ST300 swap to TH200 4R

First of all, I'm a novice. Second: I'm from Europe and have limited access to US parts and professional tranny workshops.
I bought a '67 Buick Skaylark 2-door hardtop cope (300 cid V8). It has a tock ST300 tranny and it is slipping. Instead of trying to mend it I'd prefer to go for an ST200 4R with the overdive.
I want to buy a rebuilt ST200 4R from ebay but I must be sure I get everything with it. Is there any of you who has done this befre and can dvise me?
1. What do I need exactly apart of the tranny coming with a torque converter? New cross member? Slip yoke? TV cable? What else? (I need an exhausive list.)
2. The tranny comes with a locking torque converter. Does this mean that I need any electroics to controll the locking? If I'd like to avoid any electronics, then shoud I order it with a non-loking torque converter for an additial $130?
Yur help would be verymuch appreciated.

 

I did the same swap although in a '64 convertible and it is pretty straightforward. You will need to move the stock crossmember back about 6". You have a hardtop so I'll assume the frame isn't boxed. You can slide the crossmember rearward and drill new holes in the frame where needed. If you're buying a rebuilt tranny from a transmission shop they should be able to supply you with a kit that includes a converter, oil, new dipstick, TV cable, throttle bracket/geometry corrector for your brand of carburetor and a new transmission mount. These parts can all be obtained piecemeal if you are buying the transmission separately. You will need to rework the gear selector since you are going from 2 gears to 4 or you can install a floor shifter such as a B&M Quicksilver. The existing slip yoke will work (as will the existing drive shaft). The existing flex plate cover should work too but may require a bit of trimming. The lockup torque converter only requires a switched 12v signal, nothing fancy required there although most folks use a manual switch in between the 12v source and the tranny so you can disable the lockup feature when you don't want it to engage. Some guys rig it so the lock up disengages when the brake is applied. It's a matter of preference. BTW, it's 2004R not ST200 4R. The ST is short for Super Turbine which means the torque converter is a "switch pitch" having multiple stall speeds. They were only used on ST300's and ST400's. Be aware that it is critical the TV cable is properly installed and adjusted or you can burn up the transmission in minutes. You can ask this forum when you're ready or search the internet for instructions. I would highly recommend using a pressure gauge to monitor transmission line pressure when adjusting the TV cable. Good luck and keep us posted.

 

Check your axle ratio. You might find its a bit too tall to allow effective use of your overdrive. Bruce Roe

 

Ditto. You really should have a 3.23 or a 3.42 (preferred) rear end gear for it to work properly. My transmission came from Trans Depot in Hudson, Fl, they set it up for "internal lock-up" no voltage required (I don't know how this works). There are also pressure switches on the valve body that close in different gears so you can figure out which one closes for 4th gear and connect that one to the lock-up solenoid. As mentioned, you can feed the 12 volts through toggle switch on the dash so you can turn the lock-up off for towing or hilly terrain.

 

Your expert advice is very much appreciated. Thanks!
The ST200 was a typo. Apparently I meant a Turbo Hydromtic TH200-4R.
I'm contemplatig to buy a 200R4 stock conversion package from Dannys Trannys. They are advertising it for $1420 on ebay (item # 322087014537). I don't want to race my Buick just cruise around. I guess a stock remanufactured tranny will do, right? My 300 cid small block is not a huge power plant anyway. Or should I go for stage1 (item # 321879604743) for an extra $100?
The pacage is containing (apart of the remanufactured tranny) :
Torque converter and bolts, carb linkage (I can specify the type), TV cable, speedometer, mount, dust cover, dopstick & tube, throttle bracket, lock-up wiring kit, Hayden cooler with coolant. What else will I need?
Will I be able to reuse the current slip yoke?

What do you mean by checking the rear end ratio? How can I find out the rear end ratio for a '67 Skylark with 300 cid engine?

 

Hi there read this swap:

http://www.v8buick.com/showthread.php?176591-TH350-200R4-swap-summary&highlight=200r4

To find out your rear end gear ratio just drive the car at 65 MPH, tell us the RPM the engine revs at that speed, and measure the hight from the ground to the center of the rear axle and we can calculate your gear ratio. If you do not have a tach, get one it is nice to have.

What the guys are saying is true I have a Caddy with a 200R4 trans and a 2.41 rear gear and it barely needs the overdrive gear unless you are going over 120 MPH LOL!

My old car I sold had a 3.42 gear, 200R4 trans and it was great, both off the line acceleration and low RPM highway cruise. 3.73 is good too.

 

For a non posi axle, I just jack up one wheel and turn it around exactly twice. The number of
turns the drive shaft makes is the ratio.

Cars here have a 2.41:1 axle instead of overdrive. With a switch pitch trans performance
isn't bad. Bruce Roe

 

I found out that my stock rear end ratio is 2.78. This means that (with my 206/70R14 tyre - which is very much the same as the original stock tyre) I'd make 75 mph in 4th with 1800 rpm. Is this a healthy ratio, or do you think my rear-end ratio is a bit too high? (N.B. I'm a pleasure cruiser, not a drag racer.)

 

Correctamundo