pinion gear replacement

92_LSL · #1 08-13-2011, 05:16 PM

Is there a how to document for pinion gear replacement?

1986nate · #2 08-13-2011, 08:08 PM

On the front or rear diff?
I really need to do one for the front diff for people. Also, you're replacing the ring gear ass well, correct? THey are machined as a matched set and should be replaced in pairs.

92_LSL · #3 08-13-2011, 09:22 PM

Yes I'm doing the front diff, can someone get me a write up on it?

1986nate · #4 08-14-2011, 12:32 AM

Alright, I might miss a couple things,
basically, to get the front carrier case off,
Remove all 14mm bolts/nuts that connect the case to the pump
remove the 14mm bolt from the side plate if it is still holding the transmission lines on
carefully (using a rubber mallet preferably) hammer the front diff forward to break it free and remove it from the rest of the trans assembly

Now, for the extension housing
remove all 12mm bolts holding ext housing onto rest of trans assembly,
remove 10mm bolt holding VSS1 and remove VSS1
carefully remove the ext housing, either using a rubber mallet on the driveshaft "shield" or on other spots to try and get it to break free. Then it should come off fairly easily once the seal is broken.
-Take note, you will have to carefully unclip the small 2 wire harness for the C solenoid and also take note of how the Parking prawl and spring are held in place.
Remove the transfer clutch pack assembly and tailshaft along with the ext housing.

The pinion shaft gear is held on the front of the oil pump by four, 14mm bolts, remove those
-can be done with hand tools, but an impact will make this much easier
Now, on the rear of the trans, it is held on by a 36mm Stake nut. This, without a doubt, you will need an impact for.
Once that is off, make sure you pull any washers off the end of the shaft so they don't end up inside the trans, and you're done with disassembly.

Reassembly with new parts is pretty much the opposite.
I meant to take pics the last time I tore into a trans but didn't have a camera with.
Hope this helps, more than likely I forgot something, so please feel free to correct. I've just done this so many times that I may be forgetting something.

1986nate · #5 08-14-2011, 12:50 AM

some pics to help guide you(I will update when I get better pics)

Lower right gear, normally there will be the pinion shaft coming out the back, held on with 36mm stake nut
(also to note, this is a FWD transmission, notice the bearing on the top gear instead of the transfer clutch gear)

This shows the bolts needed to remove from the oil pump housing to remove the pinion shaft gear

Hope this helps a bit.

Hocrest · #6 08-14-2011, 05:07 AM

Make sure you get new seals or you're going to be doing the whole thing again in a few weeks...

- front and back seal on the pinion plate
- torque shaft tube
- input shaft seal

longassname · #7 08-14-2011, 06:50 PM

Differentials need to be set up. You need the dealer tool for adjusting the side plates, a good dial indicator set, gear die, and an assortment of pinion shims on hand.

You have to take the pump off the transmission as well so you can install it onto the differential and turn the pinion while setting up the dif.

The FSM has detailed instructions. For people who don't have the tools and experience it's usually easier and less expensive to buy a new transmission.

1986nate · #8 08-15-2011, 09:07 AM

For reassembly you need to check the backlash of the gears and add/subtract shims if needed(best done by a differential shop but can be done yourself if you know what you're doing). (forgot this in my write up)

I have done at least 4 differential changes similar to this and logged plenty of miles including over 13k on my laguna after I changed out the differential in a FWD meaning it receives even more stress than an AWD so if something was set up wrong, it would show it's face at this point.
And when using used parts, changing a differential yourself is 50x cheaper than a new trans.

longassname · #9 08-15-2011, 09:52 AM

Nate, I understand a lot of SVX owners are broke and can not afford to properly service their cars so sometimes one has to settle for what they can afford to do instead of doing things the "right" way; however, there is still a reason for doing things the right way. That's why it's the right way. If everyone starts doing things the wrong way then they are just passing on their problems to the next owner and degrading the quality of SVXs out there.

The fsm describes a particular procedure for setting up the diferential for a reason. These reasons apply to you to. If you've done five difs like you described then there are 5 more substandard SVXs out there now. You have to follow the factory procedure to get a factory quality result. If you don't set up a differential right even if you don't get immediate noise you get long term wear and vulnerability to breaking teeth. I'm seeing more and more worn and broken differentials just for that reason--people are putting these things together like you are describing and they work for a year or two before they break.

