Easy Transmission Front Seal Replacement

[Gloyale]

So, for all those of you who are suffereing from stinky burning gear oil from a leaky input shaft Front seal on the trans, I thought I'd do this write-up.

 

Most tranny shops would chargbe BIG money to disassemble the tranny to replace that seal. Most would not even replace just this seal, they'd want to rebuild the whole thing for like $3000. Not an option for most people.

 

Subaru FSMs show the disassembly as a very tough process, involing removing all the guts of the center diff, etc....ughh.....

 

Thankfully That is not needed to replace the front seal!!!

 

 

*****It's worth noting that I also replaced the front shaft bearing (the one with the dowel) since there had been play on that shaft. The pilot bearing in the flywheel that supports the very front of the shaft had grenaded, so the bearing in the trans was doing all the work. I'm sure it was wobbling causing the seal to go. I believe it was also making for crunchy shifts. It was $34.17, and replaceing it was super easy while apart and made for better shifts.

 

It also would be a good time if one was inclined to replace the diff/axle stub seals, as this way you don't need to remove their retainers or reset backlash. As well the rear output seal and the crush washers for the neutral and reverse switches are accessible and would make for a FULL reseal. *****

 

However this writeup covers only the front seal replacment as it is the only one that HAS TO BE done this way.

 

Here's the skinny:

 

First remove the trans:

 

Next, remove the four bolts on the coverplate on the rear. You'll see the shifter shaft, and teh little arm that locks it into the reverse checker(lockout) remove the 10mm bolt that holds that arm in place, careful not to drop it down in there.

 

Now remove all 8 14mm bolts holding the rear section to the front case halves. Rotate the shifter rod CounterClockwise to disengage it from the forks and then slide off the rear section. This is what you'll see. Take note of how the 3 shifter rods notches are alinged, as you'll need them this way for reassembly. All the slots line up. Here's what the *finger* on theend of the shifter shaft that engages them looks like.

 

Remove the 2 bolts on the right(as installed on car passenger) side in the bearing retainer around the lower shaft

 

Now it's time to open the case halves. Set it on the left side, you'll be lifting up the right half (left half has all the shift rods and forks in it) Remove all the bolts around the edge, and 4 14mm ones that are in the middle, 17 in all. Make sure you haven't forgotten the two that I mentioned above in the rear where the shaft retainer bolts on. Double check that you got all the bolts, and split the case.

 

Here is the seal you are after.

 

Lift out the shaft

 

Slide off the seal, and slide the new one on.

 

Now, there are a few important notes to the reassembly. First, there is a dowel pin in the recess for the bearing in the middle/front of the shaft. The hole in the bearing must seat onto this pin or the case won't go back toghether right.

 

And, at the rear of the shaft, there is a snapring around the large bearing. it only goes about 2/3rd of the way around, leaving an *open* section. That open section must be towards the lower shaft. Otherwise, the ring hits the lower shaft retainer ands again won't seat.

 

Slide this collar back on. It just sits there, and it's pretty obvious which side the bevel goes on.

 

Now bolt the 2 halves back toghether, make sure to use sealant (I used threebond, Grey or black RTV would probably work.) No pics of that, but once it's toghether stand it on end. You'll need to set it on something with a holein it so the input shaft can stick through. I used an old wheel.

 

Now, there is a real tricky part to get the shifter shaft to line up with the selector rods. First, pull all the rods so they are in *neuteral*, the middle notch of their travel. It's pretty obvious when all the slot are aligned.

 

Apply sealant (or a new gasket) to the edge. And get ready to drop the rear section on. Now as you drop the section on, you need to rotate the shifter shaft CC. Then once it's seated, you can rotate it back to where it engages the rods. It's tricky, and I wish I coiuld take pictures but I was by myself. Took me 4 tries to get it right. I kept getting the shaft to far in, and catching behind the openings in the ends of the rods and moving one before the other engaged.

 

Once you think youi've got it, put the interlock bolt back in, then try shifting to all the gears. If you can't get all six positions, remove and try again. It sounds hard, but once you've got it all in front of you it becomes pretty clear.

 

Total cost of seal replacement = $12.77 for the seal and a fraction of a tube of Three-bond.

[EVOthis]

wow....very informative..... thanks for the great write-up!

[lmdew]

Thanks for the effort to put this all together!

[wrongturninwv]

I read your post on front seal replacement. Great info !! I have to do the rear trans seal on a 95 Impreza sport wagon I just picked up for my sons first car. Would like to know what problems I may run into. I know I have to drop the cat converter to remove the heat sheild first. Are there seals between the cat and the pipes ?? And will be able to get at rear seal since it sits so deep in rear of trans ?? thanks wrongturninswv@wmconnect.com

[Gloyale]

I read your post on front seal replacement. Great info !! I have to do the rear trans seal on a 95 Impreza sport wagon I just picked up for my sons first car. Would like to know what problems I may run into. I know I have to drop the cat converter to remove the heat sheild first. Are there seals between the cat and the pipes ?? And will be able to get at rear seal since it sits so deep in rear of trans ?? thanks wrongturninswv@wmconnect.com

 

You should have no problem getting to the seal.

