Backlash - how much is normal and how to check?

[Jitterbug]

I have recently fitted new (used) complete diffs to my '84 90 and there is a fair amount of what i think is backlash.

It comes in the form of a 'clunk' or sometime double 'clunk' when the drivetrain goes from load to no load and the other way. If i am careful i can eliminate it by carefully matching engine speed to wheel speed when changing gear (which i know i should alway do).

There is some rotational play at the input flange but from what i can tell no more than the diffs they replaced (which didnt have this problem).

Where should i be looking to identify the source of this or is it likely the sum of several tollerances?

Cheers for the help. Starting to feel a bit defeated by the list of things i need to sort at the moment!

[omnibus]

in my limited knowledge backlash is quite a fine ajdustment too much is bad too little is worse, i adjusted mine out of the same concern as you and when i got RWC i asked the mechanic about what i had done and he didnt say a word he just shook his head. so i went home and borrowed a mates meter and checked lucky for me I actually jagged it by feel but i dont recommend doin it that way, if you have a salsbury on back i would think it shouldn't be too bad as the adjustment could be done from the rear with the diff still in, with diff in the front it will be take axles out and remove centre and adjust on bench. Now getting your hands on the micrometer. this is very short look at what u do.

hope the pics help, you can see where he adjusts the backlash and where to put ur meter on check your book for specs they probly same anyway (they are rangie diffs but better to be safe


well the video didnt work so sorry no pics but if u are keen it is called a 4x4 is born part 4 at around 10mins 30 secs onwards he does a quik flash over backlash adjust it isn't long but u can see where he takes measurement and where he adjust the bearings.

If you need a hand pm me i will give you my number as i am on the sunny coast and can head to brisvegas to help ya if needed

[Reads90]

You sure it's the diffs and not bushes as worn bushes will give a clunk and very difficult to tell where the sound is coming from.



I would check these before you start ripping apart diffs again

Ali

[Blknight.aus]

when I get back from TSV I might be able to clear you an evening slot.

we can scope the chassis out and I'll show you how to check the most common offenders for lash.

[Jitterbug]

Cheers guys, I will tripple check everything is fully torqued and the condition of the bushes. I replaced most of the buses, front and rear radius arms and panhard rod but will have a good look around.
Blknight, i am away with work 3nights a week but thurs, fri night or weekends are fine. The car is on the road so i can come to you if it makes things easier?

[isuzutoo-eh]

Crawl underneath while someone else rocks the Landy side to side then front to back and watch all the suspension bushes do their thing-radius arms, panhard rod, trailing arms and A frame. That'll tell you if the knock is from bushes or it is actually backlash or slop in the drivetrain somewhere.

[goingbush]

well the video didnt work so sorry no pics but if u are keen it is called a 4x4 is born part 4 at around 10mins 30 secs onwards he does a quik flash over backlash adjust it isn't long but u can see where he takes measurement and where he adjust the bearings.


heres that video A 4x4 is Born part 4 - YouTube
the bit in question is at 10.30

pity he dosent use bearing blue to check the contact pattern,

[goingbush]

I have recently fitted new (used) complete diffs to my '84 90 and there is a fair amount of what i think is backlash.

It comes in the form of a 'clunk' or sometime double 'clunk' when the drivetrain goes from load to no load and the other way. If i am careful i can eliminate it by carefully matching engine speed to wheel speed when changing gear (which i know i should alway do).

There is some rotational play at the input flange but from what i can tell no more than the diffs they replaced (which didnt have this problem).

Where should i be looking to identify the source of this or is it likely the sum of several tollerances?

Cheers for the help. Starting to feel a bit defeated by the list of things i need to sort at the moment!

Also the backlash could be worn centre diff shims,
engage the difflock & go for a drive on a gravel road and compare backlash 'clunk' with when the CDL is disengaged