Rear End noise

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, Skimlinks, and others.

1962fj40

1962fj40

10 Year 15 Year 20 Year
Joined
Jul 1, 2004
Threads
105
Messages
468
Location
Phoenix, AZ
Website
fj40bugcatcher.dyndns.org
Now that I'm getting things running good, I decided to take it out today and noticed it had a really bad metal-ish noise coming from the rear end. I decided to lift up the rear end and take some videos with it idling and first gear. The driver side tire is turning but the passenger side looks like it wants to turn, but is vibrating a lot and if I try to turn it by hand where they're running or not is very hard to turn. Before I take this apart does anyone have any suggestions?

Dropbox

www.dropbox.com www.dropbox.com

Just a note, if Dropbox ask you to install the app don't you can just do it in the browser without downloading anything

Robert
 
Last edited:
Its hard to tell. Pull the wheels and drums. I could be just rusty drums or shoes hanging up. 1 tire spinning is typical of an open differential
 
Sounds like gears with chunks missing to me. Drain the oil and fish around in there with magnet on a wire, use a bore scope if you got one. <$50 for new oil
 
As soon as that oil comes out you’ll have a very good idea of what happened. If it’s clean, the differential is likely ok. If it’s full of metal glitter, pull the cover and figure out what got chewed up
 
What everyone here is telling you is good.
Brakes "might" be too tight on your passenger rear not allowing it to turn freely.

Also, check your drive shafts. Make sure none of the bolts are loose. I've experience "clunking" noise due to a couple bolts becoming loose. And wiggle the drive shafts at the ends to see if there is any slop/play at your u-joints. Ussualy, they make more noise at higher rpm, but you never know.

Maybe you have play on the rear pinion and the nut isn't torqued down? That would lead to damage for the dif either way.

I would check the diff oil last once you rule everything else out. Mine was nice and full of metal glitter. I could still drive but there was an obvious "scraping" noise. For me, it made me think of brake pads being slightly scraped upon for every revolution of the tires. Not very loud, but it became more obvious upon accelerattion. Hard to tell from your video.

In the end, mine turned out to be a bad diff. Let us know what you find
 
Last edited:
I finally got everything looked at and I did discover the brakes were over adjusted, but nothing going on with the differential. When I put in a higher gear the noise will get really bad and it seems like it's something coming from the transfer case or transmission or even possibly drive shaft. Whatever is causing all the noise and vibrations, the faster I go the worse the noise and vibrations get. I think I'm going to take the rear drive shaft off and see if the noise will go away.
 
Edit: what year is your Fj40? Even if it doesn't have the pto gear, I know the later style t-case had the gear spacer. I think you can still engage the "pto" and let it run in neutral just to get the gears inside the t-case moving. Not 100% sure though.
-----------------------------------
You can do a couple of things. Easiest one is this. Leave drive shafts on. put you're t-case in neutral. Put transmission in neutral. Turn on your Fj40. This will engage the PTO gears and begin moving things inside.

Now shift your transmission. Clutch in and shift through your transmission gears. 1st, 2nd, 3rd, 4th, etc. You can let go of the clutch pedal for every gear, it won't kill or shut off your Fj40. Just accelerate lightly to see if you hear anything. don't go very fast with the gears. It's running off the PTO gears, which i belive is meant for slow operations. Your rear drive shaft won't be spinning nor your front. Just mainly the t-case and transmission from what I understand. But it'll be under a light load.


For further troubleshooting, you can take the Rear drive shaft off. Put wheel stops on your front tires. Leave your front locking hubs UNLOCKED. Raise up your rear end on jack stands at the axle/diff. Jump inside your Fj40, turn it on, and shift through all the gears as if you're diving normally. You can accelerate the vehicle to 40+ mph. I've done it testing this exact way. Did the noise go away? Is the sound still there?

If it went away, then it's either your rear drive shaft or rear diff. If the sound is there, then it's either you t-case or transmission.
 
Living in the Past said:
Being a 1962 FJ40 should say if it's still the original transmission, transfer case and centered diff rear axle. Believe we met at the southeast corner of 35th AVE and Greenway? That was a long time ago since I moved out of Phoenix over eighteen years ago.
Click to expand...
Yeah that was me, if I recall correctly you drove up in your FJ45?

1962 FJ40
Original F engine (48,000 miles)
SM420 Tranny
Toyota TC

Robert
 
DesertFJ40 said:
Edit: what year is your Fj40? Even if it doesn't have the pto gear, I know the later style t-case had the gear spacer. I think you can still engage the "pto" and let it run in neutral just to get the gears inside the t-case moving. Not 100% sure though.
-----------------------------------
You can do a couple of things. Easiest one is this. Leave drive shafts on. put you're t-case in neutral. Put transmission in neutral. Turn on your Fj40. This will engage the PTO gears and begin moving things inside.

Now shift your transmission. Clutch in and shift through your transmission gears. 1st, 2nd, 3rd, 4th, etc. You can let go of the clutch pedal for every gear, it won't kill or shut off your Fj40. Just accelerate lightly to see if you hear anything. don't go very fast with the gears. It's running off the PTO gears, which i belive is meant for slow operations. Your rear drive shaft won't be spinning nor your front. Just mainly the t-case and transmission from what I understand. But it'll be under a light load.


For further troubleshooting, you can take the Rear drive shaft off. Put wheel stops on your front tires. Leave your front locking hubs UNLOCKED. Raise up your rear end on jack stands at the axle/diff. Jump inside your Fj40, turn it on, and shift through all the gears as if you're diving normally. You can accelerate the vehicle to 40+ mph. I've done it testing this exact way. Did the noise go away? Is the sound still there?

If it went away, then it's either your rear drive shaft or rear diff. If the sound is there, then it's either you t-case or transmission.
Click to expand...
1962 1F, SM420 Tranny with Toyota TC. I'm thinking that the SM420 has a similar PTO access cover so running through the years as he described with the transfer case of neutral should still be a applicable?
 
1962fj40 said:
Yeah that was me, if I recall correctly you drove up in your FJ45?

1962 FJ40
Original F engine (48,000 miles)
SM420 Tranny
Toyota TC

Robert
Click to expand...

As I remember the attachment of the early transfer to the early transmission was different than later T/T. Guessing the plate for the SM420 would be different as well. Early transfer case used four bolts for the cover on the back. Later uses six bolts.
 
If you’ve got an SM420 conversion that’ll complicate things. I’ve run one for 24 years, super stout, great low end gearing but the 3/4” plate adapters that were generally used to mount the stock transfer case can be problematic. It’s possible the main retention nut has started to back off, been a long time but I think my friend damaged several transmissions that way.

I’d run it as others have suggested, very securely up on jackstands with the rear end lifted and the rear driveshaft connected
 
Today I did verify the rear differential is fine, drained and pulled the cover and it looks brand new. I also disconnect to the Driveline and ran through the gears with no issues noise or vibrations. So I guess that just leaves the drive shaft. Looking at it I see nothing wrong with it, but I did notice a good amount of free play in the slip joint.
 
You must log in or register to reply here.

Share this page

Back
Top Bottom