1988 Bronco Vibration
 

I bought my Bronco late last year. Drove perfectly with no vibration.
Then suddenly it started vibrating.
It has oversized tyres (put on by film company to film power rangers).
But remember...it drove perfectly for months.
It vibrates at 50km per hour almost on the dot and staying vibrating only on acceleration. Does not vibrate when I take my foot off the gas.
The Bronco is also jacked up by the looks of things.

My mechanic (who I don't have a long term relationship with...) has tried wheel balancing, adding the wheel nut spacers and now says it is because of the angle between gearbox and diff. But that doesn't explain the perfection until recently.

My husband who I trust implicitly to do his research and know his stuff says if it is because of the 'angle' between gearbox and diff, then the issue is likely the drive shaft universals - which have prolly been under extra strain and have now gotten sloppy which causes the vibration.

Since we are both new to these types of vehicles wondering if someone here has had the same issue?? I have read the blogs and I can be confident it isn't the wheels...kind of .

start with the u-joints, the cardan joint really needs to be looked at. check the rear output from the transfercase too. could be a bushing or a bearing either loose or needing replacement.

Thank you for the speedy response.
 

Will check as you suggest.

Let us know what you find. I share the same vibration and have a brand new Tom Woods driveshaft and good pinion angle.

definitely check the pinion angle, even though it was not vibrating before it can make the u joint wear out prematurely and cause that. Also look at the drive shaft really well and see if there might be a weld mark, there may have been a weight on there that popped off.

when was the last time the transmission was serviced?

After installing my 6 inch lift from Skyjacker , My bronco did great .When I regeared it to 488 is where my problems started. I too developed a vibration around the 45-50 mph range after close to 100 -150 miles I cannot remember the shim degrees supplied with this kit but I ordered new shims ,installed them and vibration - gone--Finally!!!!! The guy who regeared it went back into the rear axle .(thinking it may been his problem).I called many experts in the field of drive lines, searched forums and did my angles to figure out what degree I needed.(In the meantime installed all new u joints-double cardan inc.) Advice as stated above Pinion angle,-Driveshaft(weight on drive shaft) -U joints-Tires(weights)(Tires out of round)Wheels(out of round)Transmission/transfer case. Since you mentioned jacked up , it may have a lift kit with out the proper shims .Your angle even with just one degree off causes problems Mine did Good luck TR

i need to get shims as well under mine. I am thinking a 4* but will pickup a 6* as well just incase

Stock wedges are 8. If you put a lift in, it's supposed to have the wedges provided by the lift springs AND the stock wedges. The cast steel stockers are prone to cracking so I purchased some milled steel wedges off of eBay to run in conjunction with those provided by ProComp's springs.

I will look and see what degree I used .I actually took an angle gauge and measured .There plenty of info on the net about doing this procedure. Schwim, I agree but an actual measurement is better.I used WFO CONCPETS in Auburn Ca.(card sits next to my computer)I drove the truck before regearing and it was not that noticeable. After the regear The vibration was noticeable and after i measured and installed the shims it was completely gone.TR

I don't know. I suggested that to my mechanic, but he won't follow that avenue of research. He wants to only focus on the lifters and get a engineering firm to look at it. Which is plausible too.

Hi there BF, I couldn't agree more that it would be the best method. Would you mind sharing your method of determining your angle of dangle and the needed shim? I'd love to know what I should have.

It may seem like an obvious process, but the chunk is odd shaped so I wondered if maybe you did a perpendicular angle off of the yoke face.

Thanks!

Were you aiming for a 0 degree angle at rest? Some say to aim for 1, due to the wrap under load bringing it closer to a 0 degree angle, which is when you need it.

Lifters are not going to cause the vibration your talking about. sounds like you need to find a new mechanic. getting to the lifters is tearing into a motor that doesnt need it. if lifters were an issue you would hear tapping. frankly the injectors make a tapping sound as well.