My '97 T100 4x4 has my irritation levels high as of late. The shifting trouble may be due to the clutch pedal bracket that I've just read about, but the vibration and mechanical whirring noise when letting off of the accelerater in the higher gears are really starting to make me nervous.
The vibration occurs around 45 mph. I've replaced the tires, had the balanced and had an alignment done, and I still can't get rid of it. It gets even worse when I have a cabin full of people (Xtra Cab). DOES ANYONE HAVE ANY IDEAS?
The mechanical whirring sound is similar to the sound you'd hear if you were moving in reverse and you let off the gas.
It's sad, but the 89 SAAB turbo I'm driving instead has 280k original miles on it, and it runs a hell of a lot better.

I'm hoping one of you have some insight, as I know that I'll pay out the ass to have someone else track down the problems.

 

I'd have the rearend checked out for the whining. If one of the bearings on the pinion has gone south it will cause everything to bind up and make a noise similar to what you describe. And for the vibration have your driveshaft checked out. Over time they go out of balence and when they do it can cause u-joints and output shaft bearings to fail. Which may explain the whining. Hope this helps.

Andrew

PS What do you mean when you say that the noise is worse in higher gears, which ones. I've heard and about and had problems with high mileage manual trannies and the overdrive gear.

 

In fourth and fifth gear there's a whining noise when you let off the gas to coast. You can hear it to some extent in the lower gears too, but my commutes rarely have me in those gears.
It only happens when I'm coasting (i.e. if I'm going down a hill and doing the same, there is no noise). I can maintain the noise if I just give a little gas while coasting along (between 1500 and 2500rpm), but not enough to accelerate.
She goes into the shop on Monday. A friend of mine also suspected the drive shaft for the vibration, but that's not something I'm equipped to work on.
Thanks for the help, I'll definitely have the mechanic look to the drive shaft and rear end as the probable source of my troubles. I'm highly confident that it's not a tranny problem, as the noises do not seem to hail from that area (amen).

Thanks again.

P.S.- Do you know if there is supposed to be a dust boot over the shift fork where it goes into the tranny? If there is, let me know ASAP because the jackass that put the clutch in before I bought it didn't replace it, and I need to throw one on there.

 

There is no dust boot as far as I can remember. There is only a metal cup with a spring below it to seal everything out. Hmmm... from what you wrote it sounds like one of the pinion bearings did let go. Has the seal around the pinion output ever leaked any fluid? Or one of the carrier bearings is allowing the carrier to move around when you let off of the gas. Hope that helps

Andrew