Hey all,

I've got a thunk going on in my 88 4runner (22re, 5 speed) and I'm hoping for some advice on how to proceed.

It happens at the initial load, just as I engage the clutch and start moving. It happens in 1st, 2nd, reverse, and maybe a tiny bit in third. I can drive gently so that it doesn't happen in any gear.

I am fairly certain it happening in the rear axle and not the transmission, and I can't feel it through the stick shift if that makes sense. It is a fairly deep sound.

I noticed today driving around in 4 wheel drive in our snowstorm that it absolutely does not happen when 4 wheel drive is engaged. Still happens if hubs are locked and driving in 2 wheel. Strangely, the transmission seems to shift better when I'm in four as well - in two wheel drive first and second can be hard to get into but not in 4.

So far I've checked the suspension bolts, all are tight. Driveshaft bolts are tight as well, and I don't seem to have any vertical or side to side play in the shaft. If I try to rotate it by hand it moves maybe 1/4 inch either way but I understand this is normal driveline lash. PO said he had the u joints done - do I have to remove the driveshaft to check for play in those? There was nothing noticeable when trying to rotate the driveshaft.

I have a feeling I'm looking at a differential problem.


Thoughts?


Thanks in advance for any advice,

ANDY

 

try changing the u joints and check your ring and pinion and make sure it has all its teeth

 

Trust me, drop your driveshaft and play around with all the ujoints. I had this werid clicnking noise/squeaking noise that i couldnt find out. Sure enough my ujoint was shot.

 

Cool that sounds like the easiest way to begin... I would like to not take apart the diff if possible at this point.

 

and to add confusion-
if the springs are fatigued, you could be winding up the rear axle enough to cause the overload leafs (a.k.a. surfboards) to thunk against the other leafs.

 

That is true to, i'd start with the ujoints. I couldnt belive all my noises went away when i swapped in my spare dshaft lol

 

leaf springs seem good - plenty of arch in them. I had a truck before that had some nasty windup and it doesn't really feel like that at all... but I'm not ruling anything out. dshaft off as soon as the weather gets nice!

 

Sounds good, keep us posted

 

Pump those u-joints full of grease and see what happens...

 

Lack of grease could cause this sort of thing?? ...well... I'm sure it could be the source of messed up u-joints but could grease be the cure here?

 

thesound may be the DL.

check the u-joint for play and pump the DL and the UJ full of grease. refer to service manual on grease points if unsure. If that doesnt do it then let us know.

i could just be play and when it takes up the slack (play) suddenly it makes the sound that worries you.

I had the same sound and after a year of me wondering what the hell it was the DL flew off LOL

 

Sorry but DL? not sure what you mean...

 

DL= driveline

UJ= U joint

Basically look for all the zerks under your truck...and zerks are the fittings that the grease gun goes on...theres alot of 'em, so thoroughly check

 

X2 grease er up and report back

 

Just drop the driveshaft and grease them up, then move the joint around and regrease just to make sure everything is filled.

 

Sorry for the resurrection but I finally solved this problem. After going through and replacing a third member (needed to happen - play in the pinion) and replacing all my u-joints the problem slightly lessened but never went away. I was scared it was something expensive too... if I tried I could make some seriously loud, metallic clunking noises, especially under initial load in reverse. Also, going over bumps would cause this noise as well.

So, the problem was the tranny mount. I put a trail-gear heavy duty mount in there and I'm noise free. err, well I would be if this thing didn't transmit engine vibration straight into the frame. but i knew that going in.

FWIW my mount looked great - no cracks in the rubber or anything, but my shifter just seemed to move more than it should.