loud clunk on hard acceleration

[smokey73]

I have and '03 V8 limited 4x4 w/240k on it. I've noticed that on a hard acceleration from a dead stop or a slow roll, you can hear and feel a hard clunk from the rear end. It sounds like its suspension related at the rear end itself. I also hear a different noise when you accelerate while turning, this one is more of a rapid clicking coming from the t-case. Any thoughts on either one?

 

[CXS]

Check your drive shaft u-joints for slop, it may be that simple and account for both noises.

 

[smokey73]

I hope it is something as simple as that, but it sure sounds expensive

 

[CXS]

That's not too bad though brace yourself for some that are!

 

[smokey73]

Well... I checked the drive shafts, front and rear, and didn't see anything bad. I did found that one of the rear upper lateral link bushings was toasted causing the clunking in the rear end. No big deal I'll get to that when I've got it in the air doing the lift. I also found the left CV shaft had a ton of slop in it and the inside boot was torn in half. I went ahead and replaced the CV shaft ($70 Rockauto and about 10 minutes of work). The shaft came out in two pieces, I'm not sure if it was supposed to, but I thought that was gonna solve it. The popping is still there. Its loud and sounds pretty bad. I think its getting worse. It does it anytime you accelerate hard, in a straight line or turning, from a stop or while going down the road, 4hi or 4lo. I'm thinking its in the front axle or the t-case. I'm gonna pull the drive shafts on at a time and see if it changes anything. Has anyone dealt with anything like this.

 

[Velonici]

Have you greased the slip joint lately?

 

[smokey73]

I haven't, nor do they appear to have been greased at anytime in the last 200,000 miles. I pulled the front shaft and drove it around, I had to lock the center diff in to get it to move. I thought that the torsen would split the output when there was slippage and would go ahead and pull with the rear, but it wouldn't until I locked it in. I suspect the t-case is the issue

 

[Velonici]

I haven't, nor do they appear to have been greased at anytime in the last 200,000 miles. I pulled the front shaft and drove it around, I had to lock the center diff in to get it to move. I thought that the torsen would split the output when there was slippage and would go ahead and pull with the rear, but it wouldn't until I locked it in. I suspect the t-case is the issue

Thats the way it works. Without the front hooked up it will just spin. I had that issue when an axle split on me. I would grease up the slip joints and see how that helps. Here is a good write up on the process.
http://www.toyota-4runner.org/maintenance-detailing/28414-07-v8-4x4-zerk-fitting-pics.html

 

[smokey73]

I hooked everything back up and greased both shafts. If you shift it to 4lo and throttle into it, the engine revs like it's in neutral and then it catches and goes into lo. I've found that if you put it in 4lo and hold the brakes it will pop and bang without moving. The sound is coming from the t-case. If i do it hard enough while sitting, the 4lo light will go off and it will stay in 4lo. I believe it either the actuator or the shift forks not engaging or popping out....bummer...

 

[Velonici]

Are you putting it into neutral when you shift between 4hi and 4lo? You should be stopped and in neutral. The only thing you can turn off and on while moving is the center diff lock. But you cant turn on hard surfaces with it locked. It can take a second or 2 to go between the 2 modes. Some times if the gears arent quite lined up you might have to put it back into drive and move a couple of inches back or forward.

 

[smokey73]

just for future reference, the original clunking I heard, that I assumed was the rear lateral link bushings (because they were nearly gone on the upper right side) was really the transfer case. I found that the t-case had no oil in it. After tearing it apart and deciding to replace the whole thing, both noises were gone. The clunking that sounded like it came from the rear end was only heard if you were sitting still or just creeping and hammered down on the accelerator, it would make one clunk and that's it. I believe that it was from all the slack that was in the chain inside the case. The other noise was a rapid clicking and later a loud popping coming from the t-case. It started out that you could only hear it when accelerating hard and quickly got so bad that you couldn't drive anywhere with out it making noise. I only owned this thing a week before finding out the case had no oil and had to replace it. ($900 for a junkyard special)