DIFF CLUNK - Combined Approach

[jetute]

After some thought I decided to do alittle research into the topic of driveline shunt. After abit of a search on the web I found "shock horror" that it is very common amongst even some of the prestige brands. Here are some links to articles with a brief summary from each one if the articles are too long to read.

Audi RS4: Along what way, you'll encounter a relatively heavy clutch and some driveline shunt from their six-speed manual gearbox - an annoying trait shared with most other Audis. But if you were expecting a wild ride to accompany that flipping performance, you'd be in for a surprise. The RS4 is hushed and refined, and at low speeds is compliant and comfortable rather than sharp and edgy.

Link to rest of article: http://www.google.com.au/search?q=cache:Sd...ine+shunt&hl=en

BMW Z4: As usual, the six is a model of refinement and smoothness and BMW have indulged themselves and even allowed it a deep burble to the exhaust note at lower crank speeds, and some crackle on the over-run. It's another great application of the six, although the 5-speed 'box isn't as slick as some we've experienced lately, though it does retain a wonderful mechanical feel. There was the slightest driveline shunt at lower speeds, although this wouldn't be so evident if the driving position weren't set so far back in the chassis.

http://www.carenthusiast.com/roadtests.html?article=298

Mazda RX-8: Unlike previous rotary engines, there is far less driveline shunt, although edging along at very low speeds can be jerky if you're not delicate with clutch and throttle.

http://www.tiscali.co.uk/motoring/roadtest...ction5/892.html

2002 Mustang GT: The manual gearbox has a notchy, agricultural feel. Driveline “shunt” – the judder and thunk that arises when slack in the drivetrain is taken up under acceleration, or released during deceleration – is pronounced, and the pedals occupy the same basic area but operate on three different planes.

http://www.autofieldguide.com/driven/0702dri04.html

Maserati Coupe: It is almost like an auto in its behaviour and creamy smooth to boot.  Some driveline shunt however, can upset serene progress.  The engine note in town driving is muted, never intrusive, but musical.

http://www.pistonheads.com/doc.asp?c=47&I=8717

The point of this post is that it is not just manual Falcons that have shunt. Fact is it happens and unless there is more dampening within the driveline it will coninue to be there. So all this talk of blockading dealerships seams all the more absurd.

no1 is saying there are no other cars out there have driveline shunt...... I personally am not happy with my shunt as it worsening on a daily basis and also because I know there are other manual owners out there that dont have it.... why should I have to put up with it when the next bloke doesnt??? I guess if they were consistent with producing nothing but clunkers a lot of people would not be complaining. We all pay the same money, and we all deserve the same product

[RATT]

jetute, I am in no way endorsing the issue. I am merely stating that it is commonplace and to be quite honest not many, if any people have mentioned that driveline shunt is prevelant in other manual trans. vehicles.

Working where I do I have had the opportunity to drive many manual trans. BA's and the odd VX-VY Late model camira and the same issue arises in all cases, it's that it varies but they all had a degree of shunt. Some felt tighter and others no so tight. Being too tight is probably not a good thing but I guess it's the tolerences that are the issue here not the shunt itself.

Edited 21/11/04 10:33 PM by RATT

[jetute]

I think you just hit the nail on the head

[xr6 typhoon]

to everyone following this thread just thought I'd let you all know that on my work travels I pass the Dana site on Fairfield Rd Yenora nealry everyday and everyday without fail there are several BA's in the carpark near the inspection bay or on the hoists in the inspection bay at the front of the building all of which you can see from Fairfield Rd. My theory is Dana are trying to find a fix to the problem. Is there someone out there who can enlighten us?

[Guest mrtg]

I dont think that this problem will go away ALL Au manual's with irs seemed to suffer this problem,it drives you mad that's why I now drive a Territory.

[ZAP]

Well I had my mechanic follow Mal Wood's (Ben) instructions on how to measure the backlash. They said that there is only a little bit of backlash in the gearbox/diff, but they think it is the rear subframe and suggest I get the car on a 4 wheel alignment machine to see if the rear geometry is right. They think it is causing the clunking.

I guess I will try that and see if it is the cause.

Part 6 of trying to fix this problem...........

[JB]

Well, diff no 4 is in I thought I would keep you all in the loop.

The car was in for 2 days and had the following done:

New Diff

New Gearbox (Transmax Z oil to be put in)

New clutch -Supplied by JB

Machine the flywheel

Machine the discs

Fit new pads - Supplied by JB

New Tint on rear left hand door

Reflash Pcm

Replace Gear knob

Replace Leather Gear boot

The car has been interesting since I got it back, the gearbox is great (*touches wood*) and they happily put in transmax Z oil for me. In relation to the clutch, it is a pig at the moment. I put in a heavy duty one which needs 1000 k's of bedding in. At the moment it is either on or off, and if you do not get it right it shudders like a pig, but I am hoping long term will be great.

The Diff is alot better the car feels very tight in the driveline, the whine is not apparent, there is the odd clunk, and still that looseness feeling in the drivline when power is not being applied, but I think I am resigned to the fact that it will never be any different. It has had most of the driveline replaced and is still there so the only other thing I can think of is Zap's suggestion of Rear end geometry, but I am in the mind set now of just wanting enjoy the car.

Time will tell again, I am very confident in the box, but like my last diff, we will see if this one deteriorates over time.