Ah, I can't believe i'm back already!

I've been experiencing a bit clunk suddently while down shifting from 3rd to 2nd slowing down for red lights. It happened about 4 times now. The other day I had to back up a steep driveway, & a loud clunk was heard clunking at each revolution. No clunk/vibration if I coast/slow down with brakes in neutral. I can feel vibration also whenever tranny is in gear while letting off gas pedal to slow down. Vibration is easily felt at slower speed than high speed.

What could this be? Maybe I should have put in a decent brand name clutch 3 yrs ago? Something came loose?

FYI: My mechanic back in Quebec put in a seco korean made clutch about 3 yrs ago. While I had my engine replaced last fall, I had to put in a new input bearing to replace the one that already had play in it.

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Sounds similar to when one of my main transmission bearings went out.

Check out the easy things first.

Have a good look and pry on the universal joints.

Randy

Yes, check all the drive line for play. I usually find that vibrations when letting off the gas are due to something being loose. Common source is a loose pinion or t-case flange or a slip yoke that is out of grease or pulled out to far that it is loose. Could also be u-joints. Basically the checking is all the same, climb under the truck and then just grab each part of the drive shaft and give it a tug and feel for any play up-down or side-side. You want to have it out of gear so things are free to move. And you an also unbolt the shaft at either end and feel the u-joint motion by hand as some times the joints get loose as they wear but they may also feel too tight and bind up as they rotate.

Could I also try removing the whole rear drive shaft & drive in front wheel drive to try pinpointing the noise/vibration source?

It surely feels like it's coming from near my right foot pedal.

I soon have to drive/move to Saskatoon in April, I wonder if it will make it there if I can't fix this problem in time... <img src="/forums/images/graemlins/rolleyes.gif" alt="" />

A while a go I too had a clunk somewhere in my drive line of my 91 Toyota. I hunted around for loose components and never ended up finding it until I made the swap from my standard 4:10 differentials to 4.56. After I replaced the rear diff, the gears where still good but there was a lot of play in the carrier bearings holding the ring gear. The noise I had was an irregular "warbling" when going +120km/hr with neutral gas. If I let up or put gas down, the noise would go away. That source of the noise was hard to pin down. I also had drive line clunk/bang when I when I threw the truck into reverse in the mornings when first going to work. When it was getting bad I had to use a bit gas to "break" the rear into position, as the ring gear was so loose that it was binding up between the ring and pinion gear. That noise sounded like it was coming from the transmission but since it was fine going forward I started contemplating a transmission swap. Both noises when away after swapping differentials. At that time the truck had about ~450,000kms on it. If all else fails it might be the rear end.

IIRC, you've got an xcab don't you?

I'd give that carrier bearing and the ujoints a good physical inspection. DO NOT OVERTHINK THIS. You've got a lot of miles on the ol gal; if you haven't worked over the ujoints since you've had the truck, it might be time. Start with the basics, as oldsub suggests.

The carrier bearings are $$$ and sometimes hard to find. The workaround for that is to take it out of the equation, and have a longer one piece DL fabbed up. This wouldn't be the first time it's been done.

Check your transfer case too. I had the same sound in a Jeep Cherokee and the drive chain was jumping the gears in the transfer. <img src="/forums/images/graemlins/kewl.gif" alt="" />

Ok,

Last weekend, I hand-checked the drive shaft & noticed that the pinion at the differential could be rotated about 1/4" freely, while truck was parked in gear. Since then, I parked the truck as-is & went back to work in Vancouver.

Yesterday (Friday), my gf used the truck & the noise/vibration continued and got worse. The sound began as soon as she started driving and progressively got worse.
It sounded like a wrench banging on a metal pipe. The more gas she put, the faster & louder it got. As it became worse, it got louder with a stronger vibration.

On the way home, at a yield stop, after she put it in 1st & let off the clutch very gently, the whole truck shook violently upon acceleration.

She clutched in a second time and kept adding gas until the truck got going. Banging noise & shaking continued.

At the next intersection (before calling the tow truck), she experienced the big bang and shaking again, but the truck wouldn't go forward. She tried again & the truck was just revving with the gear engaged. She then gravity backed-up onto half of someone's driveway and reversed the latter half of driveway. No noise/vibration was observed when backing up.

Today:

I just traced down (visually) some slipping action at the pinion/driveshaft. I really hope this is just my pinion/rear 3rd causing all these problems & not anything else? <img src="/forums/images/graemlins/cyclops.gif" alt="" /> Thanks!

FYI: My current rear 3rd is a 94' V6 Auto 4.88 modified with 87 Supra LSD.

All right, I got right into it today!

I just finished pulling the rear 3rd out. And guess what? Broken tooth, loose pinion, metal shaving at the magnetic plug. See pics.

I hope this is my only problem! I'm going to replace my rear 3rd with the easiest/quickest method. That is to find another junkyard/used 94 v6 auto 4.88 3rd and drop into my existing 91 rear axle housing.

If I were to rebuilt my existing 3rd, would it be safe to re-use any of the existing components such as supra LSD, supra carrier bearing & outer race, (except new ring, pinion, and V6 bearing kit?)

Thanks,

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