 

I suggest dropping hte exhaust off entirely, just disconnect it from the heads, and hte one bolt at the rear of trans, the rest is held on by rubber hangers that pop off fairly easily, the n the whole shebang can be dragged out fo the way.

 

Not sure but I know on Legacy Outbacks there is a heat shield between the exhaust and the driveline. If the imp has that too it will need to come out.

 

Also,you wil have to disconnect the 2 sections of driveline, and drop the front section out of the way.

[dcarrberry]

Gloyale,

 

I've craked my case open - what is "free play" on the main shaft? 1/8th? 1/16th? 1/32"?

 

 

I had a heck of a noise when the clutch was engaged and in any gear that matched RPM. Sounded like two grinds a second, so maybe every 4 revolutions or so.

 

Best.

 

Dcarrberry

[dcarrberry]

Gloyale,

 

Also, if i wish to do the bearings, can I move the 5th gear and synchros without a press to access the rear rollerbearing?

 

I have the FSM. 1996 2.2 IOBS

 

Best -

 

dcarrberry

[Gloyale]

Gloyale,

 

Also, if i wish to do the bearings, can I move the 5th gear and synchros without a press to access the rear rollerbearing?

 

I have the FSM. 1996 2.2 IOBS

 

Best -

 

dcarrberry

 

Yup, 5th can be pressed off easily. But be careful of the shift collar and synchro set-up. I lost one of the 3 sliders and ended up having to order one ($2.51) from subaru and wait. Then of course I found the lost one hiding inside the cleaned and waiting AWD transfer section. They can really fly if you let em just spring outta there.

[dcarrberry]

Hey Gloyale,

 

I wrote about the rollerbearing on the mainshaft.

 

My question is this: I've got scoring on my rear main plate, the big c plate that holds against that rollerbearing when the transfercase goes on. The scoring is on the two tips that touch the bearing housing on the pinion shaft.

 

I can't get the part til next week, I'd like to get my car running by sunday, how critical is this part?

 

The scoring has broken through the tip layer a bit, and is cracking a bit for about 1/4 inch back along the top. Will this self destruct eventually or just hang out?

 

Thanks -

 

dcarrberry

[lostinthe202]

My question is this: I've got scoring on my rear main plate, the big c plate that holds against that rollerbearing when the transfercase goes on. The scoring is on the two tips that touch the bearing housing on the pinion shaft.....

The scoring has broken through the tip layer a bit, and is cracking a bit for about 1/4 inch back along the top. Will this self destruct eventually or just hang out?

 

Thanks -

 

dcarrberry

 

I don't think I can help you with your question, but I just replaced the rear roller bearing on the mainshaft of my trans (using this writeup as a guide) and I'm curious what you found when you got your trans apart?

 

Also, do you have a digital camera? Can you take pics of the affected parts? That might help asses the damage. Are any of the bearings obviously bad? Like are the cages for the balls all still intact? Do the outer races wiggle, ect?

 

Good Luck!

 

Will

[dcarrberry]

Thanks Will,

 

What I found was the ball bearing gave play to the main shaft, at least a 32nd or a 16th, a good "wiggle". So I decided to replace it as well as the needle bearing in the front.

 

I had to use an impact wrench to get the lock washer off (no problem) and was very careful to keep the synchro group together as one. Then, I used a good little puller to get the 5th gear thrust washer and needle race off, then used the puller again with slight modification to grab way back at the roller bearing. I had the mainshaft in a vice for all this with some wood blocks cut in "c"s to hold it tight, which worked.

 

The roller bearing was tough to pull, and I had moments of lost faith, but I turned the wrench, and it moved.

 

I got it off (the 4th push washer came with it, viscosity I guess, or the way the puller worked) and I found

 

1. the race was loose. Had a good rattle even with some trans fluid still in there.

 

2. The bearings on the blank side (no writing) were scatched and scored pretty bad. 5 out of 7 had the look of - what - really scratched up.

 

Reassured, I reset the 4th thrust washer, ziptied the 4th gear so it wouldn't dance around as I pounded, and set the new roller bearing with some redline assembly goo. It was an impulse buy, it might have worked as well with regular GL-5, but I bought it anyway, after all regular 20w50 is pretty slick in the fingers. I would recommend it.

 

I had to slam that bearing (with a combination of interesting puller hubs as sets) at least 200 times to get it all the way in. I used a 30 or more oz ball peen hammer against the sets (which grew as the bearing got farther on) and interesting, the needle race for the 4th gear started dancing out toward the ball bearing. I had to just have faith and keep going and press it to it's correct position.

