Bellhousing keeps cracking!!!

[Hesh724]

For the 3rd time now i have found a crack on the top of the trans bellhousing. The First time I pulled the trans and replaced the T/B and both transmission dowl pins and couldnt feel any lateral movement in transmission output shaft. the crack was V-ed and Tigged both inside and out. And after a few months i had to have the trans weled again about a week ago and after a few days i noticed the first weld was starting to crack again. what else can i try? oh and solid motor mounts and trans mount.

Any Ideas would be great!!

Thank you

 

[bryanwheat]

Was a chunk broken off? Did you weld the it with the transmission bolted to a block?

 

[codeofdastreets]

What pressure plate are you using?? I"ve heared stories of the act 2900 pp cracking bell housings.

 

[donniekak]

Do you have both dowels, and the m8x1.25 bolt that goes through the block into the trans?

 

[bastarddsm]

The first trans I had on my car was cracked and welded around the vent holes before I got it. After the first season of 11sec passes, it was cracked again. Aluminum is dead soft when its welded and not heat treated. It's just gonna keep cracking.

 

[fun kart kid]

Also you have to drill holes in each end of the crack or it will keep cracking. This something I was told in welding class

Sent from my PG06100 using Tapatalk

 

[Hesh724]

Thanks for all the replies. i am using a sounthbend sxs Pplate. I do have both dowl pins in and they are newer ones so they arent coned off on the ends and when the first crack occured i did pull the trans and had it tigged inside and out but this time i just had it welded still in the car it was the top front bolt tab and completly cracked off. if it werent for the bolt i would indeed be missing a part of my trans. i am wondering if it is a mount issue?

Do you have both dowels, and the m8x1.25 bolt that goes through the block into the trans?

The one where the bolt goes through the one dowl pin in the back is missing cause there metal is broke off back there. sadly

 

[BogusSVO]

The solid mounts would be a good start, they pass along the vibration.

What engine mounts do you have? If they are not solid mounts, that is your problem. The engine can move and the trans can not match the movement.

So if you have poly engine mounts, install poly trans mounts.

or since you have solid trans mounts, install solid engine mounts.

But the moral of the story is.... both the engine and trans mounts all have to be the same type!

 

[SkyGrowsCold]

Also you have to drill holes in each end of the crack or it will keep cracking. This something I was told in welding class

Sent from my PG06100 using Tapatalk

You definitely need to drill the ends of the crack or cracks before repairs as stated above. This is important because if you just groove and weld it the crack will eventually come back to haunt you. Drilling the hole helps put an "end" to the crack so it does not continue on its path. You can usually see this when grinding away material that has a crack in it. If you grind past where the crack looks like it ended, in more cases that not, you will see that it actually continues just past where it appeared to end. Same thing applies to stopping a crack in plastic (oh the good old days of motocross quick plastic repairs and "stitching stunt bike fairings back together).

 

[ramsack]

The one where the bolt goes through the one dowl pin in the back is missing cause there metal is broke off back there. sadly

It's probably going to keep breaking then. I've seen all the 10x1.25 bolts keep coming loose simply because that 8x1.25 bolt on the back was overlooked. Also, the hole on both ends of the weld thing...

 

[99gst_racer]

Also you have to drill holes in each end of the crack or it will keep cracking. This something I was told in welding class

You definitely need to drill the ends of the crack or cracks before repairs as stated above. This is important because if you just groove and weld it the crack will eventually come back to haunt you. Drilling the hole helps put an "end" to the crack so it does not continue on its path. You can usually see this when grinding away material that has a crack in it. If you grind past where the crack looks like it ended, in more cases that not, you will see that it actually continues just past where it appeared to end. Same thing applies to stopping a crack in plastic (oh the good old days of motocross quick plastic repairs and "stitching stunt bike fairings back together).

Agreed. Always drill holes on an aluminum crack. I did the same thing to fix a cracked SMIM and I never had an issue with it after that.

 

[T is for TURBO]

Agreed. Always drill holes on ALL metal cracks. I did the same thing to fix a cracked SMIM and I never had an issue with it after that.

Fixed
I work in the mining industry (engineering), and when ever we have a structure that has a crack (which is often, due to the very high stresses our machines and structures are exposed to), wheather it is aluminum, structural steel, cast *insertmetalhere* we always instruct our field engineers to drill the ends of the crack to "stop them".

But as bastarddsm said, welding aluminum will soften it. So thats always going to be an issue

 

[turboglenn]

I have to vote again for the drilling, but one thing you can do (along with drilling) is try and use a different alloy if you cna getit to flow into the cast. Most times 4043 is sued on cast because it's properties help it flow well, BUT, if you use 5053 and can getit to flow it will hold up much better. Also keepo welding and grinding it smooth and rewelding untill you have full fresh metal in the place the crack was at, makes a world of difference because cast is dirty, porous and weak to begin with. 5053 is stronger in all ways until temps surpas 150*F which is close but not close enough to worrry about. When i do transmissions i use 4043 for the most part, do the drilling (and it's important to find the VERY END of the crack, and not just where it "apears" to be.) but i always weld, grind, weld, grind untilli've replaced most all the previouse cast aluminum with fresh melted weld rod in 4043 alloy

 

[Hesh724]

I am going to take the car to my buddies shop and we are going to use an alum. Spool gun on it. I will make sure to drill the end of the crack this time. I will probly be getting a diffrent trans this srpring. i want a shep but may not get enough for income tax return so i may be looking at a used one. I was really hopping to get advice on things i can do and look for so this new one doesnt crack.

Thank you!

