65-75 mph vibration

[thewishkah]

I have that oh so famous vibration/shake at 65-75 mph , In another thread someone had mentioned that if i add a second washer to my RA bushings this would help a bunch. Now I didnt want to jack the thread so heres my question would this help even though my RA bushings AND mounts were replaced like 1 1/2 years ago?the bushings are urathane bushings if that makes any difference.

p.s. I always thought it was something to do with the rear end that vibration. But I could be wrong and probably am. thanks for the help, Jon

 

[ExplorerDMB]

Usually a vibration that comes and goes is a balance issue (not just wheels though). I'd first, though, look at the wheels and possibly get them balanced to see if that changes your issues. Personally, I don't think the bushings are your problem.

-Drew

 

[thewishkah]

all the wheels are balanced , I have had this issue for a very long time with different tires and diff shops doing the balance. My whole front end was re done about 1 1/2 years ago from RA bushings and mount,bearings,upper and lower ball joints,and allignment, it was like that before and after. with minimal change.

 

[wee]

I have that very same problem with my 01 Sport. I thought it was because my shocks are blown and my tires have/are cupping. I will find out soon enough.

 

[dejello]

Since tire/wheel balance doesn't seem to be the issue, check your u-joints in the rear driveshaft. Does the vibration go away if you let off the gas during the speeds you mentioned and return if you hit the gas? If so, it is most likely your u-joints.

 

[thewishkah]

Its constant at those speeds wether im on the gas or not I had read somewhere on here like 2 years ago that it had something to do with the back axle and that almost all of them did that, atleast thats what I remember reading lol. I apreciate the help you guys are trying to give me. It was something about the harmonic balance between the front end and the rear end or the frame and the axle?

 

[Jason94sport]

He's talking about the normal shake with 1st gens at that speed. It's nothing to do with wheels, tires, balancing, or u-joints.

It's how it is. Most have it, some don't. You can pull your hair out trying to fix it, live with it, or get another SUV.

I tried the washer & it didn't do anything for me.

 

[RKR]

I have just gone through this exact same problem on my 96, Auto. I replaced almost everything and have recently found out that its the rear output shaft bearing on my Tcase. If you look under Trans and Tcases forum on this site, jamieh560 has thread dealing with the same problem. I felt kinda stupid for not finding my problem right away, but if you didnt just grab the rear drive shaft right, it wouldn't move. Once I got it to move it is very pronounced.

 

[Jason94sport]

Again that's different though. You have a 96. It's possiable, but unlikely.

 

[Rhett]

I was the one that suggested the extra washer in the other thread. That doesn't ALWAYS do it...as the causes of the shake are many and varied...everything from average tires to the transmission mount...

My opinion is that the 65-70 shake can be cured in every single 1st gen, and it is not something that is inherent to these vehicles. Every vehicle fault has a cause, and every fault can be cured.

The thing about the rear causing it, is something that I believe originated from discussions on the topic regarding 2nd gens, who often have a shock mounted between the frame and rear axle. I've never seen a 1st gen with a well-functioning diff, straight leafs, frame and axle that shook because of the rear.

My truck did it when I bought it, and I solved it, eventually. My friends 93 XLT did not do it.

Check the thread on the transmission mount, also. There's literally dozens of things that can cause the shake, and surely you have not replaced all of those things.

 

[Jason94sport]

My opinion is that the 65-70 shake can be cured in every single 1st gen, and it is not something that is inherent to these vehicles. Every vehicle fault has a cause, and every fault can be cured.

If you want to spend lots of time & $$ tring to fix it.

My old 94 sport didn't shake. My current one does. I live with it.

 

[thewishkah]

I guess I will live with it the way it is, I am going to be changing all my swaybar bushings with urathane ones soon, I know that will not likely do anything but I will check all those other things when I have the truck on the stands and see If any of them are atributing to the shake.

just 1 more quick question, I had my tranny replaced a year ago including torque converter,and case, a complete tear down with all new parts , a shift kit, had it routed to not run through the radiator, and heavier bands, If the mounts were shot then wouldnt they have told me or changed them? just a thought, It did this shake before then as well.