90 GT 5 speed trans with a cracked case
06-26-2012, 04:34 PM
#1
Team Owner
Thread Starter
90 GT 5 speed trans with a cracked case
I have a 90 GT 5 speed with a small crack just under the front drain plug.
I would guess its about 2 inches long,
the trans hit the ground in an accident,
there is a small amount of oil leaking from the crack.
Would this be something that could be welded.
Would it require total disassembly,
How much is it worth? ,
trans has 86K on it with a PSD
I would guess its about 2 inches long,
the trans hit the ground in an accident,
there is a small amount of oil leaking from the crack.
Would this be something that could be welded.
Would it require total disassembly,
How much is it worth? ,
trans has 86K on it with a PSD
06-26-2012, 05:02 PM
#2
Three Wheelin'
Mark A must have a pile of cases that he's broken gears in, I have a couple myself.
Welding could also be a proper repair if it's disassembled and clean. How bad does a hit have to be to do that? Broken fins fine but a 2 inch crack? Yikes.
Welding could also be a proper repair if it's disassembled and clean. How bad does a hit have to be to do that? Broken fins fine but a 2 inch crack? Yikes.
06-26-2012, 05:39 PM
#3
Archive Gatekeeper
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I don't know jack about aluminum welding (or many other things, for that matter, but it doesn't stop me from WAGging on the intternets) but aren't you sort of required to have the aluminum completely oil-free if you were to weld on it? Seems like dissassembly would be necessary to make sure you got a good weld. Wouldn't want the crack propagating to where it might compromise the casting around where the layshaft sits.
If you needed another case and want to preserve the PSD you'd be constrained to either a G28.55 or G28.57 case, though I recall Erkka showing pictures of G28/12 or -13 boxes with the boss for the PSD slave cast in place. Perhaps one could find one of those cases and have the boss drilled and tapped. It's a simple straight thru shot:
In terms of worth, as-is, if the case is toast I would guess $1500 for the gearsets and the PSD if all the guts are ok. A complete, intact G28.55 is $3K when they come up for sale. Greg charges $1200 plus parts to properly go through one- total bill on the rebuild of mine was $2400. So if you were lucky and all the gears, PSD and synchros were ok (unlikely), $1500 for the guts + $1200 labor + a new case would get to $3K pretty quick. And another $K more if you replaced synchros 1-3, the input shaft bearing, disassembled the PSD (God help you if those plates are done....) and any of the needle bearings.
If you needed another case and want to preserve the PSD you'd be constrained to either a G28.55 or G28.57 case, though I recall Erkka showing pictures of G28/12 or -13 boxes with the boss for the PSD slave cast in place. Perhaps one could find one of those cases and have the boss drilled and tapped. It's a simple straight thru shot:
In terms of worth, as-is, if the case is toast I would guess $1500 for the gearsets and the PSD if all the guts are ok. A complete, intact G28.55 is $3K when they come up for sale. Greg charges $1200 plus parts to properly go through one- total bill on the rebuild of mine was $2400. So if you were lucky and all the gears, PSD and synchros were ok (unlikely), $1500 for the guts + $1200 labor + a new case would get to $3K pretty quick. And another $K more if you replaced synchros 1-3, the input shaft bearing, disassembled the PSD (God help you if those plates are done....) and any of the needle bearings.
06-26-2012, 08:26 PM
#5
06-26-2012, 09:36 PM
#6
Nordschleife Master
Replace the case and have no issues.
Otherwise it will always be a welded trans that hit hard enough to crack the case, so it "may" have other issues later on.
Otherwise it will always be a welded trans that hit hard enough to crack the case, so it "may" have other issues later on.
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06-26-2012, 11:35 PM
#8
Rennlist Member
I don't know jack about aluminum welding (or many other things, for that matter, but it doesn't stop me from WAGging on the intternets) but aren't you sort of required to have the aluminum completely oil-free if you were to weld on it? Seems like dissassembly would be necessary to make sure you got a good weld. Wouldn't want the crack propagating to where it might compromise the casting around where the layshaft sits.
If you needed another case and want to preserve the PSD you'd be constrained to either a G28.55 or G28.57 case, though I recall Erkka showing pictures of G28/12 or -13 boxes with the boss for the PSD slave cast in place. Perhaps one could find one of those cases and have the boss drilled and tapped. It's a simple straight thru shot:
In terms of worth, as-is, if the case is toast I would guess $1500 for the gearsets and the PSD if all the guts are ok. A complete, intact G28.55 is $3K when they come up for sale. Greg charges $1200 plus parts to properly go through one- total bill on the rebuild of mine was $2400. So if you were lucky and all the gears, PSD and synchros were ok (unlikely), $1500 for the guts + $1200 labor + a new case would get to $3K pretty quick. And another $K more if you replaced synchros 1-3, the input shaft bearing, disassembled the PSD (God help you if those plates are done....) and any of the needle bearings.
