I purchased a new unit recently at a large swap meet and saved some money. It has never even had fluid in it. Now the rub....a rubber transmission mount was loosely attached when I got it and they used 3/8" coarse thread bolts. Luckily they weren't tightened much but they obviously altered the actual 10mm thread enough that I can't get the correct bolt started and the 3/8" bolt threads about 5/8" into thread before binding pretty good. So, looking for suggestions on what to do. I can't access the top portion of the thread to attempt to clean it up. If I could get a transmission mount (poly) that would attach to the outside threaded holes I'd be fine but.....don't know if there is such a thing. :(

I think most of the kits and the mount used with them utilize the outboard bolts. Mine were 7/16"-13.

Does your TKO have a tag on it, and have you verified it is for a GM application? The OE style GM replacement mounts use the two inside bolts, but mine were SAE thread; I am not sure what size, but I revied my photos and I see I used Grade 8 bolts, which aren't available in metric.

Mike Pell's info does say to use 10 mm 1.5 pitch bolts, but mine were SAE. His writeup was for a 3550, so maybe things had changed for the 600 by 2004.

The Ford mounts are supposed to use the wider spacing, but I don't know of a mount that is the right height. I looked up a 98 Mustang Cobra mount, but it appears to be a lot taller. http://info.rockauto.com/Anchor/Detail.html?2784.jpg

Call CMG?

I have a TKO 600 from Classic Chevy 5 Speed and it used metric bolts on the part that mounts to the transmission. I would call them, as they are very helpful, and ask if they have another mount that you can use or modify. If I remember right, there are four bolt holes, so all you would have to do is find a way to use the other set. The other option would be to ask if there would be an issue with drilling out the threads and just tapping it out one size larger with whatever you wanted to use.

I didn't like the use of metric, as it was confusing to me, but they supplied the bolts in my case as part of their package.

-Kevin

Find a "bottoming" tap of the correct size and pitch and correct the messed up threads.
See below.



Bottoming taps have no taper at all. As a result, bottoming taps cannot be used to start a new thread. Bottoming taps are used only to bring an existing thread down to the bottom of a "blind" hole (a hole that does not go all the way through the material).

Does your TKO have a tag on it, and have you verified it is for a GM application? The OE style GM replacement mounts use the two inside bolts, but mine were SAE thread; I am not sure what size, but I revied my photos and I see I used Grade 8 bolts, which aren't available in metric.

Mike Pell's info does say to use 10 mm 1.5 pitch bolts, but mine were SAE. His writeup was for a 3550, so maybe things had changed for the 600 by 2004.

The Ford mounts are supposed to use the wider spacing, but I don't know of a mount that is the right height. I looked up a 98 Mustang Cobra mount, but it appears to be a lot taller. http://info.rockauto.com/Anchor/Detail.html?2784.jpg

Call CMG?


I am with Eric, both of my TKO's (500 & 600) , had 3/8 x 16 threaded holes in this mount surface. I recall this very plainly as they are a little hard to start by hand, once the trans is installed in the car with the crossmember in place. I usually have to leave one side of the crossmember out of the way to get to these bolts.

But its not a big deal, if you need metric, use it. Its the transmission compatiability that is in my mind now for you. Some people mistakenly get these Ford transmissions thinking they will work. I have found , the input shaft needs to be changed , as Mike Pell told me once. Hope thats not your case.

To my knowledge the inboard bolts on a TKO have always been 10mmX1.5. The outboard bolts (Ford mount) are 7/16". Why 10mm??? I have asked Tremec and have failed to get a good reason. Depends on who you talk to? I'm with 1962vette with the bottoming tap. If you can find a short one you can come down from the top into good thread and turn the tap right through. Sometimes a thread chaser will do the job as well. Depends on how messed up the threads are.

Thanks for all the advice guys. I found a local Tremec dealer here and he also says 10 mm. The outer 7/16s would be great to use but all the trans mounts and only made width for the inner 2 holes. This dealer said.....get it to him and he'll just helicoil replace the threads and will be better then new. Obviously , too frequent of a a screw up. Darn men don't want to read directions.