Vibration while decelerating / after letting off gas

Hello Everyone,

I'm new to this forum, live in Las Vegas so if there is a local group please let's get in touch! This is my second Taco, I owned an '05 6spd manual a few years back.

I've seen a few threads about drive shaft vibrations but not one that quite fits my scenario. I recently bought a used '04 4WD 5spd manual taco. 93K on it, I believe original suspension riding on 265/70R16. Doesn't look lifted more than stock. I'll add some pictures to my profile tomorrow.

The issue I'm feeling: I noticed this first while at highway speeds on the drive home. I'll accelerate up to 60-75 and nothing out of the ordinary for having A/T tires. As soon as I let off the gas I notice a slight vibration that I original thought was resistance from the trans slowing me down. However, the resistance/vibration and slight noise (almost a humming, no whining) persists even if I put it in neutral. As soon as I apply the gas again, it clears up 100% and rides smooth again. I'll do another test drive to confirm this happens at all speeds but it was most noticeable at these higher speeds.

I read a few other posts that pointed to possible causes:

- u joints
- drive shaft(s), rear differential angles
- pinion bearing/seal
- wheel bearings

Before I go throwing parts at it I want to make sure I have a fair diagnosis first. I've done most of the maintenance on my previous cars, mainly suspension, cv axles, wheel bearings, control arms, etc. but nothing related to the transmission or drive shafts so this is a learning curve and I'm slightly hesitant.

One more note worthy thing that I wrote off as rotors/drums need replace is a harder more pronounced vibration in the steering wheel and front end (mostly) when braking, the harder I push the brake the more vibration I would get. I've already ordered the parts to replace rotors, pads, drums, and shoes. So I'm 90% sure that will take care of it and it's unrelated.

I have not yet jacked it up to check the wheel bearings (6 & 12 test to check for play) but will do that this week.

Any input and thoughts is much appreciated. I'll try to be as responsive as possible. Thanks!

 

For anyone who may stumble across this thread the cause was a busted center support bearing and the flange/yoke coming from the Double Cardon Joint that slides into the center support bearing was worn out and trying to slide out of the center support.

Dan's Driveline in Vegas fixed it parts and labor out the door for $325. More than I'd like to pay but worth it for the time and energy it would've taken to do it myself with limited tools.

 

Don't overlook the tires. I chased a vibration and replaced coils and shocks up front, rear shocks, stabilizer bushings and links, and then a bad inner tie rod.......but one of those had caused my front tires to cup and I didn't see that. I was getting a vibration at 35-50 MPH. Moved the cupped tires to the rear since I had already replaced what was likely causing the cupping. Then I reduced the tire pressure to the recommended 26 (265/75R15) and that's made it a good deal better.

 

@mac84, definitely sound advice. The support bearing and yoke were the root cause. The tires are brand new, for good measure I had them balanced, rotated, and inflated at discount tire. I'm vibration free.

 

Having that nagging problem go away is a good feeling! Funny how we fixate on thing like that.....I used to get in the truck and look for the vibration!

 

Ok probably it's too late
But my 95 2wd when pressing acceleration like 20 to 40 and let off gas pedal truck shakes side by side I put new shocks all around inner tie rods and outer ones same u joints does have play center bearing good what could be

 

Sounds like driveshaft u-joints. Drop the shaft and see what the joints feel like. Might be worth checking that your lug nuts are properly tightened if you just had the wheels off.

 

My experience for those who buy these trucks at 20yrs + .... a lot of you have a ticking time bomb.

My guess is about half of you are driving around with rusting needle bearings in your UJ's...

You'd be surprised how fast those turn to dust after that point...