 

[Aproductions]

I was really hopping to get advice on things i can do and look for so this new one doesnt crack.

You got all the info you need.

1. I bet if you welded the transmission better the first time it would not keep happening (drilling the end holes and doing the weld, grind, weld, grind method that Glenn mentioned).

2. make sure all the mounts match (BogusSVO)

3. double and triple check that all the bolts are torqued properly and that you have nice dowels.

 

[dylnwit]

also make sure there is nothing between the mating surfaces of the engine and the trans. Had this happen to me on my 1g. (reassembling in a poorly lit parking lot, water line clamp got between the trans and the engine, didn't take long to get a crack there)

 

[turboglenn]

I woldn't let them weld it with a spool gun/MIG, it isn't going to clean the metal like a TIG would and the weld will be weak. from a weldor's word of advice, have it TIG'ed and do it according to my instructions. Since my injuries and have to quit construction this is how i make my living, and i'm telling you if yo MIG it with a spool gun you'll be pulling it right bakc off in a week or two

 

[Lofty]

The one where the bolt goes through the one dowl pin in the back is missing cause there metal is broke off back there. sadly

This is your problem. Reweld the broke metal properly as there is a special way to weld cast. You are forever going to be plagued with trans issues. Sorry.

 

[turboglenn]

This is your problem. Reweld the broke metal properly as there is a special way to weld cast. You are forever going to be plagued with trans issues. Sorry.

shazam!!!!!! exactly, cast is one of the most difficult welds to make and have a good end result. YOu need some one who either welds to make their living or is/has been into it so long they know exactly what they're dealing with from the moment they look at it.


there's two methods for doing cast, and if they can do the weld in under 20 minutes they didnt do it right no matter what

 

[Lofty]

I had the same issue on BOTH my dsms. Traded my nt for a TSI AWD. new car had cracked ear on front. Got it welded up by a professional.

You have to heat the cast and weld it with a nickel rod to get it right. Id take pics of it for you if youre interested.

 

[Hesh724]

I had it welded right the first time i pulled the trans had V'ed it and had it tiged inside and out. and it after a few months it has restarted at the top. but not before i got a crack in a whole diffrent spot. I had the new crack miged cause i didnt have time to pull the trans and the welder said there wasnt enough space to get the tig stuff down inthere. he does it on the cheap so i have a hard time asking him to go to alot of trouble. but i guess the only answer may be to get a new bellhouseing and take it to a trans specialist and get it rebuilt and re syncroed? or just get a rebuilt one or something?

 

[Lofty]

Im not talking about your trans. I'm talking about you MISSING THE BOLT IN THE BACK OF YOUR BLOCK.


You need this there.

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Ask me how I know....

Edit:
Found more.

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You don't want this to keep happening, do you?

 

[turboglenn]

I had the same issue on BOTH my dsms. Traded my nt for a TSI AWD. new car had cracked ear on front. Got it welded up by a professional.

You have to heat the cast and weld it with a nickel rod to get it right. Id take pics of it for you if youre interested.

yea, you need to heat cast iron to about 400* F or so before welding, then hold it there for about 20 minutes after the weld and SLOWLY let it cool ( i like to use charcoal/wood in a grill, (oven is ok but stinks up house) I heat it with a torch but once i'm done i sit the part in the burnt out charcoals/wood pieces and let them burn out and cool with the part if it's small enough to fit in said grill

another way to do it (all methods using the 99% nickel rod) is to take and weld with the part cold, but weld NO more than 1/4 to 1/2 inch at a time and let it completely cool, then do another 1/4 inch or so and repeat.

the 1/4 inch and repeat MAY still make a "tinking" noise when cooling which is it cracking internally on the weld but this way DOES work, the trick is to weld so little at a time that the metal never gets up to it's optimum temp of 450* through out..

So that's why both ways take a LONG time, you either need to heat and keep it heated or do a bunch of short welds so it don't heat up and give it enough cool time between welds that it never builds up heat, and on method two i mean NO HEAT left, not warm, it must be back to like cooler than room temp

Also, 99% Ni rod is hard to find in TIG selection, so just buts the fluyx off ARC welding rod that's 99Ni and use that (it's what i do) and by the way, ARC welding is the preffered way to do method two because there's no heat build up while you're forming a "puddle" , and method one can be done that with ARC/Stick too, but TIG is muchbetter if you can... I ARC weld on method two but you couold substitute TIG if you had it and couldn't ARC worth a crap

I have welded a few ears back on 4g63 engines and so far all have held, i've also welded many many trans cases both DSM and other and all have held... the customers always say "it should only be 10-15 minutes right/" and i just laugh.. proper welding takes TIME, matter of fact when i get calls and they say "i've got a job it will only take you 5-10 minutes" i usually turn the job down, any weld done in 5-10 minutes on a non prepped surface will be crap,, you'll have 20-30 minutes in cleaning and surface prep to begin with, then welding time


ok i stop rambling now

Anyone needs cases and such welded and can't find some one local (especially tranny parts) just ship em to me i'll do em alon with other batches to save heating and other costs and hook you up just for being fellow DSM'ers

 

[pauleyman]

Why don't you just replace the bellhousing? Transmission parts are plentiful out there from guys that have fragged transmissions.

 

[turboglenn]

Well, if people have junk AWD tranny cases/parts to get rid of i'll take em i need to start working on a spare and with my new budget of being cap'n-cripple, i figure i'll be piecing it together like J. Cash did his cadillac (butusing the best parts i can get for internals) so let me know i'll pay shipping

But seriousely, a welded bell housing or case should hold just fine when done correctly