Overdrive Transmission Comparison
 

I have decided to purchase an overdrive tranny for my 79 TA 4 spd. I have searched and spent many hours researching past threads. I have learned a lot. But I haven't found a thread that compares the different choices.

Here are my choices:
T-56 Six Speed
TKO 600 Five Speed
Richmond 5 or 6 speed

I have read many post regarding the TKO and this seems to be the popular choice. Because this is a sizeable purchase, I would like to learn more about the advantages and disadvantages of these choices in regards to: strength, Fit and Finish, performance etc.

What are your thoughts and/or experience with an Overdrive Transmission?

Thanks, Dave

I chose the TKO 600 for a few reasons.
Price was a factor as well as strength.
The Richmond 5 and 6 speeds are only rated for 450 ft/lbs of torque.
The new Richmonds are rated for 600 ft/lbs but are about $1000 more
than the Tremec.
My Tremec shifts very well,is quiet and is working perfectly.
If you do a search you should find all the information you need for the install.
If you do go that route Ford Motorsport makes an aluminum driveshaft that is perfect
for your application.
Hope this helps

Gord

The Richmond 5 speed is not a OD trans.The Tremic shifts WAY better than the Richmonds IMO.Tom

Actually there is a Richmond 5 speed OD now. Came out recently. Summit carries it.

Cool,will check it out!Still wont shift as good as the Tremic.Tom

Dave,

I just completed this swap about one year ago. I chose the TKO600 Kit from
Keisler Engineering. I have a 1976 Trans Am which was a 4-speed, so your car
should be exactly like mine as far as the swap goes. With the Keisler kit which included
Tranny, Crossmember, Driveshaft, Speedo Cable along with add-ons such as the Clutch and Pressure Plate, Lakewood Steel Scattershield, and Hurst "Style" shifter, I was
able to install this without drilling one hole or cutting one piece of metal. This is a
direct bolt-on which can later be returned to original so that nobody will ever know!!!
Why did I do it? Because I needed a tranny that would not self-destruct behind
500-600 lb-ft of torque. Are there fringe benefits? YOU BET!!! This car with a 500HP
462 has pulled a best of 22.4 MPG with 3.23 rears and 24.8 MPG with 2.41 rears.
Best MPG I ever got with the factory stock 200HP 455 and 4-Speed was 12 MPG
with stock 3.23 rears. However the 12 MPG was daily driving whereas the 22 and 24 MPG figures were under controlled highway conditions. Bottom line...This is some of the
best money I ever spent on this car and I would do it again. And NO, I don't work
for Tremec or Keisler. Just trying to share my experience.

Hope this helps,
David

The TKO-600 shifts really nice and will most likey put one in my 68. I have it in my monte carlo ss.

Dave,

I should add that the installation did result in the rear of the engine being lower than the stock location. This meant I had to install wedges (I think 2 degrees) between
the leaf springs and the perches to bring the drivetrain geometry back to where it needs to be, and also if using a stock intake or Edelbrock Performer intake, the shaker will sit low in the hood (especially in the rear). I had a special wedge-shaped carb spacer built to correct this. I later switched to a Performer RPM and did not need the spacer. With this set up the scoop was at the correct height in the rear but just a little too high in the front as the front lip of the scoop eventually broke off. This is covered by the boot and is completely un-noticeable with hood up or down. No problems ever since.

David

I'm partial to the TKO600 as well. The shaker will work perfect with a Holley Street Dominator, 1/2" spacer and ProTouring F-body's air cleaner. WFO's would work as well. This is because the Holley intake tilts the carb toward the front a few degrees. The Tomahawk probably has the same thing.

I put a T56 in my car, and if I had to do it again I'd go with a 5 speed. 6th is just too tall to have a cruising speed that won't attract police attention, and since I've moved to a small town I rarely even use 4th. But I got such a great deal on it ($1800, with new clutch and shifter, used for only 1000 miles) that it doesn't bother me too much.

FritzCat - the T56 wasn't exactly a bolt-in deal either, was it?

I mean, I know the TKO isn't unless you buy one of the kits like Keislers, but at least such kits are available for the TKO.

You guys who've installed the TKO and had the engine sit lower in the rear - why not put shims under the tranny mount to raise the rear of the engine and restore drivetrain geometry? Will the trans hit the tunnel if you do that?

Dave,

I must be getting old...I keep remembering important details after I post. The setup with the angled carb spacer and the stock style and Perfomer style intakes was with
the factory stock air cleaner base. The setup with the Performer RPM was with the WFO air cleaner base. I did not use the rectangle element supplied with the WFO kit.
Instead, I was able to find a short Accell air cleaner of the round variety that was low enough to allow the scoop to be mounted to the WFO base. I am also using a functional
hood scoop as this is my only source of air with the WFO base (no snorkle). I did install
the solenoid actuated flapper but I am here to tell you, the solenoid is not needed.
When you romp on it, that flapper is coming open with or without that solenoid.
(ALL THE WAY!!!)

David

Will,

Raising the rear of the engine with shims is not an option unless you are willing to hack the tunnel. I was not willing, as I need to be able to return mine to original at some point. As it is the top of the tranny is almost touching the tunnel. Even so, it poses no problem even at wide open throttle. No rattling, no noise.

David

Thanks loggerhead - I figured that must be why they angled it down. Good to know, as I fully intend to run a TKO in my '73 one of these days, and I have no qualms about taking a hammer to the tunnel to make it fit.

Will, the T56 was pretty much a bolt-in. I did have to "clearance" the tunnel, move the crossmember back and shorten the driveshaft, but that's about it. Other than replacing the clutch disc, all stock clutch linkage parts work just fine. The hard part was the tunnel, but everything else was relatively easy. I definitely recommend a trans jack for a T56, they're big and heavy!

Thank You
 

Thanks for all the feedback. I have been leaning towards the TKO after reading past posts, but wanted to make sure before shelling out the cash. I think the only reason I was considering the T56 or Richmond, was to get a 6-speed instead of the 5-speed. I definitely like the sound of 600ft/lbs instead to the 450 from Richmond and T56.

Fritzcat..... I was concerned about how useful the 6th gear would be. You confirmed my thoughts on the T56.

Loggerhead.....your info is invaluable. It sounds like you have already blazed the trail for the F-bodies. All the posts I have read have been from the GTO gang. They are cutting their tunnels and they don't have to worry about a shaker hood. I definitely want to have a functional shaker. I got a big kick out of you not needing the solenoid. I would just about die if I could get upwards of 20 mpg in my TA.

I have really debated what intake to use. I bought a preformer rpm, but then I have thought to use an old torker I, and now considering a Dominator. I like the tomahawk, but have heard good and bad about it. I'll have to solve that one later.

I am glad to hear the TKO shifts good. This was certainly one of my concerns. My mind is just about made up. Are there any Ricmond guys out there that want to try and change my mind?

Thanks again for all the feedback. Dave

I have the TKO 600, its the only standard i would use on the street.

It shifts SMOOth, looks kool and that 5th gear you cant beat on the highway

it was strange at first, 90 MPH on the highway rumbling along a little over idle..LOL

;)