Well crap! Stripped 42RLE pan bolts

minimull

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So a couple weeks ago I swapped the pans, changed the fluid and added a gauge to the 42rle on my son’s LJ, no biggie, everything went pretty smoothly. Today I tried to do the same my TJ. Everything was going well, sucked out what I could with the mityvac, dropped the pan, changed the filter. I got the lube locker and pan back up, started and finger tightened the bolts then I went to torque them down and proceeded to strip 8 out of the thirteen bolts 🤦🏻‍♀️. Seriously, I thought I did everything right. 😕 After a search it seems fairly common to strip one or two or and I even read about one guy stripping 5, but 8? I guess it’s off to O’Rielly’s in the am for a heli-coil kit. I’ve never used one before. Anyone have any tips or tricks or is it pretty easy? Also, can anyone confirm that they’re M8 1.25 pitch 15mm so I can get the right heli-coil?

B74BBD72-0AF1-4DC1-8C84-B09A0996712E.jpeg
 
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How tight are you torquing them? I‘ve had my ‘06’s pan off a few times over the last 3-4 years and torqued the pan bolts to 14.5 ft/lbs.

The parts list for my ’06 says M8x1.25x16
 
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Yes, the torque specs on those bolts are 14.5 ft/lbs. Not to be too critical of those who’ve experienced this, but it’s a user issue. I’ve replaced the filter in my transmission 6 times without issue. Using a lube locker likely contributes. A good bead of RTV is very forgiving if the bolts are under-torqued.

First time using a heli-coil, practice a few times before moving onto the transmission case. The bolt needs to go in smoothly. If you don’t drill deep enough, the heli-coil will taper and the bolt won’t go in deep enough to set.
 
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How tight are you torquing them? I‘ve had my ‘06’s pan off a few times over the last 3-4 years and torqued the pan bolts to 14.5 ft/lbs.

The parts list for my ’06 says M8x1.25x16
14.5. I know, I was shocked. If I hadn’t just done the exact same thing successfully on my 06, I’d think I was doing something horribly wrong, but I followed the exact same procedure. Still if anyone has any ideas of something I could have done differently to avoid this please let me know.
 
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Yes, the torque specs on those bolts are 14.5 ft/lbs. Not to be too critical of those who’ve experienced this, but it’s a user issue. I’ve replaced the filter in my transmission 6 times without issue. Using a lube locker likely contributes. A good bead of RTV is very forgiving if the bolts are under-torqued.

First time using a heli-coil, practice a few times before moving onto the transmission case. The bolt needs to go in smoothly. If you don’t drill deep enough, the heli-coil will taper and the bolt won’t go in deep enough to set.
I used the torque wrench almost immediately after hand tightening and never even got to apply force because there was never any resistance. I’m confused are you saying using rtv and leaving them under torqued is better? I’m definitely not above user error, but I don’t think I applied more than 14.5 ft lbs 🤷🏻‍♀️ Could there have been something else I did wrong? Also, if it matters I’m pretty sure this is the first service on this transmission as it only has 76k and had only been driven light duty on the road.
 
It's not uncommon, I've seen it on countless customer cars. 8x1.25 heli-coil kit is correct and you're good to go
Thanks for letting me know it’s not uncommon. I was feeling pretty defeated last night.
 
I used the torque wrench almost immediately after hand tightening and never even got to apply force because there was never any resistance. I’m confused are you saying using rtv and leaving them under torqued is better? I’m definitely not above user error, but I don’t think I applied more than 14.5 ft lbs 🤷🏻‍♀️ Could there have been something else I did wrong? Also, if it matters I’m pretty sure this is the first service on this transmission as it only has 76k and had only been driven light duty on the road.
Aluminum strips out incredibly easily.
 
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Thanks for letting me know it’s not uncommon. I was feeling pretty defeated last night.
Definitely a common problem. Another place to watch out for is the front four oil pan bolts that go into the aluminum timing gear/chain cover. It's very easy to strip those!
 
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Definitely a common problem. Another place to watch out for is the front four oil pan bolts that go into the aluminum timing gear/chain cover. It's very easy to strip those!
Good to know! I need to replace my rear main soon, so thanks for the heads up.
 
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The transmission is cast aluminum, and it’s grain structure isn’t super strong.

Personally, I wouldn’t try torquing those bolts and actually, I’ve never torqued a trans pan bolt.

If you use a lubelocker gasket and have any seeping, snug it down a little more.

If you’re using a gasket and RTV, or RTV by itself, snug it down and that should be fine.

Personally, I don’t use RTV on a trans pan, I don’t want chunks of RTV floating around in there, possibly clogging a valve body port. But that’s just me.

On the heli-coils, take your time. Keep the drill, and the tap as square to the bolt face as you can. Go deep enough, but not so deep that you break through in an inappropriate place.

And I understand there’s a bolt hole that does go through into the body and needs to be sealed when servicing the transmission. If you heli-coil that hole, make sure you don’t get any aluminum chips inside the transmission.

Packing the flutes of the tap with grease will hold the chips while tapping, preventing them from getting loose. Tap a turn or two, clean the tap, repack, then repeat until you’ve got the hole completely tapped.

Good luck with your transmission!
 
I used the torque wrench almost immediately after hand tightening and never even got to apply force because there was never any resistance. I’m confused are you saying using rtv and leaving them under torqued is better? I’m definitely not above user error, but I don’t think I applied more than 14.5 ft lbs 🤷🏻‍♀️ Could there have been something else I did wrong? Also, if it matters I’m pretty sure this is the first service on this transmission as it only has 76k and had only been driven light duty on the road.
Each time that I’ve dropped the pan, I’ve used RTV to seal it. When installing the bolts, tighten until there is resistance and go maybe another 1/4 turn - snug is just fine. The RTV ends up in the bolt threads so they won’t back out and the RTV seals the gaps. I’ve never experienced a transmission pan leak and I’ve use transmission specific RTV, black RTV, and The Right Stuff RTV .
 
Thanks for letting me know it’s not uncommon. I was feeling pretty defeated last night.
It's especially common on chrysler transmissions(42rle,46re,604,45rfe,to name a few main offenders). Undoubtedly, I have fixed many for a "over enthusiastic" apprentice, but as @Modoc Guy has already pointed out, the cast aluminum grain structure and porosity anomaly's means some of these are just the luck of the draw. You could have done everything right, and still pulled threads. you have nothing to feel bad about, and don't let anyone tell you different!
 
I just did this job without torquing down the bolts because I didn't like the way the 3/8ths torque wrench felt on such small bolts. I just got them snug with a quarter inch. As for the bolts unfortunately I had to reuse mine. The hardware I got was m8/1.25/16mm, but they were ever so slightly longer. Even though the top of the threads goes out into the open/exposed to the elements, it won't let you thread past the stock bolt length.
 
What size torque wrench did you use Minimul? They require so little torque I used a 1/4" so it'd be mid-scale for adequate accuracy and repeatability.
 
3/8s, Jerry, but I'll go with 1/4 next time it's that low, thanks for the tip. The weekend was too busy, so I finally installed the heli-coils today. Man, that was nerve racking, but it really wasn't all that difficult. I only torqued the bolts down until I couldn't move the washer, around 11ft-lbs. On the eighth bolt, which is the bolt that requires rtv, I just put a little extra auto trans rtv and left it alone. I'm hoping that keeps it from leaking. I was too scared I'd get shavings inside the transmission to drill or tap it.