Help! 4Runner with loud vibration

[rossmkh]

Hey everyone, so I've got a 1997 4cyl manual transmission Runner with around 180k miles on it.

Recently my truck has started vibrating. Speed doesn't seem to matter, but it's worse in 3rd-5th and especially when I'm on the interstate. The vibrating starts when I take my foot off the gas to coast while the car is still in gear. If I switch it into neutral to coast, the vibrating stops (so I know it doesn't have to do with wheels/tires etc). The vibrating doesn't happen with acceleration. Any ideas what might be causing it?

Hope it's nothing super serious/expensive. Currently in veterinary school and living off school loans for the next few years :violin:

 

[Konkordmusk]

Sounds like the driveshaft to me. Check, and grease the u-joints. Start there, it probably needs to be done anyways.

 

[rossmkh]

Ok thanks! I'll look into that.

 

[4RunnerChaos]

Hey I have this same problem and posted a thread a while back and most everyone pointed at the drive shaft. I have not gotten down to solving the problem but if u may suggest, get it fixed because it only gets worse lol.

 

[MStudt]

First off, where are you feeling the vibrations? In the steering wheel, or in the seat? If you feel it in the steering wheel it's most likely something in the front. If you feel it in the seat than it's most likely something in the rear. I doubt it's the driveshaft either.

 

[TheeMikeB]

Transmission or motor mounts?

 

[I_bRAD]

I doubt it's the driveshaft either.

Why don't you think it could be the driveshaft? I had similar symptoms when my ujoint was going.

 

[Raintrees]

Why don't you think it could be the driveshaft? I had similar symptoms when my ujoint was going.

well the vibrations stops when the car still moving out of gear, but your drive shaft is still spinning so you would still get vibrations.

 

[I_bRAD]

well the vibrations stops when the car still moving out of gear, but your drive shaft is still spinning so you would still get vibrations.

Yeah, that threw me for a bit too when I had the problem, but in neutral (or depressing the clutch in my case) it greatly reduces the load on the shaft and mitigates the vibration.

 

[Raintrees]

Yeah, that threw me for a bit too when I had the problem, but in neutral (or depressing the clutch in my case) it greatly reduces the load on the shaft and mitigates the vibration.

if it was the driveshaft wouldn't he also get vibrations when he accelerates?
I also like to know were he feeling the vibration at in the truck.

 

[MStudt]

if it was the driveshaft wouldn't he also get vibrations when he accelerates?
I also like to know were he feeling the vibration at in the truck.

If the driveshaft u-joint is bad you'll feel it all the time. Not just when under load from the transmission. Also the driveshaft is going to be something that you feel, and shouldn't be causing a "loud" vibration like the title states.

There's something else going on here in my opinion. I also asked where he was feeling the vibration. That alone will help pinpoint the area it's coming from. The problem with vibrations coming from the underside of the vehicle is it travels. The vibrations and sound can resonate through the frame making someone think it's coming from one area when it's actually coming from another.

 

[I_bRAD]

If the driveshaft u-joint is bad you'll feel it all the time. Not just when under load from the transmission. Also the driveshaft is going to be something that you feel, and shouldn't be causing a "loud" vibration like the title states.

It gets worse when it's loaded though. If it's just starting to go perhaps it's only bad when it's under load?

I know when mine went it slowly started to get a bit worse, but not too annoying- Until I hooked it up to a camper and took it on the highway, and then all hell broke loose. (fortunately the drive shaft did not!)

Not saying it's not something else, but the symptoms of the OP sound very similar to what I experienced with a bad u joint.

 

[MStudt]

It gets worse when it's loaded though. If it's just starting to go perhaps it's only bad when it's under load?

I know when mine went it slowly started to get a bit worse, but not too annoying- Until I hooked it up to a camper and took it on the highway, and then all hell broke loose. (fortunately the drive shaft did not!)

Not saying it's not something else, but the symptoms of the OP sound very similar to what I experienced with a bad u joint.

Quick way to check would be to pack it full of grease to see if that helps. If it helps then the u-joint is the culprit. There are still a lot of things that get worse when under load.

 

[I_bRAD]

Quick way to check would be to pack it full of grease to see if that helps. If it helps then the u-joint is the culprit. There are still a lot of things that get worse when under load.

Yep. You could check the ujoint in less time than it would take to read through this thread!

 

[jeremyc74]

I would get a good look at the motor and transmission mounts. It sounds to me like something's shifting around and either causing the driveshaft angle to change, or allowing something to rub.

Or it could be something that's too close to the driveshaft (heat shield or exhaust hanger) and that's causing it. If you get under the truck and poke around something will probably have some marks on it.

One other thing I can think of is the engine separating from the bell housing. Has the clutch been replaced recently? I had this happen to an old Jeep at one point and it would only make noise when I was coasting in gear because it was only the bolts on one side. When you were accelerating the force would keep them mashed together, and then when you started coasting it would separate. It was allowing the teeth on the starter ring to get against the metal dust shield and made a hell of a racket.

Do you have a GoPro? If so, mount it under there and go for a drive. Something will show itself.

 

[rossmkh]

If the driveshaft u-joint is bad you'll feel it all the time. Not just when under load from the transmission. Also the driveshaft is going to be something that you feel, and shouldn't be causing a "loud" vibration like the title states.

There's something else going on here in my opinion. I also asked where he was feeling the vibration. That alone will help pinpoint the area it's coming from. The problem with vibrations coming from the underside of the vehicle is it travels. The vibrations and sound can resonate through the frame making someone think it's coming from one area when it's actually coming from another.

Thanks for your help everyone! No the clutch has not been replaced recently (as long as I've owned it starting around 130k). The vibrations are definitely coming from under the seat it seems like, definitely not the steering wheel.

 

[4RunnerChaos]

Thanks for your help everyone! No the clutch has not been replaced recently (as long as I've owned it starting around 130k). The vibrations are definitely coming from under the seat it seems like, definitely not the steering wheel.

Well if its any consolation I pulled my driveshaft (about 30 minutes work with hand tools) $17 U-Joint $40 labor and now its sitting in my garage to be put back on tomorrow.

When. This problem first arose I could NOT get any strange movement, and even after three of the bearings almost completely decintegrated could I get any weird movement using my hands while still attached.

Go under there with a 14mm wrech and 14mm socket on a breaker bar and ratchet with a 3 inch extension and drop the shaft, won't take too long.

As for sound and feel of the problem, even after nearly completely destroying the U-Joint I only got a vibration from 30 + mph, and would fade under deceleration below 65ish mph and would only come back after putting a load back on the drive train. And for feeling it under the seat, it makes sense because the resonance from the shaft will translate mostly through solid connections ex driveshaft to transfer case to transmission to crossmember to frame to body. And axle to control arms to frame to body. Crossmember is under front seat and control arms are under the back seat. And vibrations coming from the back will be drowned out by what's directly under you. And anyways it would be traveling through shocks and spri gs, which kinda absorb those vibes.

Take the time to drop and get a good inspection of the U-Joints and replace the one you need to replace.