low speed driveline vibration

[WarDamnEagle]

My son was complaining about a noise and vibration in second gear before we put the 4Runner in the paint shop a few weeks ago. I have now driven it a bit and am just starting to try to figure out what the problem is. I don't really hear much of a noise but the BFG MT's are pretty loud so it's hard to tell. I do get quite a bit of steering wheel vibration in first and second. I would say it smooths out somewhere above 30mph. So far the only thing I've checked is the PTO shaft and it seems to be OK, at least as far as having no excessive play. It idles smooth so I don't think it's the motor mounts. I thought I might have overgreased the PTO shaft slide but I pulled that fitting and no grease came out so I don't think it's that either.

The only other things I can think of are perhaps front wheel bearings or the transmission but I'm really just guessing. Any advice appreciated.

 

[KLF]

I assume by "PTO shaft" you mean the driveshafts.

Have you checked the draglink? I think you are still running the stock push-pull steering. There is a funky ball-and-socket joint at both ends of the draglink, with a spring that is supposed to keep the halves of the "socket" tight around the ball. These joints can loosen with time. You have to pull out a long cotter pin, and you need a big honkin' screwdriver to tighten the joint. They actually make a special socket to tightening them (Google for "draglink socket").

Might also be excessive play in the steering box. There is an adjustment on it.

Everything tight at the transfer outputs? No play in the output bearings?

How is the steering damper?

Maybe try a different set of tires & wheels, as a test?

 

[WarDamnEagle]

I assume by "PTO shaft" you mean the driveshafts.

Have you checked the draglink? I think you are still running the stock push-pull steering. There is a funky ball-and-socket joint at both ends of the draglink, with a spring that is supposed to keep the halves of the "socket" tight around the ball. These joints can loosen with time. You have to pull out a long cotter pin, and you need a big honkin' screwdriver to tighten the joint. They actually make a special socket to tightening them (Google for "draglink socket").

Might also be excessive play in the steering box. There is an adjustment on it.

Everything tight at the transfer outputs? No play in the output bearings?

How is the steering damper?

Maybe try a different set of tires & wheels, as a test?

Thanks; those are all good suggestions.

I have a fairly new drop draglink but will check the tightness on the end. Yes, I meant the driveshaft. I tightened the steering box a few years ago but will give that a go as well. OME fairly new steering damper. I am going to have the tires rotated and balanced but I don't think they would produce that much vibration at such a low speed; of course I could be wrong.

 

[WarDamnEagle]

I hate dead end threads so...

Turns out it was the rear yoke on the rear driveshaft. Here's the thread with the details: https://forum.ih8mud.com/79-95-toyota-truck-tech/607005-85-4runner-rear-drive-shaft.html

FWIW, I learned the hard way that you need to take the vehicle out of gear and really play around with a driveshaft to tell whether or not anything is loose.

 

[cruiser88]

Yea I agree and always check somebodys work afterwards.
A short time ago I was under my rig doing my annual grease and etc and noticed something rather puzzling, my trail gear skid plate was completly shifted to the left. Christ I say this cant be good, so I check my rear yolk......s*** the pinion nut loose as hell. Keep in mind I have a spool so extra strain driving on the street.

I tightned the nut, it didnt hold long even though, it didnt leak or make any noise. and another lesson learned is if you are running a Marlin box, dont be a cheap ass, use the extra mount. I was told to and did not.

The guy in 09 I let put the clutch in, didnt center up my plate but in reality that is something I also should have noticed.