Shift Kit

I've done shift kits on other transmissions. Not really that difficult, just take your time and follow the instructions. Also everything must be perfectly clean when you put it back together. While a shift kit can change how the transmission shifts it won't change the off the line performance. To help that you can either change the rear differential ratio (not really possible due to lack of different gears) or change the torque converter. Selecting the best torque converter requires you to provide things like the rear gear ratio, weight of the car, horsepower, torque of the engine, and what you want to achieve. There are many companies that make different torque converters and they can help you chose the correct one.

 

A shift kit won't do anything for "off the line" performance, only firm up the shifts.
The shift kits consist of a new plate for the valve body and gaskets.
By removing a check ball and enlarging a couple of holes in the plate you do it yourself for free. I've done it decades ago and it worked great but I couldn't remember exactly what I did even at gunpoint now.
Search online for the info it must be out there. You can also fool around with the vacuum modulator to delay shifts and raise shift points via the governor.
Better yet buy a book on hopping up the TH400. It's a bullet proof trans with lots of potential for modifications. None of which will make it's three ratios better suited to the torque curve of our lumps.

 

I've read somewhere that you can change the internals in these ameracan autos. So that you can get maybe four or five speeds. Has anyone tried that? It should improve the performance of the car.

 

Nope, three speeds only, carved in stone. You can add an external overdrive on models without the torque tube as on our cars.
There is at least one 400 or 412 with a 4 speed GM 4L80 (a distant relative of the TH400)automatic installed. Lots of work to do that.

A "loose" torque converter might improve "off the line" as the engine has a chance to get some revs up before being asked to move 2 1/4 tons. This is a drag type modification and some will find it annoying on a road car. Fuel economy, if you care, will suffer mightily as well.

 

If it held the 1st a tad longer that would help too. Shifts into 2nd too soon for the weight of the car. Losing the TH400 is the answer.

 

I'm curious if anyone has attempted to convert an auto transmission to a manual (5sp) transmission? To me, this would be the ultimate "shift kit".

Does anyone know what other cars may share the transmissions in our manual cars?

Cheers!

Ruben

 

This could probably be improved upon by manipulating/modifying (increasing) governor pressure, assuming such option is available in this type of transmission.
I'm not familiar with add-on/aftermarket "Shift Kits", but perhaps this objective is one of their purposes.
OTOH, I have rebuilt/restored number of "vintage" automatic transmissions, but most have been for cars from 1950s & 1960s and only few involving this type of engineering (due to no "Shift Kits" available).

 

Under full acceleration it shifts from 1st to 2nd at 100KPH. How high do you want it to go?

A modern 6 speed auto would be nice.

 

Because the micro switch is engaged overcoming governor pressure. Anything less than near full and governor pressure shifts it like it's a limo.

 

A 6 speed with 2 overdrives would make the car an even bigger slug. It already has a hard time pulling the skin off a rice pudding.

 

We know a bloke on here that will probably go down that road,after he gets the handling,overheating,electrics(anything I've missed,Pat?),sorted out!

 

Tyres, rust, steering, brakes

 

Put a dash switch to overcome the governor and shift it manually when you want it.

 

The governor is a centrifugal valve on the output shaft so no switch applies and manually shifting over-rides the governor anyway.

 

I know Paul, but you were talking about a microswitch at full throttle so I thought Ferrari had some king of switch added to it. Or are you talking about the modern 6 speed GM like my Vette slushbox. That stupid thing even in sport mode shift like an old rubber band.

I really don't get it, with todays technology and all those electronic modulation valves they could make it to have firm crisp shifts when you want it. What is the point to have steering wheel shift buttons on a sport car when it still shift like an old Cadillac.

 

There is a micro switch on the accelerator linkage that is activated under full throttle. When I first got my car this switch was not working & the car was a real slug, changing gears too soon & not kicking back as it should - fitting a new switch really changed the way the car drove. I also adjusted this switch so it comes in a bit before full throttle.

 

I bought a B&M shift kit to install but haven't gotten to it yet. However, I find it works fine moving the shifter 1 / 2 / 3 when I want to shift. I have a nice uphill twisty section that I hold second on and though it is not a manual, I enjoy the sound and feel!
Really would like a tranny like my BMW 840 that can shift into sport mode and modify shift points.