Another Vibration Thread with a Twist

New moderate vibration from ~50mph to ~about 60mph. Felt through the floor & seat. And here is the twist: only in 5th gear. Exact same speed in 4th is smooth. No change if I select 4HI either. V-6, M/T, 226,000 miles. Trusted shop said no sign of u-joint issues about 2K miles back. Center bearing has some play, but nothing horrible.Thoughts?

 

Clutch slipping?

 

Mine was the slip joint. Only took 3 months to locate. Try output shaft, trans and motor mounts, rear end. Have you located a specific RPM when this happens? Acceleration or decel? Something in the trans? How bad is the vibration?

 

No

 

Slip joint was inspected/lubed ~ 5K miles ago. No issues noted. Will look at trans/motor mounts, but they were good ~ 5K miles ago. Not RPM related, just speed. (same speed, 4th gear smooth, 5th gear vibration) Acceleration & steady, smooths out on decel. Transmission seems fine in all respects. Irritating bad but not severe or extreme.

 

My driveshaft was inspected and nothing was found as well. Not until I removed it did I find the issue. Replacing the ujoints is not super expensive and might be a starting point, I know I hate throwing parts as well. The cardon joint might be wearing as well. I continued to drive mine and it got worse but also made it easier to find. good luck and please post your results.

 

I just re-read what I posted. Maybe it is RPM related as they would be different in 4th & 5th gear but don't get the vibes in 4th going up thru same RPMs to the same speed? Guess I will pull the driveshaft & see if I can find anything amiss. Will post solution when found.

 

Mark the DS and put it back exactly where it was as well as phased where it was.

 

Will do. You by any chance a black Lab owner?

 

You betcha

 

Okay updating this. Transmission shop said the vibration is coming from the T-case. A different transmission shop said he has never had a Tacoma T-case be the source of a vibration. Vibration is now felt ~45-60 MPH in 4th & 5th gears. Wheels have been balanced & rotated, tires have ~10,000 miles & show no unusual wear. I removed the rear driveshaft & took it to the driveline shop in town. They replaced the center bearing & gave the D/S a clean bill of health. Second shop has done some diagnostics: drove the truck in 4WD with the rear D/S removed. No change. Drove with rear D/S installed, CV axles removed. No change. Ran the truck on the lift up to the relevant speed in all these scenarios & not able to locate vibe. So the CV axles, rear D/S, front D/S have all been eliminated from the list of possibles, correct? I have obtained the ECGS bushing & will install next time the DS CV is out but that has also been eliminated due to running with the CV axle removed correct? So far all this diagnosis has been free. Now he says we are back to the T-case or the transmission and I am going to be out labor for R&R of the T-case & labor to tear it down diagnose/fix. (He doesn't do T-cases.) He still doesn't think it is the T-case, but thinks we need to eliminate it. Before I spend a bunch of money on this what do you folks think of trying to get hold of a Dynamic Dampener & see if it makes any difference? I don't think my truck ever had one but worth trying? See this Thread: https://www.tacomaworld.com/threads/what-is-hanging-off-my-transfer-case.332600/

 

Bump!! Somebody? Anybody?

 

Yeah, I have an idea- check your transfer case mounts. I had a vibration that wouldn’t go away after replacing front and rear shocks, swaybar links, engine mounts and tranny mounts, multiple tire and wheel combos and 7-8 balance jobs. Drove me nuts. I replaced the transfer case bushings with some press in pieces manufactured by a guy that’s here on Tacoma World. Problem solved. I apologize for not remembering the guys name, but if you do a search for transfer case mounts, you’ll find them. It was a pretty easy job btw. Ok.... I just reread what I wrote. I hope I didn’t jam anyone up with my misinformation, but what I should have written was “ Front differential mounts “ , not transfer case.

 

Vibrations that require more than one condition tend to be resonance issues. As things wear the stiffness and amplitude of vibrations change, and when they decide to add up you feel it.

Engine, transmission, and transfer case mounts soften or break and decrease in rigidity over time, resulting in a lower resonant frequency. If the issue appears more often at lower and lower rpms, then it's probably related to stiffness going away somewhere. Also consider that the speed you have to be going at may not be relevant, and may instead be related to engine load at a given rpm. I'd drive up and down a hill in fourth and fifth gear and see if the vibration varies with the throttle required to maintain speed.

I have seen vibration issues from damaged bearings near the various drive flanges due to bad modified suspension geometry, improper grease packing in the slip yoke ("hydrolocking" the yolk and causing axial loads on the bearings") and direct strikes to the drive shaft and related components. I am unsure if any of this applies to you but I would drop the drive shafts and check the drive flanges for any play.

 

I second ELMO67's suggestion but I would take it one step farther and loosen ALL mounts... motor mounts, trans mounts etc. a turn or 2 and run her down the street and back then retorque them.

 

What condition are your tires? I was starting to have some issues and I started with the carrier bearing and trans mount. They helped a little bit and when I finally changed my tires everything was smooth sailing. Just because you have plenty of tread on the tires and they look good, they can be hard as rocks and causing the vibrations. Just my 2 cents.

 

mmm I don't recall 1st gen tacomas have a separate mount for the transfer case. I mean, I just went out to my truck to check, and I am fairly certain there is only a transmission mount.

 

I don't have a transfer case (well I do but not in my truck) so I had to be general about that.

 

The dynamic damper fixed my vibration but mine was RPM specific, from about 2700 to 3100 there was a noticeable vibration from the t-case shifter, gas pedal, steering wheel and floor. Tried lots of things before someone suggested that damper on a thread I started about the odd vibration. It’s worth a try, got mine from a wrecker for 50 bucks.