Backlash issue - Sals diff

[phibbzy]

Hi all,

I've been tracking down a backlash issue for quite a while now...

Upon taking off from a standstill there is a take up and an aggressive "clunk" from the under carriage. When on power there is no issue but when moving along and removing power quickly there is another take up and then a clunk.

When lifting one wheel of the vehicle with a jack & idling in 1st high, upon applying slight power and then releasing it the take up is enough to move the vehicle.

There is about 1/8 turn of slack in the prop shaft between either wheel (of the ground ) moving.

I have ruled out either by testing or replacing:


Front & rear flanges
Front and rear half shafts look fine removed - no sheering of the teeth
UJ's in both prop shafts
Gearbox mounts & engine mounts
transfer case rear & front flange play LOOKS within spec. There does not appear to be any play between the engine (flywheel locked) and the hand break thus not an issue with the output pinion sheering
there is only a fraction of the slack in the front diff (around 1/32 of a turn?)

It's starting to look like the rear sals diff has an excessive amount of play in it. Can someone confirm how much play there should be? The diff gets rather warm on 50km trips - not impossible to put my hand on but rather uncomfortable! Around the same as the gearbox/transfer.



Is it possible to reset the backlash of it, or am I to look for a new diff center? Any further tests I can try on other equipment?

[clive22]

Hi

Check you're ball joint on the A frame the symptoms sounds characteristic of this being worn.

Worn ball joint allows diff assembly to rotate a small amount then clunks when runs out of play.

Temp/Heat in Sals sounds about right uncomfortable to touch or somewhere about 60 degrees.

Clive

[steveG]

What play do you see when you put the handbrake on, jack up one wheel and try to rotate it?
Any backlash has to be from handbrake drum rearwards.

With the vehicle in gear (engine not running) and handbrake on, jack up one front wheel and see how much it rotates. Any backlash is between clutch and front wheels
Repeat with the center diff locked. Any play is between front output flange and front wheels.

That should give you a pretty good idea of where to concentrate your efforts on.

I doubt that the backlash is in the Sals, but its possible.

Steve

[rick130]

You'll burn skin on a Sals after a good highway run of a couple of hours, hypoid dffs generate a bucket load of heat.

[Bearman]

Another thing to look at if you narrow it down to the rear is slop in the diff centre. It is unlikely it is backlash between pinion/crownwheel but more likely slop in the side gears/pinions. They do have replaceable thrust washers under them and is not a big job to replace them. Check the gears and crossshaft for wear while you are at it - it all contributes to slop at the wheel.

[harro]

Sounds like you have checked all the usual suspects.
It looks like centre out and backlash reset as you have said.
Shims for the sals.
Have a look at this;
Land Rover Addict Forums (http://landroveraddict.com/forums/thread.cfm'threadID=15206)

Cheers,
Paul.

[phibbzy]

Hi

Check you're ball joint on the A frame the symptoms sounds characteristic of this being worn.

Worn ball joint allows diff assembly to rotate a small amount then clunks when runs out of play.

Temp/Heat in Sals sounds about right uncomfortable to touch or somewhere about 60 degrees.

Clive

I've had a bar on the A-Frame joint and there is no play, so I have ruled that one out.

[phibbzy]

What play do you see when you put the handbrake on, jack up one wheel and try to rotate it?
Any backlash has to be from handbrake drum rearwards.

With the vehicle in gear (engine not running) and handbrake on, jack up one front wheel and see how much it rotates. Any backlash is between clutch and front wheels
Repeat with the center diff locked. Any play is between front output flange and front wheels.

That should give you a pretty good idea of where to concentrate your efforts on.

I doubt that the backlash is in the Sals, but its possible.

Steve

Rear driver wheel jacked up, hand brake on, rear pass wheel on the ground - wheel rotates AROUND 30 degrees (memory serving me here, will confirm tonight). With both wheels on the ground, hand break off (and indeed without the prop shaft on the vehicle at all) the rotation on the input pinion on the sals is about 1/8th of a turn before any take up.

Front in the same circumstances seemed good - pinion was only moving a FRACTION.

I'll look into these shims in the sals. Guess its time to get a manual from somewhere and finally invest in that DTI gauge?

[2stroke]

Have you checked the drive flanges? The most common source of backlash, even lack of drive in extreme cases.

[85 county]

Rear driver wheel jacked up, hand brake on, rear pass wheel on the ground - wheel rotates AROUND 30 degrees (memory serving me here, will confirm tonight). With both wheels on the ground, hand break off (and indeed without the prop shaft on the vehicle at all) the rotation on the input pinion on the sals is about 1/8th of a turn before any take up.

Front in the same circumstances seemed good - pinion was only moving a FRACTION.

I'll look into these shims in the sals. Guess its time to get a manual from somewhere and finally invest in that DTI gauge?

