Transfer case, Auto or diff(s) - massive backlash

**Toppa** · 23rd January 2013, 07:25 PM

Disco 2 TD5 Auto with 275,00kms

If possible I would like to know how to test which component is the source of my backlash before I go spending thousands on what i think it might be.

The backlash i get when coasting to a stop from say 60 kms/h almost feels like i get hit by a car from behind. Just before i brake to a halt, it clunks from 3rd to 2nd, then moments later from 2nd to 1st. Also similar to dropping the clutch in a manual. Nasty.

I have just put a Tom Woods DC shaft in the front which helped smooth things out a little and got rid of my vibrations (centre bearing was shot and i'd already rebuilt it once before so it was an upgrade I was already planing)

Rear tailshaft Rotoflex and uni look good

My initial thoughts were the Auto - ive seen a fair increase in fuel consumption - but ive added plenty of wind resistant accessories - still i dont think it accounts for all of the increase. I performed the stall test and it fell within acceptable rev range.

However, when changing the T/case oil last service, there was evidence of water. Could this have degraded bearings or gears in a way to exacerbate backlash?

Diffs are also a chance I suppose?

Its never been driven particularly hard apart from my last trip to the high country where the auto overheated - 150 deg C on my madman and dash light on. id stop and let the auto cool down as soon as this happened. I put this down to mud in the auto trns cooler and low oil volume in the auto due to a slow leak, but not 100% sure of the oil level theory. I serviced the auto (filter gasket and oil) on my return. Oil was brown when dropped.

The auto changes pretty well on the upshift, but there is a noticeable delay and clunk when putting the disco in reverse

SO, can i remove shafts and wobble / rotate etc where excessive play will tell me this is a problem. What other tests should I try? I just want to formulate a plan of attack - ie purchase a recently reco'd t/case or auto and have a specialist remove old and install new.
Its my daily driver so as much as im pretty mechanically minded, the T/case or auto are not going to be changed in my driveway like i'd normally do.

OR am i better to take it to a driveline specialist and get them to diagnose it - like A+B in Dandenong.

Money is tight hence why looking at good s/hand rather that reco'd - false economy probably?

**northiam** · 23rd January 2013, 07:46 PM

When I replaced just the rear tyres on my D2 td5 auto driveline backlash was huge! Few weeks later replaced the front tyres backlash gone. Was different diameter (worn) tyres causing axles running at different speeds I put in down to.
I feel the backlash coming out of a roundabout still.
Regards

**Toppa** · 23rd January 2013, 07:53 PM

Thanks Northiam, how i wish it were that easy. I just swapped back to my road tyres from my Mud set. Massive drop in vibration, but unfortunately nill effect on backlash

**Dougal** · 23rd January 2013, 07:58 PM

Chock the wheels, unlock the centre diff, TC in neutral and handbrake off.

Get underneath and twist the prop-shafts by hand. This will expose backlash in the diffs front and back.
To expose backlash in the centre diff you need to park it in gear (or park if auto) with the handbrake off, wheels chocked and jacked off the ground at one end. Turn the prop shaft of the end off the ground and see how much backlash exists before the other shaft out of the TC moves.

The ultimate solution is Ashcrofts ATB diffs. They do them for front/back and soon for the TC too. Torsen type limited slip which are much stronger and should have much less backlash.

**loanrangie** · 23rd January 2013, 08:14 PM

Originally Posted by northiam

When I replaced just the rear tyres on my D2 td5 auto driveline backlash was huge! Few weeks later replaced the front tyres backlash gone. Was different diameter (worn) tyres causing axles running at different speeds I put in down to.
I feel the backlash coming out of a roundabout still.
Regards

Sorry but unless your tyres were inches apart in diameter there is no way the small difference between new and worn tyres would affect the backlash, the centre diff will cope with much larger offsetts than that.
Even different sizes front to rear will have no affect unless you had the TC locked.

**Slunnie** · 23rd January 2013, 08:21 PM

My auto would clunk around pretty badly when shifting down to 2nd and 1st when there were some faults logged in the auto computer. Much much harsher than diff, transfer case or propshaft lash.

**northiam** · 23rd January 2013, 08:46 PM

Apply handbrake rock the car back and forth note travel.
Release handbrake auto in Park repeat. Will eliminate transmission at least.

**Toppa** · 23rd January 2013, 09:17 PM

Cheers - ill definitely try the Dougal and Northiam methods over the weekend.

Oh and the ATB's are the top of my mods wish list, which unfortunately takes a big back seat to the 'needs' list - but nevertheless they are on there!

Sent from my GT-I9100T using Tapatalk 2

**emanwa** · 5th August 2013, 10:08 AM

Just curious but did you ever get to the bottom of this issue or not.

**Toppa** · 5th August 2013, 10:40 AM

Nope, just living with it for now. I did purchase an ATB but yet to fit it.

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