|
front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4eat
SVXfiles sent me a genuine Subaru remanufactured transmission to use as a core to do a performance rebuild for one of his customers. I believe it is supposed to be slipping in 4th gear but I haven't gotten into rebuilding the actual transmission section yet. After washing it up and beginning to tear it down I didn't like the wear pattern I saw on the ring and pinion so I decided to re-setup the differential.
It's not very convenient to take pictures while setting up a differential but I set out to do so anyway. I hope the information proves useful. ok so here's the transmission: http://www.subiechips.com/posts/dif/DSC_1889.jpg Here's the ring gear: What concerns me is that the contact pattern goes all the way to the outside of the ring gear (called the heel) and all the way to the edge (called the face). We'd like there to be an unworn edge around the face and the heel. We want our contact patch to start offset to the toe side (ID side of ring gear) and move to the center under load. This leaves an unworn strip all along the toe edge, the face edge, and the heel edge. http://www.subiechips.com/posts/dif/DSC_1909.jpg Here's the pinion: The wear pattern is nice and large but it is shinyest towards the nose of the gear. I'm suspicious this is two overlapping contact patterns from before and after the Subaru remanufacture. http://www.subiechips.com/posts/dif/DSC_1896.jpg |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
The first thing I do is clean the mating edges of the transmission pump and the differential case. After scraping off the ultra-gray sealant and cleaning with a scotch pad surfacing disc I file down any high spots on the differential case mating edge. It turns out there are a handful of them. Anytime you dent a mating surface that metal is displaced making a high spot in the surrounding area. Low spots get filled with sealant. High spots mess up everything.
1st high spot removed: http://www.subiechips.com/posts/dif/DSC_1922.jpg 2nd high spot removed: http://www.subiechips.com/posts/dif/DSC_1923.jpg 3rd high spot removed: http://www.subiechips.com/posts/dif/DSC_1926.jpg 4th high spot removed: http://www.subiechips.com/posts/dif/DSC_1927.jpg 5th high spot removed: http://www.subiechips.com/posts/dif/DSC_1929.jpg Mating flange of differential case in good condition: http://www.subiechips.com/posts/dif/DSC_1931.jpg |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
The carrier with the ring gear on it is suspended in the case between a pair of cup and cone bearings which mate into the side plates. You are squeezing the bearings that the carrier hangs in between the side plates so how far you screw in the side plates determines both the bearing preload and the ring gear's positioning left and right in the case and relative to the pinion.
There is a special Subaru tool for turning the side plates. It would be very near impossible to properly set up a Subaru front differential without this tool. You are actually putting quite a bit of torque on the side plates when you are determining the zero point (left/right placement of the ring gear) and setting the bearing pre-load. Before touching the side plates I mark them and the case with a black marker so I can compare the current adjustment to changes that I make. http://www.subiechips.com/posts/dif/DSC_1939.jpg http://www.subiechips.com/posts/dif/DSC_1942.jpg Driver's side (LH) side plate removed: http://www.subiechips.com/posts/dif/DSC_1953.jpg Repeat on passenger side: http://www.subiechips.com/posts/dif/DSC_1959.jpg You should be careful while doing this not to damage the plastic gears that drive the speedometer. I screw the first side plate back in partially while I flip the case over and loosen the other side so that I can more carefully take things apart. You don't want the carrier/ring gear banging around breaking the plastic gears while you flip the case. |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
With the side plates out you can replace the axle seals. They are pressed in from the inside so they can only be replaced when the differential is being setup.
pressing out an axle seal: http://www.subiechips.com/posts/dif/DSC_1964.jpg axle seal after being pressed out: http://www.subiechips.com/posts/dif/DSC_1965.jpg pressing in a new axle seal: http://www.subiechips.com/posts/dif/DSC_1970.jpg new axle seal pressed in: http://www.subiechips.com/posts/dif/DSC_1974.jpg http://www.subiechips.com/posts/dif/DSC_1978.jpg At this point you remove the o-rings from the outside of the side plates. You put them back on after setting up the dif |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Use brake cleaner to clean the oil off the ring gear and use petroleum jelly to lube the bearings and the plastic gears that drive the speedometer. Also use petroleum jelly to lubricate the side plates.
