Ok here's one for ya..
Have a 95' with a 3.slow.
I get a vibrating noise..almost sounds like driving over those ridges in the center divide (Wake up strip).

I am at about 68 mph or so and it occurs when I let up on gas..I goose it it goes away comes back for sec then goose it again then it goes No problem ...I think. I can't figure it out??! I thought it was soem pulley or Idler for Timing belt.?? No friggin clue.

Happens after warmed up. I do get some odd noise when still cold sounds like belt rub..? not sure..

Ok, thoughts anybody..??
Thanks
Tom G
Placerville

 

if the strips are like those on the sides of the road as well...the little lumps.... that reminds me a bit of the sound a tire might make rubbing on something. have big tires? maybe when you let off the gas...the weight shift makes something rub.....

thats all i got. it came to mind so i thought it might help.

 

Possible driveline problem. Underload play in your joints or bearings might not show up... coasting or no load vibrations might be felt like you describe.

Get under the truck and see if anything is obvious, wrench on driveshaft to see what moves, check for play if rear diff as well.

 

Ya I kinda thought of that but the sound is like running a stick over plastic ridges... not metalic leat that i can figure.
I recently added OME 901s to the back and put in the aisin hubs. I'm going to tweak the torsions a touch to level out the front shortly.

Anyhow the trip is that its so intermitant only does it once in a long drive so far. But I will look over the drive line.
My first thought was #1 or 2# timing belt idler going...?
But makes no sense really. My other thought was tranny.
I do need to flush tranny haven't done that in a year at least..

Thanks for the feedback.

 

Wonder if it could be your radiator fan hitting something? Maybe a hose shifts with engine torque or air movement at higher speeds.

Check for loose hoses, wire, tape, whatever around the fan. Maybe the shroud is even cracked or loose. Maybe fan clutch is on it's way out and is causing the fan to run out of true and tick on something.

Sure would be nice if it was something that simple.

 

Well I changed the diff oil (89/140..didn;t look at what I was buying but shouldn't harm it) and checked for anything rattling or loose as well as fan clutch etc. but nothing and no change. The diff seemd alittle bit warm but I think thats normal. (Not searing my flesh...)

Still this happens at 70 coasting. Actually it seems to build from 60 on. I checked my tires as well but this is not a 'soft' sound. I am still at a loss... very vexing problem. Everything seems ok around town and when I am wheel.

I guess I have to wait tills something doen blows up...

thanks for the suggestions
Tom G

 

Upon further investigation, I have narrowed it down to perhaps a pinion bearing. With the new angle onthe driveline it added stress to it so far as I can figure.
Thanks again for the help.

 

Have you verified it's not the A/C idler pulley? Bearings in the alternator? What about the universal joints?

 

well i dont know about the 6cyl but i know that 4cyl trucks have to run a little higher RPM's because of lower gearing (and i've heard also because 55mph speed limits were more common a while back...but your truck isnt that old probably)

either way....have you experimented with the same RPM in lower gears? cause if it doesnt make the noise at high RPM in low gear i would think it is in the drivetrain like you thought.

good luck. have a passenger try and listen too....POV (or point of listen...lol) might make a difference and maybe they can learn more because they aren't watching the road

you dont have 4wd engaged do you? i would worry about forgetting that myself... you might check it just incase.

just checking.

maybe you could temporarily reduce your lift? i'm not familiar with the setups and i doubt that it is easy....but i'm all ideas really....i just think about stuff, i dont know....i just suggest.

the reason i thought about it is....in radio control racing/offroading, a quick and easy way to reduce ride height for racing is to strap the suspension up so its already partially compressed.

BUT this is with little coilovers and 1:1 toyotas have torsion bars and i'd worry a bit about whatever you use to compress the suspension breaking while going 70mph and letting your suspension rebound....lol.