stripped transmission TH400 bell housing pan-mount thread

[Randall K.]

Bubba got me... Went to look for the source of a nagging transmission leak in my TH400, and found that one of the front bell housing pan bolt threads was stripped (one of two directly underneath the torque converter). The screw that was in place - and not doing any good at all - was some oversized sheet metal screw.

So, to repair - helicoil? Something else?

Thanks in advance for advice.

Randy

[Mike M.]

Re: stripped transmission TH400 bell housing pan-mount thread

helical the answer.apply good sealant to hell-coil and the bolt that it accepts. mike

[Steven B.]

Re: stripped transmission TH400 bell housing pan-mount thread

'Agree with Mike. I helped a friend repair one a couple of years ago and he used the helicoil. He drives his '73 8-10 months a year and has had no problems. Steve

[Greg L.]

Re: stripped transmission TH400 bell housing pan-mount thread

I agree that a helical is the traditional and probably the best repair for your situation. However Loctite and Permatex both make thread repair kits for your situation as well.

I've only used the Permatex kit once but it was back in the 90's and it worked great. I had one of the two bolts that hold the fuel pump to the aluminum housing on my GTO strip out and the local parts place suggested this method to get me going. I thought for sure the repair would fail because of the high temps, hot engine oil on the backside and the constant "working" of the fasteners to keep the pump in place during operation but it lasted for 6+ years and then I sold it.

Maybe I got lucky but given the same situation I'd use it again.

[Joe L.]

Re: stripped transmission TH400 bell housing pan-mount thread

Bubba got me... Went to look for the source of a nagging transmission leak in my TH400, and found that one of the front bell housing pan bolt threads was stripped (one of two directly underneath the torque converter). The screw that was in place - and not doing any good at all - was some oversized sheet metal screw.

So, to repair - helicoil? Something else?

Thanks in advance for advice.

Randy

Randy------


A Helicoil is the best answer. Installing one is not too difficult. However, the difficult part is drilling and tapping STRAIGHT for the Helicoil installation. When you have a part that you can get into a drill press, it's easy. On the car, not so easy.

[Randall K.]

Re: stripped transmission TH400 bell housing pan-mount thread

Thanks to all who replied. Helicoil went in succesfully last night, and holds torque!

Made a wood block drill guide to help make the expanded hole as vertical as possible, which seemed to work. Once the drill bit into the steel, it pulled the drlil, bit and block against the flat surface of the bell housing and kept the drill vertical.