Disappointed... how bad is it? (diff weld)

[PurdueGuy]

Had a machine shop near me weld my diff pin today, and I'm rather disappointed with the results. How bad is it, and are there any instructions I should give the welder if/when I take it back? I know pretty much nothing about welding, but it seems like these are nice looking welds, but with nasty cracks in them. Both sides shown below.

[S.Bretz]

Looks like alot of heat was put in and taken out really quicky.

I would have the welds ground out and reweld it. It looks to be tigged,but not too well. I would just find someone with a 130+ amp mig, I have had no problems with a mig welder and diffs.... only thing is you will have a 'taller' weld that might need to be groud down to clear the diff housing.

[SC2sleeper]

Yeah, What he said........^

[PurdueGuy]

Just dropped it back off at the machine shop - they're re-doing it with a better preheat (and hopefully cool-down), and I'll pick it up tomorrow. No arguments - so far I'm mostly happy with them, just not with the first results...

[TimT]

Might be a little oil contamination too.

Tim

[phat95nosdsc2]

a little [img]{SMILIES_PATH}/smile.gif[/img] tell them to clean it, then heat it first , then weld, then slowly cool it.....or just dont put so much damn heat into it

[BC. Livewire]

you may find that your better off not rewelding that dif

it has gotton to hot to be rewelding it

the parts inside like that big pin may have gotten to much heat thus making it brittel

if your not doing 3 mile long burn-outs than I would bet that those welds will do just fine ( yes I'm talking about the cracked welds )

[ProDarwin]

Be careful with the preheating... you can melt the plastic spacer inside the diff in place.

[PurdueGuy]

Be careful with the preheating... you can melt the plastic spacer inside the diff in place.

Speaking of that spacer... should I be able to see it? I didn't notice it at first, but then I saw it peeking out about 1/2", I think during the time between when I picked up the diff & when I took it back...

[PurdueGuy]

Well... it's bad. I picked up the diff today, again, and the welds were bigger & beefier, and as prodarwin warned about (too late, unfortunately, but thank you still)... they totally melted the nylon bushing inside the diff.

Pictures of welds, and melted stuff:

first weld

side view

bushing sticking out on right, melted badly on left

second weld

side view

other side of the gears

for the heck of it, some light surface rust on top of one of the bearings, due to the axle being out for a while, thus being exposed


I think the bushing was actually melted after the first time, though, and the second time just cooked it further, because part of the bushing was sticking out a bit after the first time.

So....

Q#1 - for future reference, does this weld stick out too far?
Q#2 - if I rebuild this diff ($90 kit includes bushing, diff pin, and the 2 gears on the diff pin), is it still going to be damaged from all the heat that the main diff casting has been through, or is it beefy enough that it'll be fine?
Q#3 - is the surface rust on the bearing a problem?
Q#4 - does anyone have some instructions about how I should tell the shop to do the welding to NOT do this again?
*edit* Q#5 - I have a '97 MP3, judging by the number on the tranny housing - what year/model of trannys have compatible differentials? Will any manual tranny diff work? (I'll be looking around to try to find the ultimate swap guide and answer my own Q, but thought I'd throw it up here, too)

Right now, my plans are to post up WTB threads on the major forums to see how cheap I can get a whole new/new-to-me-in-good-shape (hopefully with already welded diff pin) differential, and compare that with rebuilding mine with the $90 kit from Saturn (they don't sell just the nylon bushing, of course - you have to get the diff pin kit with the bushing & 2 gears along with the pin... and strangely enough, not the roll pin). Tomorrow I'm going to talk to the machine shop and basically let them know how much it's going to cost me to fix it, and let them know the options I'm exploring, and ask them if they think they can weld the diff pin RIGHT if I bring it back repaired, and if they're going to want more $$ for it. My hidden agenda for doing this is to give them a chance to say "we screwed it up, we'll pay for part/all of the repair. I'm not holding my breath on that one, though...

[S.Bretz]

93-03 manual differ shouldbe compatible.

In future cases, just send the diff to me. Just pay shipping and throw me like $10. I will send it back with out a melted' Rockie's Helmet".

I would put a new bearing too.

[PurdueGuy]

93-03 manual differ shouldbe compatible.

In future cases, just send the diff to me. Just pay shipping and throw me like $10. I will send it back with out a melted' Rockie's Helmet".

I would put a new bearing too.

I might take you up on that if/when I find a different diff. Couple of the guys on the SDA forum are questioning the strength of the cast piece after being apparently superheated twice (plus a 3rd time that would be required after dismantle & rebuild), so I'm looking to just get something else.

Anyone want to buy a cool paperweight? [img]{SMILIES_PATH}/evil.gif[/img]