Driveline vibrations/t-case dampener. Help?

[99Runnr]

I have a 99 sr5, blah blah. 4x4, manual trans, 3.4 engine. Manual shifted t-case, whichever number that is, not the push button.

My question/concern is;

Driving down the freeway, 60-75 mph, if I let off/coast down a hill essentially, it suddenly sound and feels like I'm almost driving over a mesh metal grid. A dull vibration/rumbling feeling and noise is heard. Hopefully that adequately gives someone an idea of what I'm experiencing.

U-joints feel fine, not lifted, new shocks, new tires, professionally balanced using road force function, alignment is good, good fluids, no leaks, nothing out of the ordinary or obvious.

I did replace a clutch about 2k miles ago now. When I replaced the transmission (long story), it was the same style t-case. However! The NEW t-case didn't have a rubber dampener it seemed, off the right hand side. I asked the guy I purchased the stuff from and he advised I use it from my original t-case.

My question; Did all/some/most 4x4 trucks have this dampener? Was it specific to any trim level/model? I can reclock the driveshaft since it seems to be a minor balance issue, but I'm looking for a bit of feedback before I'm just guessing at crap.

 

[99Runnr]

I did try searching some as well. Concluded it's a damper or dampener. Nobody seemed to have a rhyme or reason it was there though.

Lots of people stating no charge by removing it. Maybe I missed something important about clocking the driveshaft as I said?

My truck isn't on the freeway much. This weekend was another 5 hours round trip and I definitely noticed it a few times. This is going on 20 years old. Maybe it's normal? My bushings are also good on the control arms. Haven't pulled the panhard bar to inspect closer.

Any insight appreciated

 

[TheDurk]

I did try searching some as well. Concluded it's a damper or dampener. Nobody seemed to have a rhyme or reason it was there though.

Lots of people stating no charge by removing it. Maybe I missed something important about clocking the driveshaft as I said?

My truck isn't on the freeway much. This weekend was another 5 hours round trip and I definitely noticed it a few times. This is going on 20 years old. Maybe it's normal? My bushings are also good on the control arms. Haven't pulled the panhard bar to inspect closer.

Any insight appreciated

I have the exact same truck, 99sr5, 5-speed, 3.4, 4x4. It is definitely not normal. I'm pretty sure the damper has nothing to do with it. As you said, lots of people do fine without it. I'd suspect driveshaft first but I have never experienced anything like what you describe, unless there was actual metal mesh.

 

[LookAtThatDog]

Does pushing in the clutch do anything?

 

[Unner]

I have Shrockworks skid plates and you have to remove the damper for the transfer skid plate to fit since it tucks up so close. I don't have any vibrations when driving, the only time I notice any difference is a slight rumble or vibration backing out of my driveway and at stop lights it'll sometime have a slight vibration, but nothing bad at all. Nothing when the truck is actually moving down the road. I think your problem is probably elsewhere.

 

[gamefreakgc]

The high speed vibration can be caused by multiple suspects. Interesting it only shows up on deceleration though. Mine was a combination of bad tires (out of balance) bad aligment, bad ball joints and a leaking steering rack.

It's all good for me now. The only thing I didn't have to touch was the driveshaft, which funny enough is usually the culprit for high speed vibrations.

 

[99Runnr]

Right.
I have been replacing a ton of stuff since I got this truck. I think I'll inspect the flange maybe for marks if it was clocked. By the time it was going back together I didn't waste anytime staring at it you know?

It is only noticed at speeds over 55. It occurs and not even everytime, as I'm coasting in gear or the grade is descending and it's in cruise while the engine isn't doing much.

Definitely seems driveshaft related. Even when this happens, the transfer case and manual shifter have minimal vibrations. I feel nothing in the steering wheel.

It's pretty odd really. Seems to just resonate and exist in the cargo region of the truck.

 

[St Runner]

Since you have a j shift transfer case on a 99 somebody had to pull the driveshaft off. Hopefully it was marked before it was pulled. If there are no marks you might want to pull it off and get it balanced and see if that helps

Edit; I was thinking the 99 and up did not have the j shift but I was wrong Still won't hurt to check the ujoints and balance the driveshaft if you feel that is the problem

 

[99Runnr]

Since you have a j shift transfer case on a 99 somebody had to pull the driveshaft off. Hopefully it was marked before it was pulled. If there are no marks you might want to pull it off and get it balanced and see if that helps

Edit; I was thinking the 99 and up did not have the j shift but I was wrong Still won't hurt to check the ujoints and balance the driveshaft if you feel that is the problem

Yea, I am going to make an effort to check it out this week.

I will go an verify it vibrates in neutral as well as in drive, since I don't recall verifying that.

