you still hear it? If you can then it is not the tcase or driveshaft.

4. Put front axle up on jackstands. Make sure back wheels are chocked and hand brake is on for safety. Grab front tires one at a time and wiggle up and down. Significant play means the axle bearing preload is not set right, the turnion bearings (top and bottom of knuckle) are worn, or the axle bearings themselves are worn.

5. While front is up on jackstands, Engage hubs and spin one wheel. Does the other wheel spin? Do you feel and binding? Any clunks?

6. Depending on above tests, drain font diff fluid and look for metal shavings or metal dust. If your drain plug does not have a magnet replace it with one that does.

7. Hubs: Do your hubs "click" when turned from off to locked? There is a spring detent that gives a nice solid click when turned to lock position. If you don't hear that then a hub rebuild is a good idea. Hubs are very easy to reassemble after an axle build incorrectly. If someone did not assemble them properly then you could have partial or no hub clutch to axle shaft spline engagement.

Do all the above and report in. Ask more questions. Once you have rebuilt an axle twice it's veruy easy to visually understand how your system works.