Need help diagnosing clunk when in multi mode 4wd

[OrRunner]

My 2002 t4r v6 has developed a clunk when using the multimode 4wd. The clunk can be reproduced when sitting still by shifting from park to reverse and back (will occur in both directions) or when coasting then getting back on the throttle quickly while driving. Does not occur if the throttle is applied smoothly. I’m guessing motor mount, trans mount, or front diff mount but I’m hoping to get some guidance on where to start looking. The problem does not occur in 2wd at all.

 

[jgue467]

Certainly check the various mounts. Another quick check that I found was the problem causing a rattling at idle in gear for me was the transfer case dampner.

It's located just behind the TC, that odd shaped item with 2 bolts holding it in place. Mine was loose, s/b at about 28 ft/lbs. Luck. :cowboy:

 

[Riceye]

Are your front and rear driveshafts well greased, esp. the slip joints? Could be a very simple, cheap fix.

 

[OrRunner]

Certainly check the various mounts. Another quick check that I found was the problem causing a rattling at idle in gear for me was the transfer case dampner.

It's located just behind the TC, that odd shaped item with 2 bolts holding it in place. Mine was loose, s/b at about 28 ft/lbs. Luck. :cowboy:

I’ll check it, but I don’t think that’s it. This is a clunk that can be felt in the steering wheel and body of the vehicle. Sounds and feels like it’s coming from beneath in the trans/tcase area.

As far as it goes, i know the piece you’re talking about and my rubber part on it is cracked. I checked what a replacement would be from Toyota and they’re around $400

 

[OrRunner]

Are your front and rear driveshafts well greased, esp. the slip joints? Could be a very simple, cheap fix.

I’ve greased front and rear with moly grease and removed cleaned and lubed the rear slip yoke. I actually still have have a very slight clunk from the rear slip yoke so I may end up redoing that using the ford slip yoke grease recommended by mbtim. I though about doing the front when I did the rear but I couldn’t find anyone who had had a binding problem for the front slip yoke so I didn’t bother. In any case, this feels more like slack in the driveline which wouldn’t be caused by slip yoke binding I don’t think. My first thought was that a u joint on the front driveshaft was going out, but I couldn’t get any movement out of it.

 

[jgue467]

...
my rubber part on it is cracked. I checked what a replacement would be from Toyota and they’re around $400

Forgot to mention, some on here simply remove the 'silly' dampner and don't complain of any ill effects. Yet you're right, it was just a sound not a vibration coming thru the steering wheel and body - that sounds more serious.

 

[nissanh]

This is the famous clunk all the 100 series landcruiser with IFS have. It is mostly the front diff mounts. I replaced all front diff mounts on my landcruiser and the clunk is nearly gone. Google Landcruiser front diff bushing clunk

 

[phattyduck]

This is the famous clunk all the 100 series landcruiser with IFS have. It is mostly the front diff mounts. I replaced all front diff mounts on my landcruiser and the clunk is nearly gone. Google Landcruiser front diff bushing clunk

If it is the diff mounts (they can go bad from oil leaks), Plastics Guy on here makes replacement bushings. Otherwise, you have to buy the whole arm from Toyota...

-Charlie

 

[nissanh]

^^^
For 100 series LC: I was able to buy OEM front diff bushing mount and the stopper that goes above the bushing. There are also 2 other arms on the front diff, and toyota sells those arms with bushings attached and each is about $110 from Camelback, I however found FEBEST (a German bushing company located in FL) makes those bushings and was like $15 a piece shipped on eBay. I and most cruiser owners went that way.