Guess the noise... 1992 FJ80 metal scraping sound from front end upon acceleration. (1 Viewer)

[tsuggett]

1992 FJ80 216,xxx miles. 2.5 OME lift

About 6 months ago I did some light off-roading, and the next day I heard a slight metal scraping sound from the front end when I was leaving house. It only happened at low speeds when accelerating and went away when I let off the gas (I have never heard it when going in reverse or neutral). I was assuming something may have gotten bent. I checked the brakes, drive shaft, etc. to see if anything was rubbing, and didn't notice anything out of the ordinary. I took the front wheels off to inspect the brakes and replaced the front brake pads just in case. Also changed out the front diff, tcase, and rear diff fluids and didn't notice anything bad (metal shavings). The noise lasted for another day or two, then completely went away...

It just came back much louder this last weekend on a ski trip when I had a full carload of people, gear, and about 2-3 feet of snow on top of the car. This time it was almost every time I accelerated at low speeds/gears, and the sound would react with how much gas I was giving it. Seems to be fully related to RPMs. I attached a link to a video that I was able to get with the noise this weekend. I noticed the sound would even happen when I was in high gears going faster when I would hit a bump in the road. Does this sound like something is rubbing on the driveline like the exhaust or something? I'm really hoping this isn't a tcase or transmission issue, but any ideas would help!!



Also for reference, I did have an issue with the spindle bushing a few years back and fixed that. This sound is completely different from what I was experiencing with that.

Cheers!!
Tyler

 

[BILT4ME]

1992 FJ80 216,xxx miles. 2.5 OME lift

About 6 months ago I did some light off-roading, and the next day I heard a slight metal scraping sound from the front end when I was leaving house. It only happened at low speeds when accelerating and went away when I let off the gas (I have never heard it when going in reverse or neutral). I was assuming something may have gotten bent. I checked the brakes, drive shaft, etc. to see if anything was rubbing, and didn't notice anything out of the ordinary. I took the front wheels off to inspect the brakes and replaced the front brake pads just in case. Also changed out the front diff, tcase, and rear diff fluids and didn't notice anything bad (metal shavings). The noise lasted for another day or two, then completely went away...

It just came back much louder this last weekend on a ski trip when I had a full carload of people, gear, and about 2-3 feet of snow on top of the car. This time it was almost every time I accelerated at low speeds/gears, and the sound would react with how much gas I was giving it. Seems to be fully related to RPMs. I attached a link to a video that I was able to get with the noise this weekend. I noticed the sound would even happen when I was in high gears going faster when I would hit a bump in the road. Does this sound like something is rubbing on the driveline like the exhaust or something? I'm really hoping this isn't a tcase or transmission issue, but any ideas would help!!



Also for reference, I did have an issue with the spindle bushing a few years back and fixed that. This sound is completely different from what I was experiencing with that.

Cheers!!
Tyler

At first I thought that was engine RPM related, but it is not the same RPM as the engine.

I would say that is engine torque related against the driveline or movement on the engine.

1) U-joints
2) Broken motor mount allowing the driveline to shift and contact something
3) Loose wheel bearings causing a brake pad to drag and make noise

 

[tsuggett]

At first I thought that was engine RPM related, but it is not the same RPM as the engine.

I would say that is engine torque related against the driveline or movement on the engine.

1) U-joints
2) Broken motor mount allowing the driveline to shift and contact something
3) Loose wheel bearings causing a brake pad to drag and make noise

BILT4ME​

Thank you for the info here! It definitely seems to be engine torque related. I will be crawling under and inspecting the u-joints, motor mounts later today. One thing I forgot to add earlier, is that one of the front sway bar bushings is bulging, I already have the new bushings I've been meaning to install. This may be a dumb question, but could that possibly be a cause of the driveline touching something when the engine is torquing?

 

[BILT4ME]

Sway bar should have no effect on this. That would cause a clunking sound, but will not affect twist or anything that should allow a rotating part to come in contact with something else.

Whatever the noise, it is consistent with rolling speed, so it could be:
Wheel
Axle
Driveshaft
Brakes
wheel bearing
Hubs

 

[ajax1]

Is brake shield rubbing or have rocks and grasshoppers in it?

 

[tsuggett]

Sway bar should have no effect on this. That would cause a clunking sound, but will not affect twist or anything that should allow a rotating part to come in contact with something else.

Whatever the noise, it is consistent with rolling speed, so it could be:
Wheel
Axle
Driveshaft
Brakes
wheel bearing
Hubs

Definitely makes sense about the sway bar not having any effect on this sound. Was sick this past week so wasn't able to crawl under it but will be inspecting everything it this week, will keep you posted with findings! Thanks again for the help.

 

[tsuggett]

Is brake shield rubbing or have rocks and grasshoppers in it?

Going to take it to my buddy's garage this week and going to pull the front wheels off and will be deeply inspecting the brakes. Had a similar sound on my tundra a long time ago that ended up being a tiny piece of metal lodged in the brakes. When I replaced the brake pads on the FJ80 months ago, I didn't see anything, but going to be looking again more thoroughly. Will report back!

 

[tsuggett]

SOLVED! Spent hours looking around for any signs of scraping, checked the u-joints, engine and transmission mount, and pulled apart the brakes. Went back under one last time with a clear head and found the culprit. There is a little plate on the back of the tcase where the rear drive shaft connects, and it looked a little off. I noticed the bolts attaching the rear drive shaft had fresh TINY scratch marks where it looked like it had grinding against the plate (pics attached). It had a few tiny rocks in between the plate and t-case, so I got those out with a flathead and carefully pried the plate back flush against the t-case. I'm guessing it was knocked loose when I was off roading or maybe just over time it started popping out. This would make sense why this was torque related I think and it would barely rub that plate and DS together. Also makes sense on why it sounded like something scraping against a circular plate. Hopefully this helps someone in the future. Cheers, and thanks for the help!