A couple of weeks ago, the 4runner started making a clicking noise when under load (in the gas). The click increases in speed with road speed. Doesn't matter what gear or RPM range I'm in. Flat, uphill or downhill do not seem to matter. It goes away when coasting, and is a real pain to try and diagnose. Anyone experienced anything like this before?

 

u-joint maybe?

 

I've checked the u-joints, they seem okay. Upon closer inspection, it looks like the rear Pinion Drive in the 3rd member may be bent.

 

if its in the motor prolly just a lifter, doubt if its a rod

 

Put the truck up on stands, and it is coming from the rear end. Looks like 3rd member rebuilds are in the not too distant future.

 

if your pinion is bent you should also get a vibration when rolling at speed. i would say take your rear end apart and inspect the gears and splines to be sure your not causing more damage driving. are your rear tires matching? if you have different size tires left to right you may be stressing the spider gears a bit more which will fatigue the 3rd.

 

unbolt the shaft and feel the joints for stickyness might be stiff joint would be alot easier to fix, have you tryied to lube them and see if noise changes?

 

Didn't notice that response ^ till after the fact.


I just went through the same thing with my truck. Had a clicking noise mainly under heavy acceleration. Turned out to be a bad U-Joint. Fitgured this out after I pulled the rear end completly apart. Unbolt the drive shaft and really check the U-Joints before you go any further. The bearings may be messed up.

 

Not getting any vibration at speed which is what has be baffled. I had the rear end apart not too long ago, and it still looks brand new. Rear tires are matched, BFG All Terrain 33's. The noise started a couple of weeks ago, and I had not made any changes that would result in the noise.

I will replace the u-joints first, just to be sure. I have not been driving the truck except when absolutely necessary, which now shouldn't happen at all as I got my other car back up and running.

I think the new definition of insanity should be to try to have 2 mid 80's vehicles and try to keep them both on the road.

Thank you for the input, the journey continues. I'll have to get new u-joints, and if that doesn't fix it, it hasn't hurt anything.

Thanks for the input.

 

Before you buy new joints, pull the driveshaft and check them out.

 

I have, sorry, I missed your above post. They have no play in them, but do appear to be a bit stiff. Greasing them didn't seem to help.

 

well if they are stiff then is a good bet replaceing them, they should move very smoothly considering they are used. just so you know.

 

Well, I finally got it pulled apart, and think I found the culprit. Unless the Pinion gear is supposed to look like that, which I doubt.

Time to ship the diffs off to JT I'm afraid.

Click for bigger picture:

 

Thats supposed to be that way. That allows additional oil to the bearings to prevent broken teeth on the pinion gear...


Oh.... Maybe yours didnt have ENOUGH broken teeth....

 

I feel your pain. A few months ago while I was pulling a tractor up a steep gravel hill in My 2500, I heared a load pop at the top where I turned to the right.. I thought it was the hitch ball popping inside the reciever. Nope.. then I found out it was a GM posi I broke. Spider gear tore all to pieces by the time I made it home. Bummer