Automatic/Tremec TKX Swap 67 GTO
 

After sitting a few years, I'm planning on pulling the engine and transmission out of my 67 GTO. The engine is getting a refresh and I'm replacing the 200r4 with a tremec TKX kit from modern driveline that will include the peddle kit, clutch kit, new yokes, etc. I know I'll probably need some driveshaft modifications along with mods necessary to install the hydraulic clutch. I plan on purchasing a repop 4 speed console to replace the automatic console in there now. Besides the console A274WSA from Ames Perf what else will I need to make this happen? What else do I need to prepare for with this job? I'm having a classic car repair/restoration shop do the work this time since I haven't had good luck with big jobs like this in the past.

How did you like the 200r4?

There is something going on with it that caused the engine thrust bearing failure. Instead of trying to figure out the issue I decided to change things up instead. While it lasted, I did enjoy the 200r4 and the overdrive.

Love my TKO-600 in my '67 GTO and know that I would have loved the new TKX even more. Just happened to have been a year early in making the plunge to a 5-speed.

The re-pop shifter porch makes life a lot easier than trying to fab things up from scratch. We ended up with two frame holes lining up with the re-positioned crossmember., and had to only drill one new hole per side through the frame. Used my original '67 trans crossmember without a problem. Over the years I went from original 4 speed, T400, 200-4R, and back to the original 4-speed before going to the 5-speed and used the same crossmember for all of them.

My trans and kit came from Silver Sport and they included everything needed. One of the reasons for the upgrade was not only for the overdrive but so I could stop babying the original Muncie trans and 10 bolt rear. Because of the expected abuse I went with a Dana 60 and 1350 U-joints on both ends of a new chromoly driveshaft. Depending on how hard you plan to drive yours, you can go with a stock aluminum bellhousing or upgrade to one of several scattershields offered. The trans doesn't come with the stick and a nice touch is to use a stock looking Hurst stick. I used my old Muncie stick and just drilled a second hole in the bottom and enlarged the hole that was in it so it bolted right up to the shifter stub.

Probably more, but will let others fill in the gaps.

I have a TKO-600 with the .82 O.D. It's a ton of fun driving a standard. I did install a hydraulic clutch last year which made driving it even more enjoyable. The hydraulic setup is very smooth. As was mentioned on bell housings. I went with a Moser 12 bolt rear end with 3.73 gearing, QuickTime bell housing. 1350 U joints. I'm currently running an ACT clutch with organic disc. I tried two McLeod dual disc clutch kits and could not get rid of the chatter on taking off or reverse. They both had really nice pedal feel. My ACT clutch has alot more clamping force and that's where the hydraulic clutch kit made it a better pedal feel. I've always used the organic clutch disc on the street. My car doesn't see any track time. The ceramic disc is often used for more aggressive driving and grabs alot quicker than organic.
First I've heard of the new TKX transmission coming out. What O.D have you decided to go with?

Thanks for the replies and information. The OD my unit will come with is .68 and my math says that should put me at about 2200 rpm at 75ish down the highway. Sounds about right. Is the repop shifter porch you mention part of the console kit I'm ordering from Ames or is that something else? Maybe you guys can advise me on the clutch as well. The one suggested is this:

Copied from the kit sheet -

MDL Clutch Set, GM Kevlar/Kevlar, 11" Low lever height Hydraulic release diaphragm pressure plate for HRB Kevlar/Kevlar 11" disk 1-1/8" x 26 Spline pilot bushings alignment tool, (1 year warranty!)All MDL clutches are assembled, measured, tested in house and matched to your HP and use

Last time my engine was on the dyno it made 532hp/579tq. I just run BFG 235/60/15 tires to make sure it doesn't break expensive things until I decide to upgrade the rear end and such. The MDL guy did suggest beefier U-joints though (1350)

I used Silver Sport also for my Tremec TKO 600. Great trans and nice people to work with.

I was too early to get the TKX too. I have the TKO600 and while I havent gotten to drive it yet I will say in my 64 it went right in. Now I have new body mounts but other than the shift porch I had to do no floor mods. I have a Moser 9 Inch out back with 1350 U Joints and an aluminum driveshaft

Just ordered a tkx for my 69 a couple weeks ago. Will replace the th400. Should see it sometime next month fromSST

This it? https://www.moderndriveline.com/shop...nic-26-spline/ Looks like a descent clutch. Ask them what the holding pressure is of the pressure plate.
One thing to mention with the .68 OD is that hopefully your engine is happy at 2200 rpm.

If converting from an automatic to manual, a hole is cut in the tunnel where the shifter will come up and the shifter porch is necessary to give some height and clearance for the shifter mechanism whether stock 4 speed or aftermarket 5 speed. It is attached to the tunnel by welding, sheet metal screws, or rivets and made of sheet metal. Ames Performance has it listed on page 284 of their GTO catalog.

I've had all sorts of clutches and have had some problems with chatter and smooth engagements the farther I've gotten away from stock organic. Worse was the dual disk which preferred to operate as an on and off switch followed by the ceramic where there was always a bit of chatter with partial engagement when backing up. I'm using an organic/Kevlar disk at the moment and it is working out pretty good. A standard organic/organic would be worth it just for dead smooth operation, but so far the half Kevlar is acceptable.

My cam is about half way between the Old Faithful and Road Paver and on the flat it can cruise along down to 1,800 on level road. I've got 3.73's, 28" tall tires, and the .68 overdrive and it's only around 50-55 that I need to drop down to 4th. Never a problem going up a grade over 60 MPH.

Fantastic info so far thank you. I put the shift porch on my parts list. Along with a R151 boot and R146D bolt kit. It says the boot retainer is not available would one be easily fabricated or is there another source? I'm also ordering the A274WSA repop m/t console. Will I need a new light/wiring harness/mounting plates or can I reuse this from my auto console? What else am I missing to make this a complete project?

Check out this comparison vid of the TKO to the new TKX in a 1969 GTO:


https://www.youtube.com/watch?v=BgmDeXS0IQs

what are you doing with the 200R

Great video thanks! Not sure what will happen with the 200r4 but I plan on having the shop look it over for any obvious issues that could have caused too much pressure.

You’ll spend a good bit of time at lower rpms, so make sure your part throttle operation is smooth.

Sounds like the converter ballooned. Same thing happened to me 25 yrs ago with my 200-4R when Art Carr sold me a converter allegedly with an "anti-balloon plate", but turns out he lied about that... I didn't know any better, as I had never seen that mod. Learned all about that plate from Kris at Continental, where I got converter #2 to replace the junk A-C unit.

When the converter ballooned, the resulting end play shattered the needle thrust bearing in the converter and filled the trans with bearing shrapnel. Was so pissed!

Not only 1350's. Solid 1350's. Nothing like a stick!

What is the anticipated cost with converting a TH400 car to the new TKX manual?

I got 2 quotes on going from automatic to manual. It includes TKX, clutch, linkage or hydraulic conversion, slip yokes, shifter and adapter, pedal kit, and just about everything except a new console.

Quotes were $5300-$5700 so it is not an inexpensive project. I believe the transmission itself is $2795.