do you have a welded front/rear diff, did you pre-heat?

It's been awhile since I posted last, but after a good day in the woods of Ojibwe Forest Rally, smoking some of that rally crack to feed the addiction, I decided to dust off the '91 legacy 2wd drive and weld that front diff. I've been talking about doing for the last 5 years....

so a few questions to the welded diff owners/makers of weld...

1. did you or your friend pre-heat their diff before welding, if yes to what temp?
2. are there any hidden do-hickies/springs/pins that will drop out of the trans case while I'm splitting it and fall to the floor just before I can see where they came from?


-Richard

1. No, it's not really necessary to preheat. Make sure you have axles (or spline stubs in your case) inserted into the side gears while welding or you'll never get them back in again. Weld everything to everything. (well, don't weld the pinion to the ring gear, duh, but you get the idea.)

2. What the hell are you doing splitting the case apart while holding it over the floor? Seriously though, if you've never taken a Subaru transmission apart then I urge you to get a factory shop manual for guidance first. There are pins that locate the input shaft and pinion shaft bearings that will fall out of the case if you invert it with the gear clusters out but there is no reason for you to do that. You will have to pull the clusters to remove the diff and the most common mistake I see is not getting the hole in the pinion bearing lined up perfectly with the locating pin. When that happens you squish the pin into the case and misalign the bearing slightly.

I didn't preheat my diff, and it seems to be holding up just fine.

I've taken a Subaru tranny apart before, and if I were in your shoes, I'd just weld the center diff and make it RWD.

Doivi,

Thanks for the tips! I'll pay attention to the pins, but it brings up my next question.
With the suggestion of not inverting the case while the cluster is out. That gives me the impression that I should be working from a common side.

What half should be laying on the bench? driver or passanger side?

As for holding one case half in each hand while welding with my feet.....
Garage God rule 153 "If something has the ability to lose its self during disassembly it will lose its self in the darkest greasiest part of your shop." and this rule usually is preceded by Garage God rule 152 “When working on metal bench, metal parts will bounce and are subject to ‘Garage God Rule 153’.”....like you said, but seriously, I really enjoy this sites moderator to poster dynamic. I'll post pictures when I do the dead.


Sureshot007,

I would, if I had a center diff.

Quote
Richard Donovan
Doivi,

Thanks for the tips! I'll pay attention to the pins, but it brings up my next question.
With the suggestion of not inverting the case while the cluster is out. That gives me the impression that I should be working from a common side.

What half should be laying on the bench? driver or passanger side?

As for holding one case half in each hand while welding with my feet.....
Garage God rule 153 "If something has the ability to lose its self during disassembly it will lose its self in the darkest greasiest part of your shop." and this rule usually is preceded by Garage God rule 152 “When working on metal bench, metal parts will bounce and are subject to ‘Garage God Rule 153’.”....like you said, but seriously, I really enjoy this sites moderator to poster dynamic. I'll post pictures when I do the dead.


Sureshot007,

I would, if I had a center diff.

That's why you're 'spossed to use tiles at least up to chest level. What tile.
Lots of big lights everywhere and the garage should be able to double as a "Clean Room".
Finally you have to work in strict silence so when the stupid circlip goes PIIIIIIIIiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiinng _{ding ding}
You hear exactly where it landed, walk over and pick it up and start over.

I suggest that you study the great films of "Zatoichi" the story of the wandering blind masseuse and gambler.
If you going to be living where evil is everywhere---like the common garage, you better atune your senses!


I've seen this guy slice a coin flipped back at him (when he was paying for a cheap rice-ball with a big gold coin---a trick to get the rice-ball free cause the guy would be unable to make change), using the sopund alone to carve off onl;y a sliver---which landed right in the coin box while he caust the rest..
Train to that level and you'll always know exactly where things went flying.

(And watch the movies and you'll have a good time)

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.



