Thread: driveline backlash

Sounds good to me.

Could well be the diffs

Have you checked the axles and drive flanges. These are normally the first to wear - normally good for 100,000kms unless using the wider maxi flanges. Easy to check - just jack up 1 wheel, remove the center cap (rubber/plastic/,,,) and rotate the wheel. Any movement between the axle and drive flange will be amplified 4 times as all wheels usually wear at a similar rate.

Erich

prop shaft movement will only ever be as much as the side with the least amount of lash

on the diff side that will be flange to pinion lash + CWP lash + Spider lash +spider to shaft lash + shaft to flange lash. Dont forget that both sides of the spider gears and both alxes have to take up and then due to the arrangement of the spider gears in the diff you get a mulitplier for the lot before the CWP take up.

on the tcase side you have flange to shaft lash + Center diff lash (which includes the spiders and the movement all the way down to the wheels on the front if your checking the rear or into the handbrake/rear wheels if your chechking the front shaft) + the gear train lash to the input gear + input gear to gearbox output shaft lash +internal gearbox gear lash + input shaft to clutch lash...

so yeah compared to some vehicles that dont have all that the shaft movement will seem to be a bit.


out of curiosity how are you doing your checks?

Originally Posted by Blknight.aus

prop shaft movement will only ever be as much as the side with the least amount of lash

on the diff side that will be flange to pinion lash + CWP lash + Spider lash +spider to shaft lash + shaft to flange lash. Dont forget that both sides of the spider gears and both alxes have to take up and then due to the arrangement of the spider gears in the diff you get a mulitplier for the lot before the CWP take up.

on the tcase side you have flange to shaft lash + Center diff lash (which includes the spiders and the movement all the way down to the wheels on the front if your checking the rear or into the handbrake/rear wheels if your chechking the front shaft) + the gear train lash to the input gear + input gear to gearbox output shaft lash +internal gearbox gear lash + input shaft to clutch lash...

so yeah compared to some vehicles that dont have all that the shaft movement will seem to be a bit.


out of curiosity how are you doing your checks?

Dave, if you were to jack up the rear on one side mark the tyre at the bottom and continue that line onto the ground, how far do you think the tyre mark should go past the ground mark when rocking the wheel backward and forward, on a deefer that is


Cheers Sumo.

Originally Posted by lambrover

actualy checking diff backlash,...... I think rovers suffer from excesive backlash problems ....... when I checked my new project car a v8 county ....... both diffs feel as they have more than standard backlash, ....... this can only be corrected by re-doing/ setting the backlash. Dose this make sence.

Backlash

This is my understanding of diffs (at the risk of being flamed via others .. So correct me if I am wrong)
Based on a "open center" type only (RRC)

Your diff could be perfectly fine ...... Just old with too many k's on it
The face of the teeth of the Crown & pinion have just worn down = play
The face of the teeth of the Spider gears have just worn down = play

This puts more space between the edges of the corresponding teeth where they join (Crown tooth to pinion tooth)

Also the center Hemisphere could have some wear in it's pin joint

To adjust the lash is not (most probably) the answer, as you set the crown "Center to pinion" ..... If the diff "whines" ... Then it needs to be checked and have the crown & pinion re-adjusted ... As it needs to run face to face (of teeth) "centered" .... The amount of backlash is governed by this visual setting

So in short /// If the diff doesn't whine (no gear noise) ... answer is NO .. Backlash setting is fine

If you wish to remove more backlash ... then the answer may lay in the purchase of "All new gears" for the diff = $$$$

Hope it make sense


Mike

brand new, with a rear wheel raised with the wheels chocked and the handbrake off with the thing in first gear 4-6 inches but thats the worst case for a backlash check as you have take every little bit of lash out of every part of the driveline before it will stop.

again with the handbrake on hard and the same rear wheel up maybe 2-3 inches new.

Id generally agree with what mike 90 had to say but the lash can be taken out of a worn diff if its only the CWP thats sloppy generally tho I wouldnt bother with it unless it was excessive and I had to pull the diff. If I was pulling the diff just for lash reasons Id be checking the flanges and the axles for damage before looking at the diff partly because they have to come out first anyway and partly because they are generally the bits the wear most anyway. The condition of the axles and the oil will also (in part) giveaway the condition of the spiders. look and sometimes you can get a ready to go diff in a carrier for less than the price of a CWP, spiders bearings and the shims youd need to setup the diff from new. If youve never setup a diff before ID reccomend that even if it cost more than the parts so long as it had 12months warrenty with a fair use coverage I'd still reccomend getting the replacement.



Dont get cross axled over the its a deefer/its a disco/its a rangie when it comes to lash, the tech in the driveline is identical with the exception that the deefers all have Uj;s in the prop shafts and some discos have donuts. Neither of those items should contribute anything to your lash and if they do then you should be replacing them immediately.

Even the new ones with their independant suspension have the same component in the same places to contribute to drive line lash. While the independants have more parts in them that can contribute to lash the extra parts that can contribute shouldnt contribute in the same way that the UJs in the propshaft shouldnt contribute to driveline lash and if they do should be replaced.

I checked mine by getting under the car with handbrake off and rocking the pinion flange, this would give the collective backlash of the final drive assemble, CWP, spiders and axle to drive flanges, to my thinking.

Simply changing to a heavier grade of oil help both my LR's a great deal.If you really want to tighten it up re-shim your center diff so that it has no more than 7thou endfloat and run ATF for 3 months before changing back to oil and there will be no ''slop'' in your gearbox-transfer.That was what a local LR mechanic used to do and it worked a treat.His reason was that 12thou was standard and by the time everything beded in it was well over 20 so setting it tight and using ATF it was at spec after settling in. Pat