Swapping diff crown gear.
 

Right here is my dilemma.

I have removed a gearbox and diff (TY754VB1AA 4.111), and replaced it with another (TY752VBCAA 4.444).
The old driveshafts will not fit the new rear diff as there is a bar inside where the driveshafts go in, so the old shafts are too long. And I want the car to go to a Car Show on Bank Holiday Monday, and then Japfest next weekend. I will be having a matching set of rear shafts arriving next week, but I`m not 100% if they will fit my hubs, so would need removal of the inner parts and fitting to the outer parts


If I call the old diff A and the new one B.

Can I remove the diff and side bearings and shims from A, and fit into B using the case and Crown gear from B?? This would allow me to get the car finished today so I can use it this weekend. But I don`t want to mess it up, so it becomes a problem.

Use these from Diff A
http://i159.photobucket.com/albums/t...318800x450.jpg

http://i159.photobucket.com/albums/t...316800x450.jpg

And fit to these from Diff B.
http://i159.photobucket.com/albums/t...317800x450.jpg

http://i159.photobucket.com/albums/t...320413x800.jpg


Basically will this be a straight swap or am I best of forgetting it and biting the bullet and waiting for driveshafts to come (Which again may not fit my hubs).



This is the problem.

Diff A.
http://i159.photobucket.com/albums/t...309800x450.jpg

Diff B.
http://i159.photobucket.com/albums/t...311450x800.jpg

Any one??

I don`t know whats going on with this rear diff tbh, as far as I can tell they are r160 shafts, but they won`t fit.

This is what I can find are the correct shafts for the TY752VBCAA box that is fitted.
http://i159.photobucket.com/albums/t...x/resize-1.jpg

Note the longer end on one, well this is what my shaft looks like.
http://i159.photobucket.com/albums/t...335800x450.jpg

Exactly the same. BUT for some reason the shaft cannot go into the diff due to the bar in the way also there is no second narrower set of splines like on the WRX plated diff.

If you look here you can see it.
http://i159.photobucket.com/albums/t...337450x800.jpg


So from having a quick measure up it looks like I should have this much removed from the shaft, so making it identical to the passenger shaft.
http://i159.photobucket.com/albums/t...35800x450s.jpg



What diff is this I have?? As its VERY strange!!

Sod it, I need the car to be used so am going to attempt the swap.

My thinking is that as long as the crown wheel has the right amount of teeth, and I use the matching parts of the diff like the shims and the bearing outer halves.
Then it should be ok. As the bearings won`t be moved, so the lash should be the same, and the preloading will also be the same as I`m using the matching shims.

Right I`m soooooooooooooooooo glad I took apart this so called FCUKING 4.444 rear diff as its an OPEN diff!!


39 teeth on the crown wheel, 11 on the input shaft.
So 39 / 11 = 3.545 NICE!!
Even has 39:11 stamped on the diff.

http://i159.photobucket.com/albums/t...340450x800.jpg

http://i159.photobucket.com/albums/t...341800x450.jpg

http://i159.photobucket.com/albums/t...342800x450.jpg

http://i159.photobucket.com/albums/t...339800x450.jpg

http://i159.photobucket.com/albums/t...338800x450.jpg



So this thread is all bloody academic now as the diff will NOT fit the gearbox I was sent, YEE FCUKING HAAAAAA!!

I refurbed a month or so ago a 4.44 vc lsd r160 but i couldnt make hybrid shafts to fit my r180 rear end so is spare.

edited as i was wrong, that is open.

Yeah I see your problem. The ratio thing is one side of it.

The other side is the various internal diffs that are fitted, they can be free, viscous or plated as far as original Subaru are concerned. Then depending upon the type and style of LSD have either 2 same length shafts, One short shaft & one long, OR then internal or external circlips on the splines to keep them located. The shaft in the middle of the slip deal is a plated type [ P1 by the look of it ] . The hole through the middle can mean either open or viscous and the giveaway is the twin spline thing. One shaft needs to have twin splines on a viscous to make the thing work.

The shaft with a taper at the end is usually the one for internal circlips [ inside the diff ] as it needs the lead to engage them or the clip gets pushed off.

But people get confused [ as you probably are now ] about whether the diff needs internal or external circlips when they find a gap where they think a clip should be.

Best to call some one like us, have a picture of the shafts you have and we'll try to build a diff that uses whichever shafts you have - to save buying any more.

754 VB1aa is a 4.4 rear diff type.

David APi

01926 614333

Thats the diff I have just taken apart, and according to the crown wheel its a 4.111 using the teeth on the input and crown gears.

Apologies, you are correct, the VB1AA is from the 99-00 WRX wagon and is a 4.111. So you need a 4.111 rear diff to match - R160 size.

Apologies for the wrong info, David

It's not been explained well Tbh so here goes. My car had a TY752VB3FA fitted when New. That went through oil like George best went through alcohol. Was replaced with a TY754VB1AA as an upgrade. This stripped 3rd then I bought a replacement box which when sent was wrong, so they sent a TY752VBAAA with matching diff as a replacement. Upon fitting the gearbox the rear diff didn't fit the shafts so I put this thread up asking if i could swap the crown wheels on the diff so that this New 4.444 diff would fit my shafts. But after opening up the New 4.444 diff I found out it wasn't what I needed But a 3.545 open diff. So making this thread academic.

Ah ok., so you're sorted then? Just a shame really as the 752 VBAAA is a real oldie and probably won't last long. You'd be better off getting the VB1AA fixed as that is the strongest one in your ' fleet '

Good Luck, David

Thats the plan, but not decided on which route to go down.

The VBAAA should do for now and is more period (not that it matters).