I purchased a used diff with a hardtopguy installed comptech reinforced diff and 4.56 gear. I have never handled a diff, so I did not know the play I noticed was 'bad'. I took it to the honda tech for install and he said there should not be any play.

The play I am discussing is about 1/4" movement in and out of the part in the front of the diff that bolts to the drive shaft.

The tech said he could not tighten it because the crush washer may not seat correctly. the gear would have to be rebuilt because that lock nut is one of the first things to get tightened down.
I searched, found threads about diff play and slack, but none of them really answered my questions:

What woud cause this to loosen, because I am pretty sure HTG installed it correctly?

Should I be worried about the gears damaged already, the guy I bought it from said he took it off his car just like that and shipped it.

Does the diff need to be rebuilt?

 

1/4" sounds about right to me. What does a honda tech know about building diff anyways?

OEM backlash = .003
4.56 backlash = .008

So there will be more movement in the input shaft when NON OEM lash is spec'ed.

 

kinetica Posted on Feb 20 2007, 01:37 AM
Do you mean turning?
As in: you turn the part that bolts to the drive shaft (companion flange) and it takes 1/4" of rotation for the output shafts to start turning as well?

In that case I fully agree with Stratocaster.
All normal

If you mean you are able to pull the companion flange out of its housing 1/4" and then push it back in ... you're in trouble and it should NOT have ANY play in that direction.

This is correct: when you are building a diff and starting with an empty diff housing that is the first you do.
Set the pre-load on the pinion bearings with the crush sleeve & companion flange & locking nut.
This has nothing to do with backlash though.
Backlash is set later when the Torsen is in its bearings.

Let us know what kind of movement you are talking about.

 

Yep, this is the play I was talking about. It does have a little rotational play, but the concerning thing is the in and out play.

So what is wrong with it?

 

This is not good!

I would get in touch with the person you bought the diff from and tell that person the diff has to be opened up (on their expense?) to see whats going on.

Worst case scenario is that the final drive is toast.

With play in-and-out the pinion will be drawn into the ring gear while decelerating (engine braking, down shifting) and this is not good.
I can't see any play in just the companion flange while not creating play between the pinion gear and its two bearings.

Best case scenario is that you just need a new crush sleeve (or crush collar = same thing), a new locking nut and a new pinion seal and the pinion has to be installed and pre-load set properly again.
Those 3 parts are not that expensive.
To do that the diff has to be opened up as your tech allready suggested.
I'm sure the tech has an official Honda service manual where that procedure is explained very well.

Since the original install was done by hardtopguy I have no doubts the pinion depth was properly set.
So there is no need to remove / replace pinion bearings.
Backlash has to be set again when putting the Torsen unit back in.
This requires no extra parts, just tools & time.

Open it up to see what's going on is my advice.
Take & post pictures if possible.

Succes!

 

Ouch. I am taking it to a gear shop today and will let you know what they find. Hopefully it is the best case...

 

Took it to a gear shop, he tightened the lock nut and played around with it to see if it needed to be taken apart. He said it was all in good order because he has built so many that he could 'feel' if anything seemed wrong. He said it was great, took the lock nut off and added locktight and put the nut back on.

I asked repeatedly about the backlash and crush sleeve needed to be fixed, and showed him the posts and pms I got from the forums, and he confidently assured me that everything is OK. So now it is back at Honda getting installed. I guess we will see what happens during the test drive.

 

It runs great! of course I need to adjust my yellow box because I was blowing by people on the freeway and my speedometer said 60mph. I was at 70mph at 5000.

It does whine more than I imagined but not unbearable.

 

I would have opened it up to look at the gears teath surface.
All that takes is some new liquid gasket.
(as the tech that can "feel" if a diff is right knows.. no doubt )
Its also possible to see the ring gear through the drain hole.

Just tightening the locking nut is IMO tricky as you dont know at what kind of pre-load the pinion bearings are set.
It may be right (and I hope for you it is!) .. it may be wrong.

Did you put fresh oil in?
If so what kind of oil.

What I've been reading here about the new 4.56 gear sets is that they almost not whine, at least a lot less then the "old" 4.57's and 4.57R's.

Do you have the new 4.56's or 4.57?
Yes, there is a difference.
4.56 = 9 : 41
4.57 = 7 : 32

I hope it all works out for you.
Gears are FUN! to drive.. aren't they?

 

After reading all the threads about gear whine, I dont think mine is different. They must be the older version.

And they are awesome to drive, 3rd gear pulls...wow.