If you needed another case and want to preserve the PSD you'd be constrained to either a G28.55 or G28.57 case, though I recall Erkka showing pictures of G28/12 or -13 boxes with the boss for the PSD slave cast in place. Perhaps one could find one of those cases and have the boss drilled and tapped. It's a simple straight thru shot:
In terms of worth, as-is, if the case is toast I would guess $1500 for the gearsets and the PSD if all the guts are ok. A complete, intact G28.55 is $3K when they come up for sale. Greg charges $1200 plus parts to properly go through one- total bill on the rebuild of mine was $2400. So if you were lucky and all the gears, PSD and synchros were ok (unlikely), $1500 for the guts + $1200 labor + a new case would get to $3K pretty quick. And another $K more if you replaced synchros 1-3, the input shaft bearing, disassembled the PSD (God help you if those plates are done....) and any of the needle bearings.
06-26-2012, 11:51 PM
#9
Archive Gatekeeper
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It's a Ducati something. It's Greg's. I'm not allowed to have a bike until I have stage IV cancer.
06-27-2012, 01:25 AM
#11
Three Wheelin'
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JB Weld is an option. I had an oil pan with JB Weld and it held up for 20 years.
When we welded VW cases they were stripped and clean. Never had a real problem. My sense of it the case would have to be disassembled to get a good weld. But then again if the gears are far away then you might take a chance on welding. The crack should be ground out to a V so the new weld has some metal to grip into for strength and integrity.
There are gas aluminum rods that can be used as well. They can be a bit tricky but when applied work well.
I do have a good 87 five speed case it anyone is interested.
When we welded VW cases they were stripped and clean. Never had a real problem. My sense of it the case would have to be disassembled to get a good weld. But then again if the gears are far away then you might take a chance on welding. The crack should be ground out to a V so the new weld has some metal to grip into for strength and integrity.
There are gas aluminum rods that can be used as well. They can be a bit tricky but when applied work well.
I do have a good 87 five speed case it anyone is interested.
06-27-2012, 08:40 AM
#12
Rennlist Member
Here's a thread from a few years back where welding and patching pros and cons were tossed around re John Leidels engine with broken off sections. It was successfully welded, even though lots said it couldn't be, and then coated to get a smooth sealing surface. A pro welder shouldn't have a problem getting a structurally and cosmetically good weld.
Link ... https://rennlist.com/forums/928-foru...ld-you-do.html
Link ... https://rennlist.com/forums/928-foru...ld-you-do.html
06-29-2012, 02:39 AM
#14
Racer
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Hey
Stan,
My dad does tig welding on irreplaceable 30's/40's bugatti engines. Depending upon the severity of the crack... you would definitely have to disassemble the case and completely cleanse it of oil in the area of repair. A v groove would have to be cut into it to ensure the integrity, and the difficulty with older aluminum castings is that they like to crack while being welded, so stop drilling and other methods are used to ensure the problem does not worsen.
I had him do the tig on my fenders for the 928, with no problems, I developed a crack in the center of my cast (AMR) Hurricane wheel barrel on my truck years ago, and he repaired it several times due to further fatique and flex in the aluminum, so sometimes you have good luck other times not. Depends on the quality of the aluminum porsche used, the depth and severity of the crack, where it's flex/fatique points are. You may just be better off in the long run to replace the case, or jb weld it...
Aluminum welding requires a different skill set, tools, and the price for repairs matches accordingly. $$ GL, let me know if you decide to get it repaired he may be able to help out.
My dad does tig welding on irreplaceable 30's/40's bugatti engines. Depending upon the severity of the crack... you would definitely have to disassemble the case and completely cleanse it of oil in the area of repair. A v groove would have to be cut into it to ensure the integrity, and the difficulty with older aluminum castings is that they like to crack while being welded, so stop drilling and other methods are used to ensure the problem does not worsen.
I had him do the tig on my fenders for the 928, with no problems, I developed a crack in the center of my cast (AMR) Hurricane wheel barrel on my truck years ago, and he repaired it several times due to further fatique and flex in the aluminum, so sometimes you have good luck other times not. Depends on the quality of the aluminum porsche used, the depth and severity of the crack, where it's flex/fatique points are. You may just be better off in the long run to replace the case, or jb weld it...
Aluminum welding requires a different skill set, tools, and the price for repairs matches accordingly. $$ GL, let me know if you decide to get it repaired he may be able to help out.
06-29-2012, 04:29 AM
#15
Three Wheelin'
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For what it is worth Northern Tools is selling a Combo welding unit in the $600 range. Mig - with or without a hand spool - Tig and stick welder. It incluses the guage for gas. Looked like a nice rig and was 220 as well. You could easily add a spot welder as well.