Ah Sh*t. Blown gearbox :(

ScubyRoo · Post by **ScubyRoo** » Fri Dec 10, 2010 7:16 pm

Watch and listen to this:

http://www.youtube.com/watch?v=5ShsKnpaI7c

I've had an intermident whining sound coming from what I thought was the centre bearing of the tailshaft for the last few months. Last week it started getting really loud (like hard to hear my passenger talking at freeway speeds) and this weekend I planned on taking a closer look.

On the way to work this morning on the freeway (or should I say Tollway, being a melbournian) it changed from a whirl to CLUNK! clunk clunk clunk clunk clunk clunk clunk... Pulled over and no sign of leaky oil. Started off carefully with some nasty sounds in first and what felt like clutch slipping. By the time I hit third the sound was gone, and after a few traffic lights with stop starts in first the sound quietened down. Leaving school up the hill in first it felt like the clutch was slipping (new clutch plate ~7000km ago) on take off with some rattle which felt like tailshaft, gone by the time i hit about 20km/h. Quiet ride home with no whirl, no clunking, at freeway speeds. Had a look tonight and saw oil stains at rear diff, centre bearing, output seal, centre diff and transfer case join. Jumped back into the car to go to the local parts joint to get some tranny oil so I could get started. On the way back at the lights I heard what I had only heard previously on youtube (it always happens to someone else, right?) and had that 'oh shit' moment, wondering if I would have to call the RACV only 2ks from home. I had my camera with me and took a video on the drive home so you can share in my suffering.

I have another gearbox already in parts that as a reliable recco'd gen 1 d/r, 3.9. My OBW is 3.7 and a different clutch setup, so I need to pull this one apart and switch the internals and source a new rear diff because 3.7 sucks balls. I've been meaning to put the L-series low range in for a while, so tomorrow i'm off to the wreckers to find the donor box and a 3.9 rear diff. Would like to finally get the 4.11 in but need my car back on the road asap as it's my daily, so see how $$ and time go for sourcing parts.

Cheers,
Owen.

guyph_01 · Post by **guyph_01** » Fri Dec 10, 2010 7:50 pm

Ohhhh, nice noise. Real shame. Let us know how you go with the L low range in the D/R box. I'm plannin to do the same:)

Gd luck with it.

YouTube · Post by **El_Freddo** » Fri Dec 10, 2010 8:45 pm

Rear diff! That's what we've narrowed it down to, about to find out after Owen's drained the oil. Gotta love facebook and skype

Cheers

Bennie

ScubyRoo · Post by **ScubyRoo** » Fri Dec 10, 2010 10:45 pm

Thanks to El_Freddo for our skype conference - gotta love technology these days! I'll let the pics to the talking...

The offender (note the oil on the sway bar!)

Yep, oil all over the joint, with some WD-40 to get things moving:

The drain plug was a bugger to undo - El_Freddo suggested finding someway to stop it from twisting with the torque. So I busted out the jack and there was even a convienent point upon which to jack - it was pretty hard on there - almost enough to lift the car off the axle stands:

Here's the drain plug, with just a small amount of the smashings stuck to the magnet (and no, that long bit isn't a drip of oil!):

The oil that came out (it was clean as a whistle when I checked it a month ago):

2 shots of the mashed up metal that was in the oil (I cleaned the magnet and ran it through the oil after each photo, did it 3 times):

And what the plug is supposed to look like:

I'll be heading to the wreckers to find myself a replacement diff tomorrow, hopefully have the car back on the road by tomorrow night.

Massive thanks to El_Freddo for his help and trouble shooting - couldn't have done it without him. Moral of the story - if you have any strange sounds coming from your drivetrain, check your oils regularly! Still got the other potential oil leaks to contend with but will give the gearbox area a good clean tomorrow to make sure its not just accumulated grime.

Cheers,
Owen.

AlpineRaven · Post by **AlpineRaven** » Sun Dec 12, 2010 9:58 am

Any update on what you've found?
Cheers
AP

YouTube · Post by **El_Freddo** » Sun Dec 12, 2010 10:16 pm

AlpineRaven wrote:Any update on what you've found?
Cheers
AP

Blown rear diff. I'm waiting on hearing if he got another one and got it installed before tomorrow.

Owen: I tried skyping you tonight but you didn't pick up...

