Transmission to engine bolt size?

[cliffyp]

I'm missing one bolt connecting my transmission to engine that I would like to replace. The parts manual list it as part # MS90728-63, I tried putting that in on Naps's web site but nothing came up. I could remove one of the others and size it, but I figured it might be easier if someone happened to already know the correct bolt size. Thanks!

 

[wayne pick]

3/8-16X1.5in national coarse thread. The spec on these bolts is grade 5, I used grade 8 and blue thread locker when I had my trans rebuilt. Your choice.

 

[scottladdy]

I'm missing one bolt connecting my transmission to engine that I would like to replace. The parts manual list it as part # MS90728-63, I tried putting that in on Naps's web site but nothing came up. I could remove one of the others and size it, but I figured it might be easier if someone happened to already know the correct bolt size. Thanks!

Correct, page #170 of the -34P lists the part number as MS90728-63. Six are required. I often will use a site like WBParts - Aircraft parts, military parts, NSN, National Stock Numbers, avionics, connectors, Aircraft parts and components to look up part details.

Enter the part number, and you will get a page like this: 5305-00-688-2111, MS90728-63, B1821AH038C138N, B1821BH038C138N, 0014767 Screw,Cap,Hexagon Head showing it is specified as a grade 8 3/8-16 X 1 3/8 bolt.

I found that one of my trucks had 2, yes 2 , grade 5 bolts holding the transmission to the engine when I got it, and all seemed fine. I replaced those with six grade 8 parts, torqued to the correct value. Just goes to show you how strong the TH400 housings are.

I hope this helps.

 

[cliffyp]

Great, thanks guys!