Surprising satisfying diff build

[sabbot]

It was good to finally get around to installing a new 1:3.3 crown wheel and pinion from Northern Tool and Gear in my spare diff before adding it to the +2.
It was lucky that the pinion shim on the original “3.77” pinion was the right thickness for the new pinion. Setup with 9inch/lbs of preload on the pinion, 0.007” backlash and 0.005” bearing cap spread with an acceptable mesh pattern. Knocked up a brace while the diff was on the bench.
Looking forward to installing and dropping the interstate cruising revs by ~16%.

[h20hamelan]

Nice job

Gives me confidence for my impending diff project.
I dont have an extra housing though, maybe I should source one.

Keep us posted on the gearing, as this is what I have for my S4. I am guessing you will like it.

[512BB]

Yes, well done and look forward to your on the road report. I may even try a 3.3 cw & p myself at some point.

Hopefully you have not relied on just metal to metal contact to keep the oil in the diff, otherwise you are going to have a very slippery garage floor.

Leslie

[2cams70]

Hopefully you have not relied on just metal to metal contact to keep the oil in the diff, otherwise you are going to have a very slippery garage floor.

Do what the brilliant engineers who designed the diff from a clean sheet of paper did and you won't go wrong.
Fully ready to argue the point more Leslie but I think you've given up!

[2cams70]

Note if you installed new bearings 9 lb inch is not enough pinion preload. Also note that the oil seal drag must be measured with zero preload on the bearings and this figure must be added to the bearing preload spec. in order to arrive at the measured correct total figure (bearing preload + oil seal drag).

Attached are the spec's from the Ford manual

[rgh0]

Hopefully you have not relied on just metal to metal contact to keep the oil in the diff, otherwise you are going to have a very slippery garage floor.

Do what the brilliant engineers who designed the diff from a clean sheet of paper did and you won't go wrong.
Fully ready to argue the point more Leslie but I think you've given up!

Yes
Do what those brilliant Ford engineers did i.e. redesign it a second time to try to stop the leaks and ensure the preload is maintained...... Us engineers never ever make mistakes or do things that are only half good to satisfy accountants and last past the warranty do we?

or.... just use a suitable flexible Loctite anaerobic sealant under the nut and end of the spline. If there is enough clearance in the spline so that sealant will not work due to the splines moving to much, then you need new components and trying to assemble with no sealant will be even worse. Just another humble engineers opinion. I have spent my life discussing this sort of machinery design detail with some of the worlds best engineers and I may be right and I may be wrong. That's life on the internet you have to judge what to believe and what not to.

Incidentally my VW uses O-rings to seal the end of the splines in similar drive flange circumstances, maybe they learned that metal to metal does not stop oil leaks always.

cheers
Rohan

[2cams70]

Yes
Do what those brilliant Ford engineers did i.e. redesign it a second time to try to stop the leaks and ensure the preload is maintained...... Us engineers never ever make mistakes or do things that are only half good to satisfy accountants and last past the warranty do we?

or.... just use a suitable flexible Loctite anaerobic sealant under the nut and end of the spline. If there is enough clearance in the spline so that sealant will not work due to the splines moving to much, then you need new components and trying to assemble with no sealant will be even worse. Just another humble engineers opinion. I have spent my life discussing this sort of machinery design detail with some of the worlds best engineers and I may be right and I may be wrong. That's life on the internet you have to judge what to believe and what not to.

Incidentally my VW uses O-rings to seal the end of the splines in similar drive flange circumstances, maybe they learned that metal to metal does not stop oil leaks always.

cheers
Rohan

Some of you blokes need to lighten up and also open yourselves to new ways of thinking - seriously!!

[Brock]

The tool. (For the uninitiated).

[rgh0]

[
Some of you blokes need to lighten up and also open yourselves to new ways of thinking - seriously!!

An interesting quote from someone who always has to try and have the last word and who has no doubts at all about how correct he is. There is a difference between politely expressing an opinion and just blatantly expressing something as a fact that must be obeyed.

cheers
Rohan

[AshleyPark]

You Aussies, so competitive!

[sabbot]

Thanks guys, I don’t have a rotational torque gauge so had to make do with a digital fish scale and lots of repeated measurements.

[The Veg]

Get a room you guys!