Vintage Thunderbird Club International

There's an interesting post here from a couple years ago about putting a C6 into a 62 (Graeme 'ozbird' et al.)

To follow up, I have a chance to get a C6 very reasonable, so was thinking about replacing the COM in my stock 62.

Is that a good idea?

If so, how big a job is it?

Will it require 'shift kits' or new mounts/braces?

Will my dual exhaust headers be in the way?

Just testing the waters (I am NOT a transmission guy, so all will be hired work).

From what I can remember you have to do some mods to the mount as the C6 mounting position sits further back. There should be other posts on the topic. I'm sure I've seen pictures of the mod.
viewtopic.php?f=23&t=6912&start=15

Not sure what the advantage would be in the end. They're both 3 speeds and the COM is a stout trans and functions super nice after a rebuild with updates.
Since it isn't a simple bolt-in mod it will be a lot of work and some fabrication for little in return.

JMHO,

Scott

RedBird64 wrote: ↑Sat Jul 13, 2019 6:12 pm Not sure what the advantage would be in the end. They're both 3 speeds and the COM is a stout trans and functions super nice after a rebuild with updates.
Since it isn't a simple bolt-in mod it will be a lot of work and some fabrication for little in return.

JMHO,

Scott

Thank you, Scott - then I won't worry about it (I thought the C6 was maybe a 4 speed?)

The difference is parts availability. With the c6 you can get all the performance goodies and any tranny shop to work on it. Not so with the COM. The shift kits that were once available for the COM are rare, and shops are shy about working on them. If you have a rebuilt COM and don't need any extra performance, then stick it in and enjoy. I have a performance built c6 and plan (?) To do the mods for a swap. It shouldn't take more than a weekend or 104.

stevegintn wrote: ↑Mon Jul 15, 2019 12:37 pm

RedBird64 wrote: ↑Sat Jul 13, 2019 6:12 pm Not sure what the advantage would be in the end. They're both 3 speeds and the COM is a stout trans and functions super nice after a rebuild with updates.
Since it isn't a simple bolt-in mod it will be a lot of work and some fabrication for little in return.

JMHO,

Scott

Thank you, Scott - then I won't worry about it (I thought the C6 was maybe a 4 speed?)

No, I wish they were 4 speeds!
FWIW, I just checked a couple of sources and shift kits are readily available from Transtar along with all the wear items.
Some of the more unusual parts, like drums, are harder to find but they aren't normal wear items and wont get replaced unless something very unusual has happened.

Even without a shift kit, the COM is a fine transmission and will work like it did off the show room floor with a simple rebuild kit (avail from several vendors).

A C6 can be built stronger so if you have a ton of HP and want it for all out performance purposes (or something like a manual valve body). For a strong DD, the COM is great.
A C6 that's heavily built (and thus, shifts harshly) would be my choice if an aftermarket OD was added.

S

OK, so what does that 'shift kit' do for you?

stevegintn wrote: ↑Sun Aug 04, 2019 10:03 am OK, so what does that 'shift kit' do for you?

It firms up the shifts a little to save on clutches/bands and gives it a slightly better shift "logic". IIRC, it increases pressures under certain circumstances.
The trans feels more "crisp" - if that makes sense. The difference is very subtle though.

RedBird64 wrote: ↑Fri Aug 16, 2019 2:00 pm
It firms up the shifts a little to save on clutches/bands and gives it a slightly better shift "logic". IIRC, it increases pressures under certain circumstances.
The trans feels more "crisp" - if that makes sense. The difference is very subtle though.

OK, thanks again, Scott - sounds like some thing to look into? Are the kits expensive?

stevegintn wrote: ↑Sat Aug 17, 2019 9:24 am

RedBird64 wrote: ↑Fri Aug 16, 2019 2:00 pm
It firms up the shifts a little to save on clutches/bands and gives it a slightly better shift "logic". IIRC, it increases pressures under certain circumstances.
The trans feels more "crisp" - if that makes sense. The difference is very subtle though.

OK, thanks again, Scott - sounds like some thing to look into? Are the kits expensive?

No, they're very inexpensive because there isn't much to them.

S

OK, great - is it something external (bolt on), or do you have to crack the case?

stevegintn wrote: ↑Tue Aug 20, 2019 11:19 am OK, great - is it something external (bolt on), or do you have to crack the case?

It replaces several parts in the valve body and may include drilling passages.
I will dive into most projects but I will never again try to install a shift kit (mans got to know his limitations...)
The one time I tried, it was nearly disasterous.

Scott