R150f and 8" diff seems to have excessive backlash

[Jgrov2]

I'm running a R150f behind a Toyota 3uz-fe in a 96 dual cab pickup with Toyota 8" diff. Just had the diff lapped and check and it's all in spec but it still seems to clunk on and off the gas. The gearbox is used and probably a bit flogged out, I'm still using the two piece tail shaft as well. Should I start looking at rebuilding the box or could my issue lie further forward such clutch or input shaft?

 

[Aisin]

It’s hard for us to diagnose your truck through a computer screen. It’s not hard to figure what needs fixed. You just have to climb underneath it and look at.

 

[Clb]

Ever drive a vehicle with + 200k on it?
What have you done as to diagnosis?
Did that U joint cap finally fail?
Details will help, but go to driveline first!
wtf is differential "lapping" and who sold it to ya?

 

[vikingsven]

Could be slop in the drive line slip as well.

 

[Wulf]

Could be slop in the drive line slip as well.

Yeah, that's probably worth pulling apart and greasing.


is the drive shaft carrier bearing still in place? check it for slop

​​​​​​What leaves are you running? if you have a ton of axle wrap it'll probably be clunky

 

[Jgrov2]

Ever drive a vehicle with + 200k on it?
What have you done as to diagnosis?
Did that U joint cap finally fail?
Details will help, but go to driveline first!
wtf is differential "lapping" and who sold it to ya?

Haven’t driven one with that many miles hence me asking. Diagnosis was my kidneys rattling round inside me everytime it got on and off the power. I did twist the drive shaft while stationary and it would turn 1/4 turn but the pinion bearing was rooted so I got that replaced and the others checked. Diff lapping is running the gear and pinion in the correct place with grinding compound the mesh the teeth as correctly as possible I’m sure there’s plenty of info and videos if you wanna have a look.

also I pulled the shaft and cleaned and greased it seems like no play in it at all u joints good as well. Carrier bearing was shot which I assumed caused the pinion bearing to blowout or vice versa. It’s got 3inch leafs from Aussie company efs. They are horrid and pretty stiff so I don’t think it’s axle wrap especially as I can feel it coasting and getting on the gas.

since having the diff tidied up the driveshaft hardly moves at all when I try turning it by hand stationary. I’m guessing I’ve fixed up the slop in the diff but there must be a bit in the gearbox. Just trying to convince myself before I pull the gearbox and rebuild it. I’d hate to do it and there be no change.

the rear drive shaft angle must be a bit off due to the 3 inch lift because I’ve blow two carrier bearings in the space of 25000kms I’ve tried spacing the mount down but it seems to almost feel like it’s a bit bouncy and made no difference to the backlash I’m feeling

 

[Clb]

I DOUBT IT
entering an abrasive into a diff that is already shot will fix it?????
fubar

someone back me up???

no way the pinion bearing was the ONLY FUKT UP bearing in the diff!

1/4 turn of slop in the d.l. is backlash!

 

[Jgrov2]

I DOUBT IT
entering an abrasive into a diff that is already shot will fix it?????
fubar

someone back me up???

no way the pinion bearing was the ONLY FUKT UP bearing in the diff!

1/4 turn of slop in the d.l. is backlash!

The diff wasn't fubar and I recently installed an air diff locker so I put new side bearings in just didnt have time to or the bearings to do the pinion as I need the car and couldnt stand the detroit locker anymore. Here's a link for more info on gear lapping, https://www.geartechnology.com/issues/0908x/masseth.pdf, it was just done to hone it a bit better while they had it apart redoing the pinion.

 

[Jgrov2]

Just a thought I had to try and isolate it, If i pull the rear driveshaft out and drive just using the front wheel to see if I experience the same amount of backlash or shockload, that would narrow it down to driveshaft or gearbox correct?

 

[Clb]

Time to cruize over to expidition portal!?

 

[I Lean]

It is HIGHLY doubtful they did any gear lapping. That's something you would do when manufacturing the gears, not while installed in the diff. They may have tightened up the backlash or something like that, painted it with marking compound and fleeced you by telling you that was "lapping".

 

[Clb]

Just a thought I had to try and isolate it, If i pull the rear driveshaft out and drive just using the front wheel to see if I experience the same amount of backlash or shockload, that would narrow it down to driveshaft or gearbox correct?

Kicking it in neutral does the same thing.
If you are bored, drop the rear flange.
Grab pinion yolk and twist.
How many degrees of twist?

 

[Jgrov2]

It is HIGHLY doubtful they did any gear lapping. That's something you would do when manufacturing the gears, not while installed in the diff. They may have tightened up the backlash or something like that, painted it with marking compound and fleeced you by telling you that was "lapping".

Y’all getting caught up on the lapping, he did It and I saw it as I wanted to check it out and know the guy. He did the lapping mostly because he had it and it has 450,000kms on it not because of the backlash issue. He had it to make a new solid pinion spacer and install the pinion bearings.

ill give the back flange a twist if I get some time this weekend but as a development I’ve notice the amount of backlash is proportional to what gear I’m in Eg it’s the worst in 1st and almost negligible in 4th.