Little history on the truck. 2003 Mazda B3000 Dual Sport. Regular cab 2 wheel drive. 3.0 liter with 160000 miles. About a month ago, noticed this vibration starting at about 50-55, very slight....but enough to recognize. Gets worse as speed increases. 65-70 it becomes real bad. The steering wheel was not vibrating, the cab, my seat.....basically the whole truck. Once you get above 75, the vibration is still there, but not as bad. Tires at that time were showing really bad wear on the inners of both wheels. So, since then I have done the following:

new cooper tires
new front wheel bearings
front end alignment and tires rebalanced
rear drums, wheel cylinders, new shoes of course
replaced upper control bushings and new upper arms
universal joint in the rear/ drive shaft was terrible. Rusted really bad on one corner

After all of this, the vibration is still there. I have a friend that has worked on fords his whole life and his shop replaced the u-joint, balanced the tires and aligned the front end.
i am supposed to drop it off with him sometime next week to see what else he can hunt down, but I wanted to hear other folks opinion. This is really starting to drive me crazy.
I really thought we had it yesterday with the ujoint, but it was still there.
Thanks

 

If possible go down hill at a speed where you can feel the vibration, then shift to Neutral and coast letting engine and transmission RPMs drop to see if thats where vibration is coming from

If vibration stays then I might balance drive shaft since most other things have been repaired or replaced, you can DIY that with hose clamps, Google: diy driveshaft balancing

If vibration changes with RPMs:

Check motor mounts
Open hood
Start engine
Set parking brake
Put on 1st gear or drive
Look under hood at engine
Let out clutch a bit or give it a little gas
Engine should lift on one side but not much
Then press clutch in or let off gas quickly, listen for a noise

Repeat but in Reverse, engine should lift up on the other side but just a bit

Fan clutch
engine off and cold
Check for wobble on fan blade
After engine is warmed up but OFF
Check for wobble again

 

Thanks RonD. I will have to try the downhill test a little later. I did check with truck in drive and reverse, motor does lift side to side while giving it the gas. I can’t really feel much play in the
fan. That’s with the motor warm. All the blades appear the be in good shape. I did check each blade to make sure there were no cracks. I will look into the drive shaft issue soon.

 

Did you replace all 4 tires or just the 2 wore ones ?

 

All 4

 

It wasn't much of a hill RonD, but this morning I push the truck in neutral when the truck was in its vibrating mode, and there was no change. Vibration was there, no matter if the truck was in gear or neutral

 

Good, so you know its not an engine or transmission related vibration so you are left with 4 wheels and 4 tires, and the drive shaft
Because it happens at higher speeds 4 wheel "mis"-alignment is a possibility

Were the new tires done with road force tire balancer, its a long shot since old tires had the same vibration, but not a no shot

 

u-joint on other end of drive shaft
Transmission mount
rear pinion bearing
Transmission tail shaft bushing

 

not sure if they were road force balanced or not. They have been balanced twice by 2 different places, ending with the same results. I am wondering if I may have
a warped rotor? I did notice when I was redoing the front wheel bearings that .....I’m thinking it was the inner pad on the passenger side, seemed to be wearing
at an angle. I have also noticed the brake pedal starting to pulsate when braking. Not bad, but you can tell it’s there. I have a local home town shop that still turns
rotors. I think I will have them turned next week.
i may try the diy driveshaft deal after that.

 

buddy says he looked at all of those as a quick glance, but didn’t see any wear. Still searching. Thanks for the input

 

Had the front rotors turned yesterday, so the pulsating brake pedal is gone. Today I played around with the DIY driveshaft balance and had no luck. I guess I will drop it off at my buddies and let him keep it for a day to see what he can find.

 

changed the front 2 shocks and it has ridden the best it has for 3 months. still not completely gone, but better. I think I will just deal with it

 

changed the transmission mount, vibration still there. I don't know what else I can throw at this thing, looks like I will seek professional help

 

Last and final update....SUCCESS.becuase
First of the week I dropped the truck off for my buddy to see what he could find. they first called and said I had a bad tire. I reminded them that the tires were new and of course their response was the tire could be new but still be bad. I said I get that, but if yall would have paid attention when I dropped the truck, I told you the whole history of this and it started with the old tires, even before the new tires. So, their final diagnoses was the drive shaft was bent. They don't repair or do anything with them but they have a guy in a nearby town that they take them to and he fixes them.....but that is a long drawn out process, you have to make an appointment with the guy, then somebody drives it over and waits blah blah blah. their opinion was to buy a used driveshaft and go that route, but they couldn't locate one. So I left and they were going to see what they could find and get back with me. So I started doing my own research. I knew the town where the driveline guy lives so I googled it and sure enough found the place and called the guy. He said yeah.....bring it over (didn't need much of an appointment).
So I took the shaft out myself and rode over to his shop today. The guy takes a look at the the new u-joint my buddy put in and makes a comment about its not all the way in and starts aligning the u joint "a little better" he says. Puts it on his machine and says, well the drive shaft is not your problem, that its as smooth as it gets. so I thanked the guy and made him take 20 bucks for his trouble said take the kids to get some ice cream. Ends up, that when my buddy put the new u joint, it wasn't quite installed right. vibration gone....truck rides great. I called the guy back and thanked him and to let him know that he did actually fix it.
They always say take your vehicles somewhere and let the professionals fix and I by no means is knocking my buddies shop, but it just goes to show you even the shops can screw up. I just wanted to put a nail in this one because sooo many threads get started but are never solved. Thanks to all the folks that chimed in with suggestions.

 

Good stuff

That's the way we all learn, by our mistakes, that's what sticks, success's are great but are soon forgotten, lol