The shim isn't used to adjust backlash. The shim is used to adjust tooth contact between face and flank. Backlash and preload is adjusted through the side plates This adjusts tooth contact between toe and heel.

Propertly set up SVX ring and pinions don't break. Pictures like you posted above of pinions with the teeth broken off are because someone already put it together wrong. Taking that particular picture/pinion for instance. The wear pattern clearly indicates that the tooth contact was WAY too much to the face.

1986nate · #10 08-15-2011, 11:09 AM

...............

92_LSL · #11 08-15-2011, 11:59 AM

Fu*k this!!!!
I pay $150 for any tranny I want. I'm gonna get another 4.11, these POS slush boxes aren't worth rebuilding.

92_LSL · #12 08-15-2011, 12:01 PM

And nate, thank you for the write up. I'm still saving this for future references.

oab_au · #13 08-15-2011, 05:54 PM

Quote:

Originally Posted by longassname

Nate,
Propertly set up SVX ring and pinions don't break. Pictures like you posted above of pinions with the teeth broken off are because someone already put it together wrong. Taking that particular picture/pinion for instance. The wear pattern clearly indicates that the tooth contact was WAY too much to the face.

"Propertly set up SVX ring and pinions don't break."

In that case, the factory must have set up a lot of front diffs wrong.
No AWD no front diff.

"The wear pattern clearly indicates that the tooth contact was WAY too much to the face."
What wear pattern???

That failure is the result of shock loading that has distorted the case, to allow the crown wheel teeth to move away from the pinion teeth, breaking them off. This happens when the car looses the AWD ability, and the open front diff is excessive loaded by wheel spin.

Harvey.

longassname · #14 08-15-2011, 06:26 PM

Actually we went well past 15 years with complaints of ring and pinion failures an extreme rarity. Then in the last few years since a handful of people started messing with them they have become more regular. It's not because of wear either. I've rebuilt a lot of SVX transmissions and most of them show essentially zero ring and pinion wear. Like I said before a properly set up SVX ring and pinion will last forever. Ocasionally I get a core with a broken ring and pinion. Every single one of them has been on a rebuilt transmission were the differential set up has been botched.

The wear pattern is clearly visible. You can see the bright silver wear out on the face of the teeth and the yellow oil staining on the shank. It is glaringly evident to anyone who has ever done any gear matching. It's not because the case is distorted it's because someone set it up with the tooth contact way too face. The toe to heal alignment is probably off too but I can't clearly see that in the picture since most of the heel is gone. When a diff is set up wrong like this the the contact points between the gears are smaller, located in a weaker part of the teeth. That is compounded with excessive lash allowing a shock between the gears so everytime the load changes direction the gears bang together at their weakest spot.

You can get in a car with the diff set up wrong like that and it drives fine and you're tempted to think "ha see I didn't need to follow those pesky service manual instructions" and pat yourself on the back. Then one day you put it in park on a steep hill and let off the brake or put it in park while it's still rolling a little bit and crack--blown dif.

Quote:

Originally Posted by oab_au

"Propertly set up SVX ring and pinions don't break."

In that case, the factory must have set up a lot of front diffs wrong.
No AWD no front diff.

"The wear pattern clearly indicates that the tooth contact was WAY too much to the face."
What wear pattern???

That failure is the result of shock loading that has distorted the case, to allow the crown wheel teeth to move away from the pinion teeth, breaking them off. This happens when the car looses the AWD ability, and the open front diff is excessive loaded by wheel spin.

Harvey.

1986nate · #15 08-17-2011, 07:52 AM

I deleted my previous post because I don't have the time to argue. All I can say is, before I decided I'd be selling the laguna, I was not gentle with it at all. Granted, I wasn't doing all out burnouts with the e-brake engaged and being a phuctard, but I would have some fun with it.
The original diff in it failed with 93k miles and I purchased it that way. I've replaced it and put over 12k miles of "enjoyable" driving of all sorts, including winter driving. There are no issues with it, nor have their been. Clint (Subix) is buying this car and I will be delivering it next week. If he ever has an issue with it, I'm sure that I'll be the first to know about it. Whether it be a month from now, or 4 years down the road, or even longer. Every differential I have seen failed has been either original or a Subaru remanufacture transmission assembly and actually, all but my laguna and the sheered reduction gear I have pictured below, were AWD transmissions.
1 simple question I have... If a subaru dealership is actually having to replace a differential, do you really think a "rate paid" mechanic is going to go through every single step properly???