 

[KidVermicious]

Vibes only when you coast kinda smells like slack in the drivetrain to me. If the ujoints are tight, how are the splines in the slip shaft? Tcase output bearing or pinion bearing?

 

[99Runnr]

Vibes only when you coast kinda smells like slack in the drivetrain to me. If the ujoints are tight, how are the splines in the slip shaft? Tcase output bearing or pinion bearing?

The trans and transfer case I got had just over 100k on them. I'd suspect my 220k rear end before that.

I will check it out and see what I can figure out. It does have a bit of slack though, I always feel it when I take off to the stop sign and let off the gas. Never felt excessive, but I'm very conscious about vehicle behavior when I drive.

That is nice about these trucks, lol. If the rear end needs work, or the t-case, I can just drive and go get new stuff. Not really a big concern, stuff is cheap, who cares. I have an e-locker rear though, probably worth rebuilding if necessary.

 

[TheDurk]

Well, you can always just remove the rear driveshaft, and then try driving in 4wd using only the power to the front wheels. If your vibration goes away, then take the D/S to a driveline shop and have them fix it. If it doesn't then you have to look elsewhere.

 

[gamefreakgc]

Right.
I have been replacing a ton of stuff since I got this truck. I think I'll inspect the flange maybe for marks if it was clocked. By the time it was going back together I didn't waste anytime staring at it you know?

It is only noticed at speeds over 55. It occurs and not even everytime, as I'm coasting in gear or the grade is descending and it's in cruise while the engine isn't doing much.

Definitely seems driveshaft related. Even when this happens, the transfer case and manual shifter have minimal vibrations. I feel nothing in the steering wheel.

It's pretty odd really. Seems to just resonate and exist in the cargo region of the truck.

If you don't feel it in the steering wheel you can rule out all steering components and ball joints. As long as you are sure your tires are in good shape and balanced, that only leaves the driveshaft as the possible issue in my mind.

 

[99Runnr]

If you don't feel it in the steering wheel you can rule out all steering components and ball joints. As long as you are sure your tires are in good shape and balanced, that only leaves the driveshaft as the possible issue in my mind.

Yeah, I didn't suspect the suspension components really, because they are all pretty much brand new. Under 500 miles on CV axles, LBJ, inner/outer TRE's, my personal friend balanced and mounted my new wheels. The balancing machine is 6 months old, uses lasers for weight placement, looks at the wheel and hides them behind spokes. Anything is possible, but it's really seeming like I may have clocked the driveshaft wrong.

I just got some nice extended box wrenches I can use to adjust the driveshaft. Wrenching with bronchitis for the last 4 weeks has me slightly less then motivated. So hopefully this is simple.

 

[Volumetrik]

I have a 99 sr5, blah blah. 4x4, manual trans, 3.4 engine. Manual shifted t-case, whichever number that is, not the push button.

My question/concern is;

Driving down the freeway, 60-75 mph, if I let off/coast down a hill essentially, it suddenly sound and feels like I'm almost driving over a mesh metal grid. A dull vibration/rumbling feeling and noise is heard. Hopefully that adequately gives someone an idea of what I'm experiencing.

U-joints feel fine, not lifted, new shocks, new tires, professionally balanced using road force function, alignment is good, good fluids, no leaks, nothing out of the ordinary or obvious.

I did replace a clutch about 2k miles ago now. When I replaced the transmission (long story), it was the same style t-case. However! The NEW t-case didn't have a rubber dampener it seemed, off the right hand side. I asked the guy I purchased the stuff from and he advised I use it from my original t-case.

My question; Did all/some/most 4x4 trucks have this dampener? Was it specific to any trim level/model? I can reclock the driveshaft since it seems to be a minor balance issue, but I'm looking for a bit of feedback before I'm just guessing at crap.

I have the same exact truck as you, 99 SR5 5MT 4x4 and I get the exact same noise as you when on the highway. Only on decelerating or coasting. The truck has 268k km (166k miles). I am currently fixing a hole in my floor, but the next thing on the list is the coasting rumble.

Just wanted to let you know you are not the only one having this weird noise.

 

[gamefreakgc]

My only complaint with 3rd Gen 4Runners is the amount of vibration and steering issues that we get. However, considering most vehicle's main issues are engine or transmission failures, it's not really that bad.

 

[Wikano]

If you have had the drive shaft removed lately, try re-attaching the drive shaft at the third member by 180 degrees. Mine had a vibration at 68ish mph when off the pedal because it was "out of phase" and now it's gone. It is also in the troubleshooting part of the Haynes manual.

 

[Steve240]

I had a similar vibration but it was during acceleration rather than decel. Mine was corrected by replacing the u-joint in the drive shaft at the diff. It felt okay when it was on the truck but once I had the drive shaft off I could feel the free play. Its fairly inexpensive and an easy job so I would start there if you plan at throwing money at the problem.