Inferno451

Thanks guys! Magnusian, all clips and pins are installed as per FSM. Problem solved. For now

YotaFreakTN

what solved the problem?

Inferno451

Ok, so i posted this a couple days ago, but i'm not sure what happened to it. I'm having this terrible grinding noise that is worrying me a bit. The previous owner told me this happens every once in a while and after about 15k miles of ownership i finally experienced it. When slowing down in 3rd gear (not sure if that matters or not) i got this horrible, horrible grinding noise that seemed to be coming from the front or middle of the truck. Didn't change when i shifted gears or pushed in the clutch, but if i put my foot on the gas even just a TEENY bit, just enough to take up the slack in the cable, it went away. It did go away when i gave it gas, but even if i just took out the slack without revving it, it still made it stop. It grinded until i got down to about 5 miles per hour, then there was a lound CLUNK and it went away. This has happened randomly 3 times in the last week. Any ideas? It sounds expensive. BTW it's a 1992 pickup, 215,000 miles, 4x4, v6, plenty of fluid in everything, and the previous owner had the dealership check out and service the entire front end, and i believe new cv joints. Thanks guys!

iamsuperbleeder

well I can tell you what more than likely happened to your previous thread read this


sounds like the spindle bushings; VERY common

search it, and you'll find tons of info on them

yoterr

my u joints did that, only under deceleration it grinded n such bit did it all the time...so ide go with bleeders idear

Inferno451

K guys, thanks a lot. I'll give the spindle bushings a try. I searched around and read a lot about it, but a few things seemed different in my case. I pickup up the materials to lube the spindle bushings yesterday, so i'll give it a try.

desertgoose

This is a complete long shot (and only applies if you have an ADD Front Diff) but I too had the exact same symptoms in the exact same truck about 10 - 12 years ago. After many return trips to the dealer after an HG replacement (they actually warrantied a fulll long block) it was determined the vacuum lines to the ADD motor were not routed correctly and in fact for several months the truck was in 4x4/front axle engaged with the lever in 2Hi. The deceleration changed the vacuum characteristics and the truck was actually trying to "get out" of 4x4 on it's own. I spoke with the mechanic who figured this all out on a hunch...he started the truck in neutral with the 4x4 lever in 2Hi. He pushed the truck across the lot while looking under the truck and saw the driveshaft moving..from there he traced and re-routed all the vacuum lines correctly. I have put another 100K on the truck since that time and have never had the problem again. As an FYI I am the original and still owner of this truck, so I have a complete history with it.

Again, I know it is a long shot but your symptoms bring up bad memories of that painful grinding sound with the big clunk at the end.

Good luck

Inferno451

Weeeeellllllllllllllll, it actually went away for a couple days and is now back. I did the spindle lubrication thing just to be safe, but it made absolutely no difference. I'm thinking it has to be either a sticking caliper piston making the pad drag or just rotors with a bad surface. I can't take my truck apart to have the rotors turned right now, but i'll let you guys know what finally fixes it.

Inferno451

Desertgoose, i'll give that a shot. I did the spindle bushing lube thing and it made no difference, there was plenty of grease inside. The PO must have already done it. Very thoughtful. But correct me if i'm wrong, but wouldn't the front driveshaft spin anyway even in 2 hi? Since i have the ADD system that doesn't unlock the front drive system, isn't the only place it stops spinning the transfer case? Maybe i'm completely wrong about this.

dropzone

iTrader: (6)

yes you are correct, with ADD the front shaft still spins...but did you check the rear driveshaft? similar sound on mine right before my rear DS felt out of the truck...there was one bolt left hanging in the flange...

hunter4runner

did you ever seat the brake pads ?

got to 30 mph then stop as fast as possiable X2
then do 40
then 50
then if the sound is still then keep doing 30 to 0 about 6 more times that should do it

thook

^^^^ Good point.......

Inferno451

All front and rear driveshaft bolts present and accounted for, all tight and all joints well greased. Any other ideas, guys?

desertgoose

Just back in town...my driveshaft does not spin in 2-Hi. Did you have any work done on your truck just prior to the problem starting? Perhaps check vacuum lines of the ADD?

Good luck I,ll be curious as to what you find

Inferno451

K, not sure if anybody's still looking at this post, but i figured it out! After some tracing, some head scratching and a LOT of thinking and looking at diagrams, i figured out that the PO had switched around some wires. The blue and red plugs for the ADD Vacuum switching valves had been put on the identical blue and red plugs about 6 inches away for the emissions control systems. That meant that first of all, the emissions systems have not been working correctly for probably the last 100k miles, but more importantly, the VSV for locking the front differential gears together had been getting constant voltage and under certain conditions the VSV for unlocking the diff had been getting voltage at the same time! That's right, the front differential was trying to lock and unlock AT THE SAME TIME! The grinding was caused by the sliding sleeve inside the differential being stuck in the middle of locked and unlocked and grinding on the teeth inside. Plugs switched, problem solved. 4x4 Now works like a charm and the weird screeching noise i had is now solved too!

Inferno451

Finally solved it! Turns out it was the front differential. I ended up putting my truck up on stands and running it to be able to trace where the noise was coming from. Definitely the differential. Did some research and saw that the front driveshaft should not be turning in 2 wheel drive, which it did if i spun either one of the wheels with my hand. I figured this might have been related to a horrible grinding noise i was intermittently experiencing when decelerating. After some tracing, some head scratching and a LOT of thinking and looking at diagrams, i figured out that the PO had switched around some wires. The blue and red plugs for the ADD Vacuum switching valves had been switched around with the identical blue and red plugs for the emissions systems about 6 inches away. That meant that first of all, the emissions systems have not been working correctly for probably the last 100k miles, but more importantly, the VSV for locking the front differential gears together had been getting constant voltage and under certain conditions the VSV for unlocking the diff had been getting voltage at the same time! That's right, the front differential was trying to lock and unlock AT THE SAME TIME! The grinding was caused by the sliding sleeve inside the differential being stuck in the middle of locked and unlocked and grinding on the teeth inside. Plugs switched, problem solved. 4x4 Now works like a charm and the weird screeching noise i had is now solved too!