Checking DMF play with the gearbox in place

Mike Noc · 14th August 2013, 10:55

When trying to sort my drive clunk yesterday with the car jacked up and in gear I'm sure I could hear the DMF springs taking up the play when rocking the wheels.

Thinking about it this could be a good way to check the play in the DMF. With the car in 5th gear and just the passenger front wheel off the ground the play when rocking the wheel will be in direct relation to the amount of play in the DMF.

The gearing is a factor of course, and the differential will be operating.

So if anyone is changing their clutch can I ask a favour - do the above check before you start work and measure the amount of movement on the outside of the tyre. Then measure the play in the DMF once the box is off and we can compare the two figures.

With a few readings we should be able to come up with an acceptable limit of wheel play before the DMF is suspect.

Bolin · 14th August 2013, 11:24

Wouldn't there be a bit of play from the CV joints too, even when they are not 'worn out'?

Mike Noc · 14th August 2013, 11:31

Yes there could be a bit of play here and there but it should give a reasonable ball park figure to show if the DMF is nearing its wear limit..

FrenchMike · 14th August 2013, 11:49

Good idea Mike ,

Worth having a try

Knowing the behaviour of the DMF play is springy opposite to others

How much do you get on yours ?

Mike

T-Cut · 14th August 2013, 12:01

It's an interesting idea, but I wonder if the road wheel play would be consistant enough to enable a general 'DMF Rule' to be formulated. There is a variable backlash in every joint and gear in the drive train between the wheel and the crankshaft/DMF. I suspect - but it obviously needs investigation - that the permitted slop at the wheel will be too great to enable a reliable correlation to the DMF slop. Another factor is the sensitivity of the test. Will the wheel give a good feel of when the DMF springs are just at the contact point? It needs testing on lots of cars to formulate a rule but is certainly worth the experiment.

TC

Mike Noc · 14th August 2013, 12:02

Quote:

Originally Posted by FrenchMike

Good idea Mike ,

Worth having a try

Knowing the behaviour of the DMF play is springy opposite to others

How much do you get on yours ?

Mike

With the box off last time around at 299k miles 2 years ago it was just under 28mm, so pretty near the limit, but I didn't replace it.

I didn't go as far as measuring the play on the outside of the tyre, but can give it a go when I get a spare moment.

The interesting thing would be to compare the two readings when taken together though.

beinet1 · 14th August 2013, 12:15

Are you able to "see" the DMF play when the starter is removed??

FrenchMike · 14th August 2013, 12:15

Quote:

Originally Posted by Mike Noc

With the box off last time around at 299k miles 2 years ago it was just under 28mm, so pretty near the limit, but I didn't replace it.

I didn't go as far as measuring the play on the outside of the tyre, but can give it a go when I get a spare moment.

The interesting thing would be to compare the two readings when taken together though.

On mine at 100.000 km (110.000km now) i have mesured ,like you
about 30 mm.

I 'll have a look soon and tell the result

Mike

FrenchMike · 14th August 2013, 12:18

Quote:

Originally Posted by beinet1

Are you able to "see" the DMF play when the starter is removed??

Good question ,i think so

johnny t · 14th August 2013, 13:17

There's always seems to be a lot of worry about the dmf, has anyone had one actually fail or is it just a expensive part that we fear.
What are the symptoms of dmf problems

14th August 2013, 10:55	#1
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,551 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Checking DMF play with the gearbox in place When trying to sort my drive clunk yesterday with the car jacked up and in gear I'm sure I could hear the DMF springs taking up the play when rocking the wheels. Thinking about it this could be a good way to check the play in the DMF. With the car in 5th gear and just the passenger front wheel off the ground the play when rocking the wheel will be in direct relation to the amount of play in the DMF. The gearing is a factor of course, and the differential will be operating. So if anyone is changing their clutch can I ask a favour - do the above check before you start work and measure the amount of movement on the outside of the tyre. Then measure the play in the DMF once the box is off and we can compare the two figures. With a few readings we should be able to come up with an acceptable limit of wheel play before the DMF is suspect.

14th August 2013, 11:24	#2
Bolin This is my second home Rover 75 2.5 V6 Connoisseur SE 4dr manual Wedgewood Blue 2 04-05/06/2001 Join Date: Nov 2006 Location: N.E. Hampshire Posts: 4,617 Thanks: 289 Thanked 308 Times in 243 Posts	Wouldn't there be a bit of play from the CV joints too, even when they are not 'worn out'? __________________ "...the new Rover 75, which is a fabulous car......I think it looks fabulous....It's like sitting in a Rolls Royce......For me, this is the star of the show.....it looks so good" - J. Clarkson, motoring journalist on the launch of the Rover 75 in 1998.

14th August 2013, 11:49	#4
FrenchMike This is my second home Rover 75 Saloon Join Date: Aug 2007 Location: Avignon Posts: 4,466 Thanks: 94 Thanked 661 Times in 554 Posts	Good idea Mike , Worth having a try Knowing the behaviour of the DMF play is springy opposite to others How much do you get on yours ? Mike Last edited by FrenchMike; 14th August 2013 at 11:53..

14th August 2013, 12:01	#5
T-Cut This is my second home Rover75 and Mreg Corsa. Join Date: Nov 2006 Location: Sumweer onat mote o'dust (Sagin) Posts: 21,753 Thanks: 341 Thanked 3,660 Times in 2,924 Posts	It's an interesting idea, but I wonder if the road wheel play would be consistant enough to enable a general 'DMF Rule' to be formulated. There is a variable backlash in every joint and gear in the drive train between the wheel and the crankshaft/DMF. I suspect - but it obviously needs investigation - that the permitted slop at the wheel will be too great to enable a reliable correlation to the DMF slop. Another factor is the sensitivity of the test. Will the wheel give a good feel of when the DMF springs are just at the contact point? It needs testing on lots of cars to formulate a rule but is certainly worth the experiment. TC Last edited by T-Cut; 14th August 2013 at 12:05..

14th August 2013, 13:17	#10
johnny t Loves to post MG ZT 135+/ MG ZT 260 Join Date: Apr 2007 Location: Chesterfield, Posts: 290 Thanks: 21 Thanked 19 Times in 14 Posts	There's always seems to be a lot of worry about the dmf, has anyone had one actually fail or is it just a expensive part that we fear. What are the symptoms of dmf problems __________________ [SIGPIC][/SIGPIC]

14th August 2013, 11:31	#3
Mike Noc This is my second home Rover 75 CDT Manual Connoisseur SE, Rover 75 CDT Automatic Connoisseur SE & a Freelander Td4. Join Date: Jul 2009 Location: Hampshire Posts: 11,551 Thanks: 3,470 Thanked 3,119 Times in 2,247 Posts	Yes there could be a bit of play here and there but it should give a reasonable ball park figure to show if the DMF is nearing its wear limit..

14th August 2013, 12:15	#7
beinet1 Posted a thing or two Rover 75 2.0 V6 Auto Join Date: May 2011 Location: Sandnes - Norway Posts: 1,560 Thanks: 64 Thanked 283 Times in 174 Posts	Are you able to "see" the DMF play when the starter is removed??