Na forget that, just get a locker

[wrinklearthur]

Na forget that, just get a locker

Re our phone call, I will be hanging onto that locker I have. I was then thinking that it isn't long now until Agfest, so if I was you, I'd hang on till then and after getting your best pair of thumbs screws out, go and pay the ARB guys a visit at their tent.

That A frame top ball joint can also be brought as a heavy duty / greasable unit and that's the way to go for the long haul IMHO.
.

[phibbzy]

Re our phone call, I will be hanging onto that locker I have. I was then thinking that it isn't long now until Agfest, so if I was you, I'd hang on till then and after getting your best pair of thumbs screws out, go and pay the ARB guys a visit at their tent.

That A frame top ball joint can also be brought as a heavy duty / greasable unit and that's the way to go for the long haul IMHO.
.

Lol.

Hedging my bets! A nasty clunk is a good excuse to get a locker past the new however...

[2stroke]

Have you checked the drive flanges? The most common source of backlash, even lack of drive in extreme cases.
I'm talking about the axle drive flanges, they always run dry and wear out. If you prise off the rubber end caps and rock the wheel back and forth with the handbrake on you'll see any problem there.

[phibbzy]

I'm talking about the axle drive flanges, they always run dry and wear out. If you prise off the rubber end caps and rock the wheel back and forth with the handbrake on you'll see any problem there.

Yeh mate, was top of the list in OP. Both ends have been upgraded to terrafirma HD flanges. They're tighter than a gnats chuff and not the source. I've had the half shafts out and the teeth are fine - no wear... The rear are HD axles as well.

[dero]

Have you solved your problem ? I have been putting up with similar symptoms for quite a while .
My A frame ball joint looked ok , but after replacing it and the bushes this morning , all is well . I have been putting the job off , but after much grunting , skinned knuckles and a can of freeze & release [wonderful stuff ] it's done . Much nicer now . Now for a well earned rum .

[85 county]

Re our phone call, I will be hanging onto that locker I have. I was then thinking that it isn't long now until Agfest, so if I was you, I'd hang on till then and after getting your best pair of thumbs screws out, go and pay the ARB guys a visit at their tent.

That A frame top ball joint can also be brought as a heavy duty / greasable unit and that's the way to go for the long haul IMHO.
.

what phone call???

[wrinklearthur]

what phone call???

The one I made, don't you know? :p
.

[phibbzy]

The one I made, don't you know? :p
.

When a locker was on the list I called the bloke in the know :D:D

A Frame LOOKS fine... I COULD change it to a grease unit & I probably will soon however judging by the looseness in the rear diff and info provided I'm looking there. Had a mate look under there whilst I moved about in first and there is no movement in that area though.

When CDL is locked in low there is NO backlash... not sure about high - was on the tail end of a days work and didn't feel like diagnostics :angel:

Good excuse to get a locker passed the mrs!! :twisted::twisted:

[phibbzy]

Hi guys,

Bumping this post as I have organised a rear locker to go in. They had them for $1000 + $600 install at agfest which was a great price :D

Problem is the boffins at ARB in town reckon this will not fix the issue with the backlash :(

Heres me thinking they would set the CW+P up if that was the issue but they dont change anything. It's kind of gone over my head as to why they dont do that and why a new center wouldn't fix the issue but time will tell...

Do they even make crown wheels and pinions for these diffs any more or will I be looking at a 2nd hand part if its at fault??

[Samblers]

Is it a stupid suggestion to take it to LR and get them to at least diagnose? They must have run this procedure countless times - the Perth local dealer has anyway.

They fixed my backlash

[chopper]

Hi guys,

Bumping this post as I have organised a rear locker to go in. They had them for $1000 + $600 install at agfest which was a great price :D

Problem is the boffins at ARB in town reckon this will not fix the issue with the backlash :(

Heres me thinking they would set the CW+P up if that was the issue but they dont change anything. It's kind of gone over my head as to why they dont do that and why a new center wouldn't fix the issue but time will tell...

Do they even make crown wheels and pinions for these diffs any more or will I be looking at a 2nd hand part if its at fault??


$600 ! , is that to fit a Detroit type guts in your hemisphere or to fit an air locker ?

[phibbzy]

Is it a stupid suggestion to take it to LR and get them to at least diagnose? They must have run this procedure countless times - the Perth local dealer has anyway.

They fixed my backlash

I guess... The LR guys up here probably wouldn't even know what a salisbury is though so it would be a trip to hobart and a date with JC :P


$600 ! , is that to fit a Detroit type guts in your hemisphere or to fit an air locker ?

Its an Air locker with compressor install etc... $600 is steep but I want it done right.



I'd look at investigating it myself or even fixing the backlash but diffs are an unknown for me, haven't had much chance to figure them out and salisbury being a different design I'm put off. Also the advice ARB gave was that fixing the backlash on the diff might well cause it to fail as its running on different faces of the CW+P?

[85 county]

I guess... The LR guys up here probably wouldn't even know what a salisbury is though so it would be a trip to hobart and a date with JC :P



Its an Air locker with compressor install etc... $600 is steep but I want it done right.