 

In the Factory Service Manual, all these bearings and gears are supposed to go on together one at a time with a press, and so I assumed a near stuck fit was necessary, though the 4th gear does need to roll freely and the 4th thrust washer has a little tooth to keep it from spinning, so, I just trusted that the 83 foot pounds on that lock washer would take care of the correct clearance.

 

Anyway, I followed suit with the 5th push washer, needle race (put some greese in the new needle bearings), 5th gear and synchro sleeve set and cleaned the lock washer and bolt with kerosine and then had to tighten the lock washer.

 

Not easy to hold 83 foot pounds with a vice. Had another set of hands with a huge pipe wrench, and the vice, and a good push to get it up there.

 

And that was that. Placed it back in the case careful like, made sure the dowel was down, and then had to replace that back plate. I looked at it and realized it wasn't going to be right.

 

In the FSM, they have two different parts for that, and they tell you to measure the distance the bearing protrudes from the back of the case to determine which to use. It's a difference of thousands of an inch, mind you.

 

But I had a #2, now I need a #1. So I've ordered it and I will be patient. Apparently the difference as to do with manufacturing, plain and simple.

 

I have no url to link to the pictures I have of my plate. Suffice it to say that looking more closely, the crack extends 3/4s of an inch, plus there is wear on the transfer case side. That transfer case side wear would make for more freeplay on the bearing than would be ideal, plus the #2 gave more freeplay anyway, and since my new bearing asks for the #1 plate, that would be double down.

 

There are times for double down, but not on my first transmission rebuild, I feel.

 

Hope this is useful.

 

Best -

 

Dcarrberry

[lostinthe202]

That sounds pretty much like what I did. I have a press at work, but of course it blew a seal the day before I needed it so I just used pieced of pipe and a 5 lb sledge and pounded until the ring of the hammer changed. Worked fine.

 

As for that back plate, hm.... I missed that little detail about measuring for which one you need. I didn't need to replace that plate for it's own sake, it looked brand new, but I don't know if the bearing was different.

 

Ah well, it's back in the car and doing fine so hopefully I got lucky!

 

Will-

[dcarrberry]

I bet you did. the difference in the two plates is literally miniscule. I wish mine was looking good I would have just stuck it in there.

 

Did you replace the little spring pins for the throw-out bearing?

 

And did you replace the Rear Main Seal? Do you know the trick if I want to do it while it's separated?

 

-best

[lostinthe202]

Yes I replaced the little clips that hold on the throw out bearing with new ones from the dealer.

 

As for the rear seal, sadly I did not. I had ordered it, but it went on back order and I really needed to get my car back on the road so I didn't wait. It wasn't leaking before and it's not leaking now, so hopefully I won't have to worry about it for awhile. That and I don't think the trans has to come out to change that seal. Looks like you can just pry it out with some dental picks and press a new one in with a piece of PVC or something.

[dcarrberry]

I read something today:

 

Parkinson's Law -

 

The perceived difficulty of a task increases to fill the time allotted.

 

I'd better get my sweet car back together soon. It's getting silly.

 

Thanks Will.

[Sonicfrog]

Gloyale... I'm gonna try it. I have a bad bearing in my tranny, and I figure the worst that could happen is I screw up, and since the original plan wa to get a new tranny, well, what have I got to lose.

[dcarrberry]

Yeah, go for it. It was easier than I expected. Good challenge.

 

To find out which bearing was bad, wiggled the input and pinion shafts. Mine was the main input rollerbearing. It was obvious from the play.

 

Good luck!

[Fairtax4me]

This is a nice write up. I'll need this if I ever get around to pulling the trans out of mine. That front seal is leaking like a sieve and so is the seal around the shift selector shaft.

[Bash]

Found this post looking fror trans help. can someone put an arrow pointing to where the 10mm bolt is, that needs to be removed to take off the back part of the trans.

Thanks

[Fairtax4me]

It's the small roundish part that's directly under the large cylinder in the pic. That cylinder is the reverse check mechanism. The bolt holds the lever that actuates the reverse checker, so you can't go straight from 5th to reverse.

It's not clear in the pic but you'll see it for sure when you get the top plate off.

[markjw]

Yeah,and it's super tight.At least mine was. Use a quality 6 point socket and stay square to the bolt.You'll be using an extension to reach it,so be careful not to round it off.

[Bash]

Thanks found it.

[Fairtax4me]

Yeah,and it's super tight.At least mine was. Use a quality 6 point socket and stay square to the bolt.You'll be using an extension to reach it,so be careful not to round it off.

 

It is tight, it has thread lock to keep it from backing out accidentally. Be sure to put new thread lock on it when reinstalling.

[Bash]

Has any one used permatex 3h to seal the case?

[samneric]

Excellent write up!

 

I have ordered the front seal for my tranny along with the two drive-axle stub seals.

 

I assume you need to remove the lower shaft and the differential to get at the left hand stub seal - is there any special re-install "gotcha's" about putting the diff and lower shaft back in???

 

Cheers!

 

Steve