TH400 Leak question

[dmack91]

OK, so my TH400 has started leaking. I have searched the threads and am a bit confused.

It is leaking out of the speedo housing (outside 90 degree box/mount on the side of the trans). I have seen a pic of the large o-ring that goes on the round section that the speedo box goes into on the case (ring is around 1 3/4" round).

This doesn't appear to be where the leak is coming from. I am assuming there is an internal o-ring, but can't find a schematic that shows one for the 400. I have seen the pics of the "bullet" and o-ring for the TH350. Does the 400 have the same thing behind the speedo box or something different?

Just wanted to make sure what I am dealing with before I pull the speedo box part out of the side of the trans.

Thanks for the help.

[bollybib]

Check out Posts #14 and #15 in my Project thread and see if that is any help.

[dmack91]

Thanks for the link. Mine has an extra piece that screws into the trans plate and then the cable screws into it. Looking at your parts, it looks like I probably lost the gear seal.

Thanks again for the help.

[bollybib]

Originally Posted by dmack91

Thanks for the link. Mine has an extra piece that screws into the trans plate and then the cable screws into it. Looking at your parts, it looks like I probably lost the gear seal.

Thanks again for the help.

Must be a gear ratio adapter for the speedo. My cable goes direct but my transmission isn't original and I have 16" aftermarket wheels so I have no idea how accurate (or innaccurate) my speedo is right now.

Glad to help. It's a pretty easy fix for what looks at first to be a big problem.