727 oil pan bolts failure

[Randall Raines]

Hi guys

yesterday I wanted to change my oil pan gasket on my 727 torqueflite. I have disassembled the oil pan and replaced the gasket (cork gasket not rubber). In order to be a bit more safe; I added a bit of red silicon (high temp one) and when I wanted to assemble again 1 of the 14 bolts was spinning free with the ratchet key.
I can loosen and disassemble it; but when I try to tighten it's still spinning free like it is not going all its length.

I changed the bolt; was better then I took my tightening wrench and put 175 inch.lbs (20 Nm) but I could tight only 11 bolts, 3 are spinning free with my torque wrench.

I precise, by hand seems OK, bolts are all tights (except the one I said before), but with torque wrench I can clearly not reach the 20 Nm with 3 bolts... What do recommand ? I'm afraid pan will leak if I put oil inside due to these 3 bolts. Maybe I can add some blue Locktite to be sure on the 3 bolts spinning. Otherwise I though about a thread chaser to clean the thread; I have notices some metal parts on the bolt when I disassembled it.

 

[Moms68]

I’ll let the tranny experts weigh in on a fix, but it’s not ok and it will leak. Thread inserts or heli- coils come to mind but whatever you use will need to strong enough to be toured to spec.

 

[Big Bad Dad]

X2 on the heli coil inserts. If you saw aluminum on the bolt threads, the trans case holes are stripped. Probably overtightened in the past. The heli coil process is an easy fix.

 

[HALIFAXHOPS]

They are stripped. If you can I have put longer bolts in in a pinch and nuts and washers but it depends where it is some you cant do that and have to go with a insert say helicoil. Sucks but what can you do?

 

[Big Bad Dad]

https://www.stanleyengineeredfastening.com/brands/optia/heli-coil

 

[turbine68rt]

Hopefully you're still using all oem fasteners. If a po used aftermarket bolts it's possible some may not have been the correct thread type. Shouldn't need more than 150 in/lbs. If threads are damaged then heli-coils may need to be installed like Moms68 stated.

 

[Randall Raines]

Thank you guys, so you don't think trying with thread chaser worth it ? I will see for helicoil anyway and try both, if thread chaser isn't good

but do you think I have to do it on all 3 ? because as I said 2 seems OK by hand.

 

[Big Bad Dad]

Thread chaser is going to cut away more metal when "cleaning up" the threads. It is used when there is a burr or a slightly damaged thread. If the hole is stripped, there is nothing left to use a thread chaser on.

If you have to purchase a heli-coil kit, I recommend that you go ahead and do all the holes, as they have all probably been tightened the same in the past, and may be partially damaged as well.

 

[493 Mike]

A lot of equipment comes new with thread inserts to eliminate the aluminum galling problem.
Mike

 

[dvw]

Heli-coil 727 threads all the time. Never use sealer on the pan. Many leaks attributed to the pan come from sources above the pan. Valve body shaft seals, dipstick tube, rear bandanchor pin, cooler lines/fittings, neutral switch.
Doug

 

[Randall Raines]

thanks again for help, Just for my information, the helicoil I have to order must be 5/16 in correct ?

1 question more, I'm in Europe, I see 5/16 is Ø7.938mm, what if I take an helicoil Ø8mm (easier to find in my location) ?

 

[1 Wild R/T]

thanks again for help, Just for my information, the helicoil I have to order must be 5/16 in correct ?

1 question more, I'm in Europe, I see 5/16 is Ø7.938mm, what if I take an helicoil Ø8mm (easier to find in my location) ?

8mm is fine, obviously you'll need new bolts though....

 

[khryslerkid]

Once fixed, leave the torque wrench in your tool box. Just snug with a 1/4 ratchet and extension with one hand. Like doing a valve cover. Good luck!

 

[Randall Raines]

Thanks I keep you aware anyway, I have already found a M8 helicoil kit for 30 dollars.

 

[threewood]

Common. I have at least 2 helicoils on both my 727's. And I have a spare helicoil kit for the next one that strips.

Before I fixed the stripped holes I used a piece of solid copper wire in the hole and tightened the bolt down on it which gave it a tight fit.

 

[MoparLeo]

Not using the FSM specs is what causes these problems in the first case. No such thing as a "calibrated wrist" regardless of what some people think
I had to pay to fix many customer cars over the years because of techs who were " experienced" and didn't need to follow directions.

 

[Babyblue66]

Just use a cork gasket without silicone. That **** is only good for intake corners and leaky thermostat housings.

 

[Geetex]

Thanks I keep you aware anyway, I have already found a M8 helicoil kit for 30 dollars.

If you are going to use an M8 to repair the stripped holes then do yourself a favor and change them all to M8 so that all your bolts match, may save a problem in the future.

 

[493 Mike]

When I rebuild transmissions I like to put a dab of antisieze on the pan bolt threads as I have had many come apart with galled threads. Antisieze is your friend.
Mike

 

[Slap Stick]

Just use a cork gasket without silicone. That **** is only good for intake corners and leaky thermostat housings.

And 2.2/2.5 valve covers.