diff noise??

bones · Post by **bones** » Tue May 18, 2010 9:20 am

Hi all. Ive had a lsd diff put in the rover sd1 axle, the diff went from 8 plates to 16, but when driving it the noise from the axle sounds like a loud ticking as if something is turning and hitting something, but when floored it goes away.is it suppose to be like that??? It drives me nuts when driving around town at 30 and 40mph.All advice welcome. Maybe i should just floor it all the time

rich

kiwicar · Post by **kiwicar** » Tue May 18, 2010 11:01 am

If you want to use a straight salsbury type diff you will have to live with it, they are pretty noisey (the ticking is the plates slipping and re gripping as you corner) there have been various "design modifications" like the use of an oil pump to put preload onto the plates when you start to get wheel spin (jeeps use them) but then you end up with initial wheel spin. Your alternative is to use another type of diff, Quaif, viscous, pawl ail locker all have advantages and dissadvantages.. .
Best regards
Mike

topcatcustom · Post by **topcatcustom** » Tue May 18, 2010 11:59 am

If its when driving in a straight line though the plates shouldn't be moving at different speeds- might be worth jacking the rear end up and turning the wheels by hand with you underneath to try and locate it exactly.

bones · Post by **bones** » Wed May 19, 2010 9:09 am

it ticks when going in a straight line but goings when i accelerate, and it doesnt like going around corners anymore, you can hear the wheel skid as i go round them. there is no give with the extra plates. I will check it out as i cant afford to do the axle again.

rich

topcatcustom · Post by **topcatcustom** » Wed May 19, 2010 9:21 am

It is an LSD Rich... Pull it out and have a good look on the bench if you get time.

bones · Post by **bones** » Wed May 19, 2010 9:53 am

Hi TC ,yes it is a LSD multi-plate diff. i think i better make time to check it, will take the plate of the back and turn the wheels to see whats happening in there. I take it the plates are the noise makers. first time with LSD so not sure how it works.

rich

kiwicar · Post by **kiwicar** » Wed May 19, 2010 11:10 am

Hi Rich,
many years ago a mate had one in the front of a Mini, it had on carpets, no sound deadening and a 1430 motor on straight cut box and straight cut drop gears, a large bore exhaust and a single straight through box. On a straight stretch of relativly smooth duel carrigway on a light throttle the diff could be heard over all the racket that lot created and sounded like a cross between a steel rule rattled on a table and someone hitting a bag of bolts with a hammer, go round a corner and apart from the initial "resistance" to doing anything but go straight on it made a noise like bolts in a food processor. Put full power through it by dumping the clutch at 6.5k revs and it was as quiet as a mouse as doing that locked it solid. They really do make a disturbing noise if you aren't used to them and the more plates you put in to transmit more power with out spinning a wheel the worse it is.
Best regards
Mike

bones · Post by **bones** » Wed May 19, 2010 11:21 am

Hi Mike, that description is spot on to how mine sounds, asoon as i floor it the sound goes ,ease back on throttle and the sound is back. Maybe i should get some ear plugs

rich

topcatcustom · Post by **topcatcustom** » Wed May 19, 2010 11:30 am

So it must be down to the plates rattling on the splines? That would explain why they stop making noise when you floor it and they are pushing against 1 edge only.

kiwicar · Post by **kiwicar** » Wed May 19, 2010 12:47 pm

Hi Tom,
the plates are held by preload springs so they are always slightly loading the clutch plates to the sides of the diff, they always offer resistance, on light throttle teven on a reasonably straight road they are continually sticking and slipping, loading and unloading the sun and planet gears in the diff and the crown wheel and pinion aswell, net result plates, and all the gears in the diff are continually generating noise. Hit the throttle and a set of pawles acting on the plates/diff force the clutch plates even harder together so the diff can't slip locking the sun and planet gears and at the same time unloading them and the load on the crown wheel now is pretty well constant hence all the noise goes. . . "it's a feature sir!"
As I said earlier the noise is a result of how they work, there are other designs that get around it, notably the ones in jeeps, by doing away with the preload on the plates, so making it an open diff, and then using an oil pump in the diff to load the plates as one wheel starts to spin.
Best regards
Mike

kiwicar · Post by **kiwicar** » Wed May 19, 2010 12:48 pm

Hi Rich
ear plugs work a bit, thick carpet in the back helps, sound deadening material over the diff casing, sing loudly. . .
Mike

bones · Post by **bones** » Fri May 21, 2010 9:05 am

I will sing real loud as the back seats will be coming out on race day. Might just get a 500 watt stereo fitted and play my ZZ top or rob zombie cd,s that will cover it up

rich

bones · Post by **bones** » Mon Aug 16, 2010 2:31 pm

well the axle is a pain in the arse. after changing the c,w,p again as pinion was damaged. Took out for a teset and the same noises can be heard when turning, a clinking of metal and axle moves towards the rear of arch. Could the sway bars have metal bushes instead of the polysport ones its got fitted. Any ideas on the noises needed.

rich could the lsd have to many plates in it, or could pre-load be wrong. How does the pre-load work ??, as there is no give when going round bends, on a right hander the offside tyre bonces abit.

rich

bones · Post by **bones** » Mon Aug 23, 2010 2:54 pm

well ive found the problem with the axle, one side of the diff all the lsd plates and case part had twisted and jammed solid,

rich

mgbv8 · Post by **mgbv8** » Mon Aug 23, 2010 6:20 pm

Is that a warrenty job Bones??