http://www.subiechips.com/posts/dif/DSC_1983.jpg Carefully re-install the carrier assembly into the case leaving the driver's side side plate out a little further than it's previous location based upon the markings we made before taking it apart. It's time to bolt the pump which the pinion is mounted in to the differential case. You need to actually bolt it to the case. Washers have a crown to them. Be careful to orient the washer so the crowned side faces the pump/case so the outer edges of the washers don't scratch the pump. There's a special Subaru tool for turning the pinion which you'll see in my pictures but you could get by with a big wrench for this one. http://www.subiechips.com/posts/dif/DSC_1991.jpg To find the left/right positioning of the ring gear we tighten the driver's side side plate until the pinion won't turn any more. That is called the zero point. Then we back the driver's side side plate out 3 notches on the side plate. I end up with the driver's side plate one half notch further in than the last rebuilder did so I have less backlash. http://www.subiechips.com/posts/dif/DSC_1995.jpg To set the bearing preload we tighten the passenger side side plate until it stops turning, back it off, tighten it till it stops turning again, back it off, ...repeat..repeat, tighten it till it stops turning(meaning that it stops turning using the tool with one hand)...then tighten it 1 and 3/4 notches further using both hands. I end up 3/4 notches further in than the last rebuilder did so I have more bearing pre-load. http://www.subiechips.com/posts/dif/DSC_2002.jpg |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Now it's time to check our contact pattern. So we unbolt the pump from the case and paint some gear matching compound onto the teeth of the pinion. The ring gear is still clean at this point.
http://www.subiechips.com/posts/dif/DSC_2011.jpg http://www.subiechips.com/posts/dif/DSC_2012.jpg Then we bolt the pump back to the case and give the pinion a few turns forward and a few turns backwards. Then take the pump back off to see what we have. The contact pattern on the ring gear is much better. We've moved well in from the face edge towards the center of the teeth leaving matching compound on the face edges. It's offset to the toe side now and under load will move towards the middle without making it all the way to the heel. Between removing the high spots on the mating surfaces and decreasing the backlash we've gotten to a much better place. I think I can still improve the pattern on the pinion. I'd like to move it in more in both directions and make it as big as possible. http://www.subiechips.com/posts/dif/DSC_2016.jpg http://www.subiechips.com/posts/dif/DSC_2017.jpg To move the pattern from the toe side of the ring to the center (when the carrier's left to right position is set right) we want to reduce the thickness of the pinion shim/shims. Time to remove the seal retainer from the pinion/pump and then the pinion itself to pull out the existing shims and see what we have. In this case we have two shims which I measure with a micrometer. I get a measurement between in inches between the .15mm and .175mm which is the closest thicknesses they come in--so we have a dirty pair of .15mm shims. I was going to replace them with a single .2mm shim but it was rusty so I went with a .225mm shim. http://www.subiechips.com/posts/dif/DSC_2055.jpg http://www.subiechips.com/posts/dif/DSC_2058.jpg http://www.subiechips.com/posts/dif/DSC_2061.jpg |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
With our new shim installed we will have to redo our side plate settings before checking the contact pattern again. We have to loosen our lh retainer before installing the pump then redo our finding our zero point setting our lh retainer then setting our bearing preload. Then we take it apart again, re-apply our matching compound, put it back together again, give it a few turns forwards, give it a few turns backwards, take it apart again, and see what we have. It's much better. It's good even. The pattern on the ring gear has shifted towards the middle and gotten bigger. We want the pattern to be a little towards the toe side like it is. Under load it will shift towards the heal. The pattern on the pinion has shifted towards the middle and gotten much bigger.
http://www.subiechips.com/posts/dif/DSC_2063.jpg http://www.subiechips.com/posts/dif/DSC_2068.jpg http://www.subiechips.com/posts/dif/DSC_2074.jpg |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Double checking the setup after finishing up it looks good. We've got good size contact patterns on both the forward and reverse sides of the teeth. On the ring gear the pattern on the forward side is a little offset towards the tow edge and the pattern on the reverse side is offset a little towards the heel. Under load the contact patch will move right to the center.
http://www.subiechips.com/posts/dif/DSC_2153.jpg http://www.subiechips.com/posts/dif/DSC_2160.jpg |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Excellent write up! Shame OT didn't send you a LSD for the front diff!
|
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
|
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Should be PDF'd and put in the how to section. Thank you for taking the time to write it up and for sharing.
|
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Thanks, and thanks for sharing the link Tapani. Now someone wanting to get a front lsd can both find the part and get an understanding of how it installs.
|
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Quote:
I bet the effect is even greater with the MPT tranny. /T |
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
Quote:
|
Re: front differential setup how to and re-rebuild of genuine Subaru Remanufactured 4
shouldn't be
Quote:
|
| All times are GMT -6. The time now is 09:58 PM. |
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2024, vBulletin Solutions, Inc.
© 2001-2015 SVX World Network
(208)-906-1122