4L60E Transmission Pan Broken

[Jsiff]

Hello,

Picked up a 99 2WD Tahoe recently, went to change transmission filter and gasket on pan. Everyone knows these are supposed to be snug, bout 120 inch pounds at MAX. well, 1 of the 16 bolts snapped in half. I then used an extractor bolt to remove the broken bolt, and while keeping it center, it made contact w/ corner of pan, and as you can see... chipped the pan. Now luckily this is only 1 bolt out of 16... i am thinking that I could maybe get away with a good gasket and 15 snug bolts? or I could attempt to tap the internal thread for the bolt, and see if it would snuggly bite even with that corner chipped out... Nonetheless not an ideal situation... I'm decently mechanically inclined, but if it comes down to having to pull a whole tranny or replace due to this one error, I will not be able to do that.

any advice or input is appreciated. Thank you.

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[kennythewelder]

If it was me, I think I would use some gasket maker silicone, and silicone the hell out of it, then put it back together, and let it sit, overnight before adding any fluid to the trans. That way, the silicone has time to set up, before it see any trans fluid. You could drill out the hole, then get an aluminum plug to fill that hole, but before you install that plug, drill and tap it to fit your bolt size. You still would have to JB Weld in in place to hold it, and that would need to sit overnight. The 5 min epoxy just isn't as strong as the orignal formula epoxy. 3ed choice would be to weld up the hole, and retap it to size, and although that is the best fix, I don't think I would do that with the trans in place.

 

[0xDEADBEEF]

JB Weld putty up in there, drill, tap. Or ... if this something you don't care about, putty and then just run the bolt in while it's soft.

If you check out Project Farm on you tube, he's done some testing of the putty stuff, including threading it and trying to pull the threads out. Even the worst of those took a lot more than 120 inch-lb to let go.

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[Jsiff]

If it was me, I think I would use some gasket maker silicone, and silicone the hell out of it, then put it back together, and let it sit, overnight before adding any fluid to the trans. That way, the silicone has time to set up, before it see any trans fluid. You could drill out the hole, then get an aluminum plug to fill that hole, but before you install that plug, drill and tap it to fit your bolt size. You still would have to JB Weld in in place to hold it, and that would need to sit overnight. The 5 min epoxy just isn't as strong as the orignal formula epoxy. 3ed choice would be to weld up the hole, and retap it to size, and although that is the best fix, I don't think I would do that with the trans in place.

Yeah it's a ****** situation but it's been a good truck I care a lot about. I want to do it as correct as possible, so that if I'm fortunate enough to need to change transmission filter again in 70-80k miles, it can still be done. Right now I am waiting on new AC Delco pan bolts to arrive to my residence. I also ordered a new 16 bolt pan w/ a drain plug from LMC. I've got other GMT400's to drive, so I'm not in a huge rush.. i moreso want it done in the most right way possible after a the crappy situation that occurred.

 

[Jsiff]

JB Weld putty up in there, drill, tap. Or ... if this something you don't care about, putty and then just run the bolt in while it's soft.

If you check out Project Farm on you tube, he's done some testing of the putty stuff, including threading it and trying to pull the threads out. Even the worst of those took a lot more than 120 inch-lb to let go.

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I would like to be able to fix it as correctly as possible... JB Weld putty sounds decent initially, but are there any chances (even slim chance) that it could ever eventually break off and get into the transmission or pan? getting in pan doesn't matter too much I guess.. i don't know. I am waiting on new AC Delco pan bolts to arrive, as well as a new pan from LMC w/ drain plug. I also have the new gasket, so I guess it'd be tough for JB weld putty to break off and somehow get between the gasket or in the pan... just want it fixed as correct as i can for the bad situation it is....

 

[kennythewelder]

Yeah it's a ****** situation but it's been a good truck I care a lot about. I want to do it as correct as possible, so that if I'm fortunate enough to need to change transmission filter again in 70-80k miles, it can still be done. Right now I am waiting on new AC Delco pan bolts to arrive to my residence. I also ordered a new 16 bolt pan w/ a drain plug from LMC. I've got other GMT400's to drive, so I'm not in a huge rush.. i moreso want it done in the most right way possible after a the crappy situation that occurred.

Any decent machine shop, can make you an aluminum plug, and tap it to fit you bolt size. Drill the broken bolt hole out, and install the plug as I mentioned above. My first though was a helicoid kit, but it looks like it's broken at an angle, maybe. Drill the hole out the 1/2 and have a 1/2 aluminum plug made.

 

[Jsiff]

Any decent machine shop, can make you an aluminum plug, and tap it to fit you bolt size. Drill the broken bolt hole out, and install the plug as I mentioned above. My first though was a helicoid kit, but it looks like it's broken at an angle, maybe. Drill the hole out the 1/2 and have a 1/2 aluminum plug made.

yeah - it's broken at a slight angle. I have a tap and die kit, so I was looking to clean the hole up a little bit and then create the internal threading. That's why I went ahead and ordered all new bolts for it, hoping the new AC Delco bolts specifically for this, M8X1.25 would at least be able to bite somewhat with new internal threading. As known, it's only gotta be snugged up, so I'm hoping it'll work.... Does that make any sense.. or would you still suggest having an 1/2 aluminum plug made, even though I've got the bolts coming. Thanks again, appreciate it.

 

[kennythewelder]

yeah - it's broken at a slight angle. I have a tap and die kit, so I was looking to clean the hole up a little bit and then create the internal threading. That's why I went ahead and ordered all new bolts for it, hoping the new AC Delco bolts specifically for this, M8X1.25 would at least be able to bite somewhat with new internal threading. As known, it's only gotta be snugged up, so I'm hoping it'll work.... Does that make any sense.. or would you still suggest having an 1/2 aluminum plug made, even though I've got the bolts coming. Thanks again, appreciate it.

Without trying your idea, there's no way to know if it'll work. Give it a shot, and see, but use the plug idea as a back up. Since you have a tap and die set, you could make your own plug. Just go buy the 1/2 aluminum rod. All you need is maybe 1, 1/2 inches long about.

 

[Jsiff]

Without trying your idea, there's no way to know if it'll work. Give it a shot, and see, but use the plug idea as a back up. Since you have a tap and die set, you could make your own plug. Just go buy the 1/2 aluminum rod. All you need is maybe 1, 1/2 inches long about.

I appreciate the advice/input, seriously, thank you. I've always been big on preventative maintenance and doing stuff by the manual, and I can honestly say I've never had anything like this occur before. 30 minute job turning into 3+ day job. thanks for hoping on and chatting.

 

[Schurkey]

chipped the pan.

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Broke the PAN, or broke the transmission CASE? I can't tell from the blurry photo.

You said you "chipped the pan" but you're acting like it's the case that's damaged.

If the pan is bad...you bought a new pan. Problem solved.

If the case is broken...things get more complex.