Clunking in rear end in reverse (1 Viewer)

[TexYoung]

1973 stock FJ40. I am getting a clunking noise coming from the rear diff when in reverse. No issue at all going forward. I put it up on jackstands and ran it in reverse and I guess because there was no weight on the axle it didn't make the noise. I drained and replaced the diff fluid and replaced the u-joints less than 5K and 1 year ago and they look fine. All drive shaft bolts are tight. I have not pulled the diff cover yet. Any suggestions? Thanks all!

 

[bikersmurf]

Pinion gear missing a chunk if it does if repeatedly.

Mine did it in forward and reverse. Can’t remove the cover on a FF so I had to pull the 3rd to find the missing chunk.

 

[TexYoung]

Never really worked on a rear diff. My Haynes manual doesn't show how to tear it down. Is there a resource somewhere I can use for assistance?

 

[Bama4door]

Never really worked on a rear diff. My Haynes manual doesn't show how to tear it down. Is there a resource somewhere I can use for assistance?

Jack up rear axle so tires are off ground. Remove rear diff cover. Remove side bolt that holds center pin in, then remove center pin out of diff. Move each tire in slightly to take pressure off C clips, then remove both C clips. Slide tires/axles out of diff.

At this point, you can either take out the whole rear 3rd member or remove the spider gears to try and inspect the pinion. To remove rear 3rd member, disconnect rear driveshaft and then remove 10 bolts around axle housing and then pull out rear 3rd member out.

 

[TexYoung]

Sounds like a good starting point. I just went through this thread Diff Rebuild Walk-through - '81 with 4.11s and New Rear ARB Locker Looks like a rebuild is a bit over my head. Looks like some special tools are required. I may do the inspection as mentioned, but I may have to bow out to a mechanic if a rebuild is needed,

 

[shelfboy1]

did you check the play up and down could be a loose pinion nut

 

[rrv333]

Dajda's Do Rite in North Richland Hills is a LC shop. The owner rebuilt the rear diff on my 40. Great guy to boot.
817-427-4857 ask for Mike the owner.

 

[bikersmurf]

Check the pinion nut first.

Pulling the diff is straight forward. If it needs work, bring it to a shop and have them fix it... or swap in another and call it a day. Worst case, if you’re stuck swap in your front and call it a day.

 

[TexYoung]

Dajda's Do Rite in North Richland Hills is a LC shop. The owner rebuilt the rear diff on my 40. Great guy to boot.
817-427-4857 ask for Mike the owner.

I have used Mike before. Does great work.

 

[TexYoung]

Check the pinion nut first.

Pulling the diff is straight forward. If it needs work, bring it to a shop and have them fix it... or swap in another and call it a day. Worst case, if you’re stuck swap in your front and call it a day.

Ya, I think I can pull it. Where can you get a good swap diff?

 

[TexYoung]

did you check the play up and down could be a loose pinion nut

Will pull cover off next week after Thanksgiving and take a look at the pinion nut, etc.

 

[scoutingranch]

I always take my differentials to the pros. I don't do differentials and those guys don't weld on live natural gas lines.

 

[GA Architect]

I always take my differentials to the pros. I don't do differentials and those guys don't weld on live natural gas lines.

Yep, last Summer I installed a set of 3.70's built & set-up by Georg, @orangefj45

 

[TexYoung]

did you check the play up and down could be a loose pinion nut

As mentioned, I know very little about rear diffs. I took the rear cover off. Where is the pinion nut located? I see the center pin and it seems to have some play, not sure if that is normal. I dont see any teeth ,missing on the gears, no ground metal in the bottom.

 

[middlecalf]

Pinion yoke is what the drive shaft bolts to, and the pinion nut is what holds the yoke onto the differential input shaft (or whatever that’s caled). If you have a loose pinion nut the yoke will wobble up/down/around rather than just spin on axis.

 

[Simcoe]

 

[Simcoe]

Drop your rear driveshaft and you will be staring right at the pinion nut

 

[TexYoung]

Pinion yoke is what the drive shaft bolts to, and the pinion nut is what holds the yoke onto the differential input shaft (or whatever that’s caled). If you have a loose pinion nut the yoke will wobble up/down/around rather than just spin on axis.

Thanks, I will check that. I dont have any play there though.

 

[drnekFJ40]

Get the book Toyota land cruiser chassis & body service manual...there is a lot of great info about how to service your LC..

 

[DSRTRDR]

why go reverse ?

"Toyota - moving forward" - granted, that was the old slogan, but then, we drive old Toyotas