Cheers

Bennie

ScubyRoo · Post by **ScubyRoo** » Sun Dec 12, 2010 11:05 pm

Yep, rear diff was well mashed.

Levering off the bearing retainers:

Retainers themselves:

A nice surprise after I had cracked the cover off, the original diff on the right hand side is a vsld! Compare the condition of the teeth on the ring gear :S

After trying without success to put the centre into the donour case, I realised that there was a difference between the two cases:

Now look up at the last 2 photos, and play spot the difference. Remember, they're taking from pretty much the same angle and distance. Hint: pinion gear shaft...

So I went at it with the grinder and eventually it fitted in, but no photos since then. Once it was all in, the whole assembly wasn't rotating properly. After talking with El_Freddo and doing some troubel shooting, we've figured out that a few things are likely causing the roughness: a) worn ring gear from the original lsd not matching the donor pinion gear, b) bearing retainers incorrectly shimmed, c) wrong combination of bearing retainers / diff / casing.

So a bit more trouble shooting to do tomorrow and then hopefully it'll be done.

Cheers,
Owen.

YouTube · Post by **El_Freddo** » Sun Dec 12, 2010 11:10 pm

You'll get there mate - just be patient and you'll be sweet!

All the best!

Cheers

Bennie

YouTube · Post by **El_Freddo** » Wed Dec 15, 2010 9:47 pm

How did you go Owen, all good?

Sorry I've forgotten to jump on skype tonight until now

Cheers

Bennie

ScubyRoo · Post by **ScubyRoo** » Fri Dec 17, 2010 12:37 pm

No photo update as the camera is not at home.

Today the seals and shims finally(!) arrived, 4 days late. In preparation and anticipation I ground the housing out to more easily accomodate installation/removal of the vlsd centre, cleaned and lightly sanded all the gasket/seal mating areas and gave the whole shabang a good clean up.

I had previously just transfered the centre straight accross into the new box, but was not getting proper engagement between the pinion gear and the ring gear. So this morning I swapped the lsd's ring gear to the donour box's and now it all fits together nice and snuggly.

I also read carefully through the factory manual for the reassembly process and found the forumular for measuring and calculating the bearing preload (thus the need for more shims). I'll post up the formular later as a record for anyone else who needs it.

I'm about to smash down some lunch, then its off to get this diff built and installed (with a side trip to bunnings for some hose

).

Cheers,
Owen.

AlpineRaven · Post by **AlpineRaven** » Fri Dec 17, 2010 8:10 pm

ScubyRoo wrote:Yep, rear diff was well mashed.

Levering off the bearing retainers:

Retainers themselves:

A nice surprise after I had cracked the cover off, the original diff on the right hand side is a vsld! Compare the condition of the teeth on the ring gear :S

After trying without success to put the centre into the donour case, I realised that there was a difference between the two cases:

Now look up at the last 2 photos, and play spot the difference. Remember, they're taking from pretty much the same angle and distance. Hint: pinion gear shaft...

So I went at it with the grinder and eventually it fitted in, but no photos since then. Once it was all in, the whole assembly wasn't rotating properly. After talking with El_Freddo and doing some troubel shooting, we've figured out that a few things are likely causing the roughness: a) worn ring gear from the original lsd not matching the donor pinion gear, b) bearing retainers incorrectly shimmed, c) wrong combination of bearing retainers / diff / casing.

So a bit more trouble shooting to do tomorrow and then hopefully it'll be done.

Cheers,
Owen.

I thought it was just me about 3 years ago, i had same number of teeths/ratio but i couldnt mix due different "angle" of the teeth on pinion shaft to match the crown - i was in a hurry that time and didnt really look into that.

With the diff housing - ive done that before - grind it down with angle grinder - that what Subaru did..

So really what caused the problem with the diff dry or not enough oil or wrong oil??
Cheers
AP

ScubyRoo · Post by **ScubyRoo** » Sat Dec 18, 2010 9:03 am

AlpineRaven wrote: So really what caused the problem with the diff dry or not enough oil or wrong oil??
Cheers
AP

Not sure AP. I checked the oil a bit over amonth ago and it was still fairely clean. As there are no markings on the case to indicated that it is lsd, I would hazard a guess that the last time the oil was changed the mechanic simply replaced with the oil what he puts in every other '97 subaru outback, not thinking it might be different because its JDM. I hadn't serviced the rear diff since I had the car, so that is probably it.

Cheers guys,
Owen.