Edited 1 time(s). Last edit at 08/27/2012 04:19PM by john vanlandingham.

Quote
Richard Donovan
Doivi,

Thanks for the tips! I'll pay attention to the pins, but it brings up my next question.
With the suggestion of not inverting the case while the cluster is out. That gives me the impression that I should be working from a common side.

What half should be laying on the bench? driver or passanger side?

Driver side on a LHD car. But if you got a factory repair manual it would tell you that. Hell, you can probably download one off the internet.

Once out, thoroughly degrease the diff and give it a good rinse with acetone. By tig welding the
FWD Impreza diff it was easier to avoid getting splatter where it shouldn't be. You're essentially creating a
big, ugly spool. The whole diff will heat up quickly as you keep welding. It will take overnight to cool. Don't
rush it. And avoid doing the dead thing.
JT

I'll avoid the dead while I'm doing the deed this weekend...but I'll still take pictures.

I'm using a gas shielded mig welder with 0.30 wire, but could pick up 0.35 if urged too.
I wish I had two diffs, so I could try pre-heat and not pre-heated...I might try pre-heat for fun and wrap in insulation for a slow cool down or maybe just because I have too much free time.....

I'm mainly curious to see if I'll get a better cleaner weld with the diff pre-heat to 450 degrees.

Pre-heating is beneficial to guys with less powerful welders. If you can crank up the juice it's not all that necessary in this situation.

Quote
b00sted
Pre-heating is beneficial to guys with less powerful welders. If you can crank up the juice it's not all that necessary in this situation.

And 035 wire---you can get 2lb spools---is one way to do that.

---

John Vanlandingham
Sleezattle, WA, USA

Vive le Prole-le-ralliat

www.rallyrace.net/jvab
CALL +1 206 431-9696
Remember! Pacific Standard Time
is 3 hours behind Eastern Standard Time.

Quote
john vanlandingham

Quote
b00sted
Pre-heating is beneficial to guys with less powerful welders. If you can crank up the juice it's not all that necessary in this situation.

And 035 wire---you can get 2lb spools---is one way to do that.

Yeah, like I said in this case it really doesn't matter what you do. It all works. I've seen guys do some pretty hoaky stuff when it comes to welding diffs.

Preheating becomes necessary when welding thin material to much thicker material...Such as .090 wall tube braces to a diff housing, welding a v-band to a turbo compressor housing, etc. I'm not much of a welder, but this is just some of the little tidbits I've picked up over the years.

Good point about heat penetration when welding thin to thick material. Since I'm not adding shims and only welding it, I'm sure it will turn out fine. Even though my inner geek really wanted to try it.

With the trans out I'll be playing around with the shifter throw geometry too.

Does anyone have any super awesome secret transmission tips/tricks to preform while I have it apart???



JVL, I'll pick up some 0.035 flux core wire. So by now you've probably guessed that I'm not trying to push 0.30 wire through my MIG welder like my previous post suggests........ Had to type quick since I was at work....

Top tip for people that drop things all the time (like me). I started to litter my shop with anti-fatigue mats. An added bonus was that when I drop small items they are caught in the holes. cant tell you how much time it saves. Just clean "under" the mats often.

---

Intercom and electronics dude. www.zerodegreec.ca

Splitting the trans was easy and fun. Welding the diff was easy too. I cleaned it in the parts washer and then gave it a quick break cleaner spray then washed it and blew it dry with compressed air. I had no problem getting it hot enough and was able to get good penetration on the spider gears.

I have attached a few pictures to help other visualize some of the key parts that waned to remove them self from my work bench prematurely, but it was less than expected.

One was a c shaped spacer on the tail end and the other was shift arm connecting to the main shaft also in the tail end. Other than that super easy.

Do I need to weld more?

I'll have to go to a computer to resize the photos sorry guys.....

For future reference: Brake Cleaner + Welding = no-no. http://weldingweb.com/showthread.php?t=32501