I'd look at investigating it myself or even fixing the backlash but diffs are an unknown for me, haven't had much chance to figure them out and salisbury being a different design I'm put off. Also the advice ARB gave was that fixing the backlash on the diff might well cause it to fail as its running on different faces of the CW+P?

Mate a salisbury is just a diff. just that you set them up on your back not your feet. and there is less boults to muck about with and less lifting

[Bushie]

I had an ARB locker installed in my salisbury around 4 years ago, pretty much totally eliminated the backlash present.


Martyn

[phibbzy]

I had an ARB locker installed in my salisbury around 4 years ago, pretty much totally eliminated the backlash present.


Martyn

This is essentially what I'm hoping will occur. I think I can feel where the pinion contacts the crown wheel when turning the flange with the rear prop off and the remaining movement is post contact to a large degree. Given the flanges, axles(these are HD units), A-frame etc are all in good order I'm just left to figure the center is the culprit.

I'll let ARB work their magic and go from there. If it needs further work then so be it, as long as the outcome is a good strong diff.

[KeithMac]

Is it a stupid suggestion to take it to LR and get them to at least diagnose? They must have run this procedure countless times - the Perth local dealer has anyway.

They fixed my backlash

Samblers, which Perth dealer did you use, and how much did it cost?

[2stroke]

One option is to take off the inspection cover and take a look. You'll soon see if there's a crownwheel backlash problem, and if it's just in the differential, you'll know the locker will fix it.

[wrinklearthur]

One option is to take off the inspection cover and take a look. You'll soon see if there's a crownwheel backlash problem, and if it's just in the differential, you'll know the locker will fix it.

X2.

That would be my approach also, James.

If the crownwheel and pinion has been running for a considerable time with excessive backlash, the only way then to set it up is to 'blue' the teeth and get the best match with the contact marks.
.

[phibbzy]

Righto, lets see what I find...

[Samblers]

Samblers, which Perth dealer did you use, and how much did it cost?

Choice is Barbagellos or Barbagellos. Cost me nothing (warranty)

[Jode]

Do they even make crown wheels and pinions for these diffs any more or will I be looking at a 2nd hand part if its at fault??
I KNOW that Ashcroft sell CW&P for the Rover diff, and THINK they also sell new for the Sals.

[2stroke]

Because crownwheel backlash, as well as bearing preload in a sals is set by shims at assembly, the only way to develop excessive backlash (assuming proper setup to begin with) is excessive wear. Or perhaps the pinion crush tube has crushed? Surely by then it'd have to howl like a banshee. Interested to know what's going on inside there.

[phibbzy]

Righto, finally had a Saturday free with fair enough weather to bear laying on the concrete for a few hours.

Removed the plate and had a look.

At this point any particular tests that would yield information would be helpful :)

I couldn't figure a way to lock the pinion up 100% but the crown wheel, dial gauge horizontal at the exterior of the wheel had .48mm of backlash.

placing the dial gauge on the horizontal plane against the crown wheel and using a pry bar to move the diff itself yielded .22mm of play - however i'm not sure I did this test correctly.

There is some minor putting and rust on a couple of the outer edges of the coast side of the pinion.

I have put the ARB install off for the moment. Might be looking at a new whole axle yet!

There is water in the oil - however the recent trip saw the vehicle sitting in water for 5 minutes or so that was over the bonnet :eek: so that could attribute to it - obviously the breather is something I need to look into soon but the diff comes first.

[steveG]

Lock the crownwheel from rotating by using a small wedge of wood etc to jam it against the case. With the handbrake off, check how much rotation you get on the input flange, and compare to when the crownwheel is free to rotate. Since you have already checked drive splines etc prevoiusly and not found any play this will give you an idea of how much if your play is in the spider gears and how much in the crownwheel/pinion backlash.
There shouldn't be any lateral play in the crownwheel - there should be some preload in the bearings. From memory the manual says to set it up initially with clearance, measure how much and then add a specified amount to get preload. The total is total thickness of shims to add.

Steve

[phibbzy]

Updating and bumping this thread with what I hope is a resolution to the major backlash problems I've had...

The diff in the end proved to be somewhat worn but okay. I ordered a mechanical locker which arrived broken in the post so gave up and went all in for an E-locker :angel:

I decided to replace the A frame ball joint, just in case.

5 hours of trying to remove rusted castle nuts, corrosion bonded ball joints and cleaning crud from my eye every 15 minutes I had the fulcrum in one hand and the passenger side top link in my face.

Yep, the bush on the passenger top link had eaten through the bolt on either side, allowing a LOT of movement... however it did not allow any forward, back, up or down movement making it near impossible to detect with a pry bar.

http://youtu.be/UnGv8BwtRy0

Here's a video of it on the table...

Going to sand blast and paint the arms and mounts with new bushes, bolts, nuts and see how it goes...