Suggestions concerning an odd vibration.

[2DR4EVR]

Hello all. I was trying to get some theories on vibration I'm getting. I'll try to describe this best as I can. Doesn't really match up with previous threads.

So while driving in 60-80 mph range I will often get a very high frequency vibration. I can feel it in the wheel, feet and through the dash as well as hear it. When I apply more gas, or take my foot off the acclerator it goes away........only to return when I'm holding constant pressure maintaining a speed.

It's not a rumble like a dead cylinder and its not a wobble that's steering related. It's like someone turns on a giant vibrator from somewhere under the hood or you were driving over a grated road. I had a mechanic ride along and I couldn't get it to duplicate at the time.

Some things to consider:

It seems to do it more during the day when it's hot. (I live in FL)

I'm throwing no codes when it happens

I get on occasional p1870 code....but it clears. Been battling that for while. Could be related?

I did a total rebuild during the past two years. New Jeggs engine, all new front end and had to do a trans rebuild as well as a rebuild on transfer case.

it doesn't seem to be causing any other issues.

Any theories?

Thanks

 

[laredo1307]

I would check your U-joints if it's high frequency. Also, if you've recenty replaced them sometimes you can get an imbalance in the shaft and it's usually more noticable at those higher speeds.

Also, sometimes it's hard to tell if the u-joints are going bad because they are locked in there. look for signs of material coming out at each of the joints. Once a u-joint starts to fail those needle bearings just get eaten to shit.

 

[Berserker]

Had a similar issue with my 99 burban. Ended up being a u-joint like Laredo said.

 

[Woodse]

I just had the Nickel Plated yoke installed. The dreaded clunk went away but I have the same vibration now at 65 mph. Going to pull the driveshaft next week and have it balanced.

 

[qukon 95]

the clunk that you had is this when you put in park no matter parked on flat or incline then you put it in drive and clank it don't make this sound 100% of the time.

 

[SunlitComet]

For the 1870 code be absolutely sure your fluid level is correct before you go poking around in the valve body. Low levels can suck in air and make things screwy.

 

[2DR4EVR]

Thanks for the input, fluid level is good. I had it checked today. I'll take a look at the ujoints. We did so much work to the truck that I can't honestly remember if they were looked at or not. Likely not because at the time they weren't causing any issues. I've gone through ujoints over the years. This vibration just feels,different but that's not to say it could be the cause.