FJ62 Rear Drive Line Noise (1 Viewer)

[poptart]

Since, I've bought my FJ62, I've had a bad drive line noise coming from the rear. I've slowly have been fixing and replacing stuff and still have the noise. It's gotten better now because don't really here anything at lower speeds any more. I think the new tires helped with that, old ones had plenty of tread left, but were rock hard from age. So now this loud hum begins somewhere around 57-60mph. It kind of sounds like when bearings are going bad. But I've replaced the axle bearings and no luck. I should probably just go ahead and list everything I've done since I've start working on the '62 last year.

Drive Shafts have new U joints and were rebalanced
Drum Brakes have been rebuilt with new drums, new drums were turned (out of spec ovals when new )
New tires, 31" BFG Ko2's.
Replaced axle bearings and seals with kit from Cruiser Outfitters (P/N: RAK7395SF).
Just had the tires rebalanced and that helped with some of the noise (guessing the first shop didn't do a very good which is concerning because they balanced my driveshafts and installed the new u-joints )

I'm guessing next step is rebuilding the diff, unless any ones has any other ideas.

 

[franklin40]

check the diff fluid. it’ll tell you if there are metal shavings or not which will give you a good idea if there’s something bad in the diff. you could also just pull the rear cover off and look. you should likely change the fluid anyway

 

[poptart]

check the diff fluid. it’ll tell you if there are metal shavings or not which will give you a good idea if there’s something bad in the diff. you could also just pull the rear cover off and look. you should likely change the fluid anyway

Oh I should have put that in there. I changed the fluid when I first got it and then new fluid when I did the rear axle bearings. Used Lucas 80w90 both times. Looked clean.

 

[OSS]

A lazy way to rule out worn gears in the differential is to drain it and fill with 140 weight gear oil (yes it's safe) then drive it.

If the noise diminishes and stuff sounds better back there, the noise is worn gears or bearings in the diff.
Worn gears usually whine.

After the test is done, replace the oil with 80w-90 (for winter time).

 

[TheNeek]

I had a noise I couldn't track down either. Finally brought it to a local driveline shop. It was the input shaft bearing on the rear differential. Had it rebuilt. Air locker is optional in your case. I don't have any fancy troubleshooting techniques for the internal bearings though.

 

[poptart]

I had a noise I couldn't track down either. Finally brought it to a local driveline shop. It was the input shaft bearing on the rear differential. Had it rebuilt. Air locker is optional in your case. I don't have any fancy troubleshooting techniques for the internal bearings though.

Trust me, air locker has crossed my mind lol, but don't have the coin for that right now. I think I'll just replace all the bearings at this point.

 

[dbleon]

Tcase output .. check for play. Mine has some play and same symptoms. Time for a rebuild before too long for me

 

[poptart]

Welp, go figure. The shop that I had put in my U joints and balance my drive shafts didn’t grease them. They also didn’t install the u joints correctly so I can’t get to the zerk fittings without disconnecting one side of the drive shaft and moving them around.
Haven’t been around to drive my FJ62 for a bit but finally got around to driving it around today the rumble/growl/hum pretty much seems to be gone. Didn’t get on the highway but was above 60mhp in so spots.

I guess I should have checked the u joints before installing the driveshafts, but I probably got excited and threw them on. And that the last time I’ll be using that shop for anything. Which is crazy because my mechanic recommended them.

 

[Spook50]

A lazy way to rule out worn gears in the differential is to drain it and fill with 140 weight gear oil (yes it's safe) then drive it.

If the noise diminishes and stuff sounds better back there, the noise is worn gears or bearings in the diff.
Worn gears usually whine.

After the test is done, replace the oil with 80w-90 (for winter time).

Any thoughts on an occasional rumble/growl? This is entirely separate from my 4HI noise, but if I accelerate hard, brake hard, or accelerate around a corner I've noticed in the last few months a deep kind of rumble sound.

 

[poptart]

Any thoughts on an occasional rumble/growl? This is entirely separate from my 4HI noise, but if I accelerate hard, brake hard, or accelerate around a corner I've noticed in the last few months a deep kind of rumble sound.

Is it coming from the rear? If it’s happening around cornering I’d start with outer axle bearings. Might be that they’re on their way out, and the shifts in loads are effecting them. That’s just my first thought because you mentioned cornering but really you can apply that to a lot of issues, so...

 

[Spook50]

Is it coming from the rear? If it’s happening around cornering I’d start with outer axle bearings. Might be that they’re on their way out, and the shifts in loads are effecting them. That’s just my first thought because you mentioned cornering but really you can apply that to a lot of issues, so...

They've never been changed, so it's entirely possible. On the list to look at em.