Hello all. I drive a 95 Blazer 4Door 4x4 with 214,000 miles on her. The engine is strong, and most things are in great working order. However whenever i drive on the freeway im constantly playing with my car and hoping she doesnt break down then and there.

Everytime(sometimes) i go over 45 and keep it at that steady speed, and then slowly raise the speed and rpms, i get a horrible vibration. Like i have two huge subwoofers in the back just hitting constantly, if i let off of the gas, it stops, or if i gun it, it stops.

Another examples is, say i put on cruise control, and am going steady at like 70, if i go up a semi steep grade(nothing too big, just enough to raise RPM's, it will do that until it reaches the top of the grade)

As for the weeble wobbles, they did that on the freeway off and on, nothing too serious, got her balanced/ rotated/ aligned. and took care of that problem for the most part.

Im pretty sure the ball bearings need to be replaced, and im sure the 4x4 needs a servicing too, just because the previous owner cared alot about engine/tranny, yet my suspension is suffering!

Does anyone have any other ideas of what it could be? I thought transmission for a while, but im hoping thats not the case(tranny and engine rebuilt 71,000 miles ago.)

Thanks!

 

possible your rear rotors?

 

Sounds like the problem I had, its your U-joints probably the rear since thats where you feel it. Have a shop or yourself check for slop in the rear Ujoints (near the rear differential on the drive shaft. Otherwise Hub bearings should not cause this problem but you would here them (especially while turning). I would bet money that it is the U-joints though cause that is the exact same description I had when mine went bad. Anything over 55mph was horrible and going up inclines was bad, never noticed it in the city, till i started getting some clicking, but I would definately say it yours u-joints. should be about $150-$200 repair at a shop, or maybe like $50 if you do it yourself.

 

Sounds like u-joints, if there is slop in the drive shaft!! If you buy the u-joint yourself and take it to a shop all together shouldn't cost but 100-150 all together!!

 

I'm wondering if this isn't a case of torque converter shudder... Light throttle is where the torque converter should be in variable lockup mode which may explain this situation if the converter clutch plates are warped. Next time this happens, tap your brake pedal (not enough to actually slow you down). If the problem goes away, it is definitely the torque converter as when the brakes are applied, the torque converter fully unlocks.

How does the transmission fluid look? Is the fluid level appropriate?

 

Yeah. Some other guy told me the U Joints. I saw them for really cheap at my local auto store. I think ill see if i can get my cousin to do it for me.

There's two U joints right? Front and back?

 

yeah two, one in each end of the rearmost(main) drive shaft. Drop the shaft and focus closely on the rearmost one. 90% or better of the time this is the problem. Or do both if you want to but if myself were doing it, I'd do only the bad one and if it were one, I'd do one. JP[X(]

 

Be aware that some have injected nylon to lock the cups in the drive shaft. This can be a bit of a pain to remove. If you do not have a press, it is even more fun. The yoke will have to be heated to melt the nylon while you press the cup out. I will typically heat the yoke until the nylon starts to come out of the injection hole then set it up in the press (or vice). Heat it a bit more then press the cup out.

If you do not have a press or a vice, some shops will press out the old cups and press in the new ones for a fee. One thing that must be done between removing the old cups and pressing in the new ones is this... You have to file down the insides of the yoke where the new c-clips will ride. If this step is neglected, the joint could end up too tight and wear out faster. Just like having them too loose...

 

Okay. Is there any kind of guides of replacing U joints? Im not Car expert. My cousin is a mechanic, but he works more on smaller cars, and suspension stuff isnt his specialty....

 

U-joints are not suspension parts. If he can help you and has access to a torch and a press or even just a vise, you should be able to get the job done. You have to determine if the u-joints are the cause of the problem first though.

To check, jack up the rear of your truck and support it on jack stands making sure that the vehicle is stable. Put the transmission into neutral. Get underneith the truck and grab the drive shaft. Put one hand on the driveshaft just to the front of the rear u-joint and the other hand on the yoke on the front of the diff. While holding the yoke steady, move the driveshaft around, feeling for play. If you feel play, the u-joint is bad.

For removal, basically, just unbolt the rear driveshaft where it bolts up to the rear differential. If I remember right it was a 10mm wrench that is used. They are fine thread bolts so it'll take a bit. Once you have the bolts and straps off, it may take some prying/hammering to get it loose (it did on mine). The front will just slip out of the back of the tail housing.