I need some help I have a 92 Toyota pick up. It's got 205,000 miles on it and it a extended cab 5 speed manual. I have been getting really bad vibration at 40 to 60 mph and can't seem to figure out what it is. I replaced my 4 I joints on the rear drive shaft and the carrier bearing still have the vibration. I don't believe it's anything in the front end I replace the ball joints, pitman arm, idler arm, tie rods, steering stabilizer and link kit at 200,000 miles. If anyone could let me know what they think or have had the same issue let me know thanks. I have NOT replaced the u joints on the front drive line but they don't seem to have any play.

 

Manual or auto tranny? All mounts tight?

 

Is the drive shaft clean? any mud stuck on it? How about your tires, have you lost any weights or has it been a while since the last time you have had them balanced? Sometimes these small things act weird.

 

Drive shaft is clean and I just had brand new tires put on it only a few thousand miles ago and today I went and had them rebalanced still have the vibration.

 

Can you hit these speeds in other gears and have the same out come? Wondering if it is RPM based.

 

Manual transmission

 

No it's not rpm based it just does it at those speeds also it's odd it doesn't do it as bad when I am accelerating hard or when I left off all the way it kind of a sweet spot between the two if that makes sense

 

hows your suspension? new, old? any leaking shocks? im doubting it but i dont know your rig.

 

I put brand new shocks on it at 195,000 miles which was a bout a year ago they still look fine. I also just changed my transmission fluid transfer case and front and rear differential fluid. Nothing scary looking the fluid looked rather clean and no metal pieces in it.

 

Is the vibration physical? As in say the bed shakes? Or noise based. Have you rotated the tires around. Years ago I had a shake to the tune that it would lock the seat belts. I think it was a rear rim as when I moved the rear to the front it stopped. well by 99% it stopped.

 

Bearings, are they good, any damage from off roading that may have hurt the axle? (i don't think the axle one but some thing to trouble shoot)

 

The whole truck shakes. Have rotated the tires and doesn't make a difference. When I replaced the u joints it did help and I had a joint that was pretty bad. But it still vibrates pretty bad. I'm just at a lose. Would wheel bearings cause this? There is no unusual noise. What about a bad rack and pinion? But wouldn't I have seen signs of that when I changed the fluid such as really metallic oil or pieces of metal in the oil?

 

Not 100 percent on the wheel bearings if that's what you are referring to. Off roading I take it pretty easy and really just drive on dirt roads during hunting season. I don't climb or go mudding or anything extreme.

 

It definitely sounds speed-based and it sounds like it's something central.....something that would give that feeling throughout the whole truck.

Gear teeth have a 'drive' side and a 'coast' side. When you're on the gas the engine is driving all the gears, but when you're off the gas all those gears switch to the other side of the teeth so in either of those situations you have pressure on the driveline.....either from the engine or from the force caused by the momentum of the truck being counteracted by the tires on the road which slows the truck down. This keeps the driveline 'tightened up' it's just a matter of which way it's tightening (I really hope that makes sense). BUT, when you're just kinda cruising along you hit that middle-ground you're talking about and there are times where you're floating back and forth between both sides of the gear teeth.

I would check the bearings on your rear transfer case output and also check pinion bearings on your rear axle. Both of them spin the same based on speed rather than RPM's, it's just a matter of whether they're being spun by the engine or the tires/momentum of the truck. When the driveline is loosened up and the pressure is off it that could cause a bad bearing to show its ugly face. The transmission output spins the same, but the transmission is locked to the input of the transfer case so there shouldn't be any play there that would cause a bearing to wear out. The other 2 are much more likely to go first.

 

Drop the front drive shaft and test again.

And check that all the grease fittings on the rear drive shaft are lined up or in the ABC possioning that the FSM shows.

 

That makes sense I have checked the pinion bearing when I replaced the pinion seal and it looked good. I will check the transfer case and see. Thanks. Also I will try to drop the front driveline aswell. Could I drop the rear drive line and put it in 4hi and check it the other to see if it's for sure the driveline or not?

 

IT'S FIXED!! Turns out the original owner of the truck must have played with the drive line in the past. It was way out if fase took it to a driveline shop and the guy balanced it and put it back in face also taught me a thing or two about drivelines while he worked on it. Didn't even end up charging me real nice guy. I didn't notice it was out of fase when I did the u joints I just put it back the way it was. Thanks for your help guys!!!

 

GREAT. A good ending.......

 

that was my thought as i read through the thread!!

Glad you got it fixed and learned something as well