Diff Change?

[Shaun B]

I have two MK5's minibuses, one is fitted with the 4.11 diff and the other is fitted with the 4.56 diff

The one with the (desired) 4.11 diff cruises very nicely at 70mph and is nice and quiet, with low revs.

The one with the 4.56 diff screams at 60mph and sounds like it's doing 130mph!

Is it a simple case of just locating a 4.11 diff and swapping them over? are there any marking one the exterior of the diff to tell me it's a 4.11, i can't make any of the stamped details out on the exterior of the diff.

has anyone done this?

Shaun

[mickdee]

If you are unsure what to do:-

GIVE ME THE 4.11

Seriously tho Shaun,there will be many members on here who have done this,i am sure a reply will come shortly.

Do you have a rev counter in the bus with the 4.11 ? If so,what revs is she doing at 70 MPH ?

[Luke]

there should be a tab on the diff over one of the retaining bolts but the only way to be 100% sure is count the turns or count the teeth

and it will swap like for like with a 4.56

[Shaun B]

Luke,

The numbers on the tag are quite corroded and difficult, but not impossible to read.

It would help if I knew what I was looking for on the tag!! Is there a code number for the diferrent diff ratios or will it be the actual diff ratio stamped on it?

Mickdee,

Niether vehcile has the luxury of a rev counter, but the 4.11 vehcile cruises at 70mph with a guestimate of about 3k rev's The one with the 4.56 struggles to reach 70mph!!!

Shaun

[MinorMatt]

The ratio itself will be stamped on to the plate. If you are at the scrappy, jack up one side, get underneath and turn the wheel. If its a 4.11, 2 revolutions should equate to 1 revolution of the propshaft, if it a 4.56 it will be 2.25 revolutions to one propshaft revolution (I think)

[Timbo]

Don't forget to change the speedo drive gear in the gearbox so that the speedo reads correctly.

[mickdee]

Mickdee,

Niether vehcile has the luxury of a rev counter, but the 4.11 vehcile cruises at 70mph with a guestimate of about 3k rev's The one with the 4.56 struggles to reach 70mph!!!

Shaun

OK mate cheers.

[mickdee]

OOPS double post.

[Shaun B]

I had a look at a transit in my local scrappy, and could not make out the markings on the tag to see whta diff it was.

I turned the rear wheel and got 2.25 turns of the wheel to 1 full turn of the prop, so this is not a 4.11 diff??

Was there a particular model that had the 4.11 diff fitted?

Shaun

[Luke]

I turned the rear wheel and got 2.25 turns of the wheel to 1 full turn of the prop, so this is not a 4.11 diff??

as its turning 1 wheel its doubled so 2.25 will be 4.5 as theres no exact 4.5 chances are it'll be 4.56

[Shaun B]

Luke,

using this "Wheel Turning" method obviously isn't an exact science, but for it to be a 4.11 the rear wheel would have to turn 2.05 turns rather than 2.25?

I might double check those turns! it's a very small margin for error in a muddy, wet, cold scrapyard!!

How many teeth should a 4.11 diff have?

Shaun