Violent shaking/shuddering when coasting at speed

[BrandonF]

Just recently, my 4runner has developed a horrible shuddering when coasting at higher speeds. It starts at 45mph and by 50mph, it is approaching defeaning. It gets slightly better at higher speeds but it's still very bad. This only happens when coasting. Whether I'm braking, coasting with the engine engaged, out of gear, or with the clutch in (manual trans), it makes no difference. The shuddering and noise is still there. However, as soon as I apply any gas, everything disappears.

Due to this, I'm thinking I should rule out the engine and transmission? My experience tells me it's a drive shaft or wheel bearing issue, but I really have no idea.

Any help would be appreciated.

 

[wake_rider]

Hmmm. Can you feel or hear where you think it's coming from?

Odd that it's resolving the problem under load. Have you tried moving your driveshaft around by hand to check for play?

 

[BrandonF]

Hmmm. Can you feel or hear where you think it's coming from?

Odd that it's resolving the problem under load. Have you tried moving your driveshaft around by hand to check for play?

Thanks for the reply.

I have not tried that yet. I did lube both driveshafts about two weeks ago but I dont see how that could effect anything.

A friend of mine has access to a shop, so Im hoping I can get it on a hoist in the next couple of days and start checking things. Id like to get the wheels free hanging so I can give them a good shake to test for any play.

It's very hard to tell wear the noise is coming from. It's such a deep resonating noise that it sounds like it's coming from everywhere.

When coasting down large hills on the highway, which is where the problem is the worst, the deep resonating shuddering is accompanied by a higher pitched rubbing/whirring noise that to me, sounds like a shot bearing. But again, I cannot say anything for sure.

 

[BrandonF]

BUMP

Does anyone have any insight on this problem?

 

[Sierra946]

Maybe a bad u-joint? If it has play in it or it's shot, might do that while coasting.

 

[nissanh]

You got 4x4?

Completely remove the rear drive shaft from the truck and engage 4x4-hi. Now see what happens at 45 MPH.

I strongly believe it is the rear drive shaft. If so, don't buy cheap U-joints. find a good used TOYOTA drive shaft. I went through the same situation. Installed a U-joint and still it vibrates (but much less) then got a 300K mile driven drive shaft!!! it works perfect! Just check each U-joint for any free play.

 

[BrandonF]

You got 4x4?

Completely remove the rear drive shaft from the truck and engage 4x4-hi. Now see what happens at 45 MPH.

I strongly believe it is the rear drive shaft. If so, don't buy cheap U-joints. find a good used TOYOTA drive shaft. I went through the same situation. Installed a U-joint and still it vibrates (but much less) then got a 300K mile driven drive shaft!!! it works perfect! Just check each U-joint for any free play.

Yes it is a 4x4. Do you have any guidelines for how to check it and what is considered an unacceptable amount of play that will cause vibration?

 

[nevada]

rear end. possibly pinion bearing. or maybe even the pinion nut is loose.(very common)
get it jacked up and turn the rear driveline, watch the pinion yoke, see if it moves in/out as you turn the Dline back and forth.

 

[BrandonF]

rear end. possibly pinion bearing. or maybe even the pinion nut is loose.(very common)
get it jacked up and turn the rear driveline, watch the pinion yoke, see if it moves in/out as you turn the Dline back and forth.

I will check that. Thanks for the input.

 

[Appntr]

My guess is rear driveshaft U Joint at the axle end. Fairly common for everything youre talking about it doing. When under load, the u-joint binds up in a sense keeping anything from vibrating. But as soon as you coast there is no torque on the driveline allowing the driveshaft to spin unbalanced because of the slop.

If this is what it is, use only Toyota joints. I have yet to find one available at a parts house that is worth more than scrap.

 

[BrandonF]

My guess is rear driveshaft U Joint at the axle end. Fairly common for everything youre talking about it doing. When under load, the u-joint binds up in a sense keeping anything from vibrating. But as soon as you coast there is no torque on the driveline allowing the driveshaft to spin unbalanced because of the slop.

If this is what it is, use only Toyota joints. I have yet to find one available at a parts house that is worth more than scrap.

The interesting part is how suddenly this issue has sprung up. It's not like this has been a gradual thing where the u-joint has become more and more worn over time. Just on saturday, it started suddenly and since then, its worsened significantly.

 

[BrandonF]

UPDATE:

I got under the vehicle and checked... My rear u-joint is totally split open and has a ton of play in it. To top it off, the bearing inside the transfer case where the rear drive shaft enters is totally shot and causing an oil leak.

I just lubed both driveshafts 2 weeks ago. Everything was tight and leak free.

I have two questions: is it likely that one end went, caused played, and thereby caused the other end to go as well?

Second: Is it ok to drive around town while I work on arranging to fix it? Below 45 mph, no vibrations can be felt. Also, would it be ok to fix the driveshaft end first to fix half the problem, and then continue to drive it while I get the transfer case fixed? (As this will be much more difficult and time consuming). Or, will the new u-joint quickly deteriorate because of the remaining play in the transfer case bearing?

 

[541joseph]

UPDATE:

I got under the vehicle and checked... My rear u-joint is totally split open and has a ton of play in it. To top it off, the bearing inside the transfer case where the rear drive shaft enters is totally shot and causing an oil leak.

I just lubed both driveshafts 2 weeks ago. Everything was tight and leak free.

I have two questions: is it likely that one end went, caused played, and thereby caused the other end to go as well?

Second: Is it ok to drive around town while I work on arranging to fix it? Below 45 mph, no vibrations can be felt. Also, would it be ok to fix the driveshaft end first to fix half the problem, and then continue to drive it while I get the transfer case fixed? (As this will be much more difficult and time consuming). Or, will the new u-joint quickly deteriorate because of the remaining play in the transfer case bearing?

Likely the u joint caused the tcase to go bad and. No it's not safe to drive at all. You could lose it driving causing it to go through the gas tank floor panels and even fly out and hurt or kill someone. It's not something to take lightly.

 

[fatherdoug]

This just happened to my son's '98 limited with 3.4 auto transmission. The damper on the transfer case broke off. The shaking happened immediately after the damper broke.(he saw it fall off the vehicle in the rear view). That is when the violent shaking started at speeds above 40 mph.

I can't for the life of me find a replacement, other than a dealer part for $350!

Anybody have a source? Part number is 33183-35050.