Guys, have a turbo 400 with a transgo 2 shift kit. My tranny guy said the hole that was drilled in the plate for the 1-2 shift was large and would result in a hard shift to 2nd.......at the time I thought how hard could it be? Well you get tired of it over time......so can I resize this hole.......any method to reduce this hole size, or do I need a new transgo plate? Thanks
Is the cushion spring in rear acculator.....this will help soften then shift if missing........did the leave or remove the wave plate on the intermediate clutch......with it missing it could always be firm
Put a looser converter in it if you are running a stock comverter. That will soften it up at low speeds.
Ben, I’ll comment on this when I pull valve body for my tranny guy to modify. No Lift, I have 3,000 stall converter, the converter doesn’t change the harsh shift happening inside the tranny. The tranny is shifting hard to 2nd even at 10 mph. It’s great at wot- barks into 2nd nicely. Just a bit harsh at low rpms/low load.
If you have a 3000 stall converter then a converter change won't help but as far as the shift feel goes try a stock converter. I can assure you the harsh shift will be even harsher because it transmitts much more energy to the car at a particular speed. Conversly if you have a loose converter and no shift kit the shift will get softer and feel worse.
Ben, I know what your referring to now. I will check when I pull the valve body out. I may wait till December as I still have some great fishing opportunities here in Vancouver that is using my spare time. I’ll get back to you once it’s out and what possible mods are required or performed by my tranny guy.
Yep that's the one......there is 2 spring in there...1 is retained on the shaft....its a small diameter.....the other is larger......sometime the inner piston is even removed
I would put a new plate in and size up in tiny increments. A hard shift like that is only fun for the first couple minutes, they say the best, most efficient trasnsmission is the one you dont notice at all.
There is a 1-2 accumulator in the valve body of a th400, you can adjust the part throttle shift by changing the springs and even the spring locations on that valve. It has a very noticeable affect, especially at part throttle. Transgo -2 shift kits usually come with an assortment of springs and instructions for this. Thanks Brent
You got it bud, it makes a big difference at part throttle but doesn't really affect full throttle. Thanks Brent
Ben - the accumulator had both springs. Brent, I took the valve body off today........all of which were a lot of fun playing with tranny fluid under the car I might add! My tranny guy is going to modify the 1-2 valve body......x my fingers that does it. With our wet cool winter now setting in, will be a while before any test driving. I have a few more projects....4 core rad, drive shaft safety loop, my line lock install. Thanks
I changed the springs on the 1-2 accumulator, chose one level above the softest recommendation. Much improved. Still firm mind you, no where near as harsh as before. I did find the modulator valve difficult to remove, so would assume it was sticky. Used some 400 grit, cleaned meticulously and modulator valve is moving in and out freely. I’d still like to raise the 1-2 shift point.....I’m 2 turns away from fully seating the small adjustment screw in the modulator, so that isn’t going to do it. Besides, my understanding turning this screw further in will add to the 1-2 shift harshness. I have the governor set to shift at 4900 1-2. With current engine, that’s perfect. can-the governor be set up to raise the speed at which the car shifts to second at part throttle operation? Currently shifting to 1-2 at approx 8 mph. 2-3 is great at 30 mph currently. any help much appreciated
You might be able to raise it a little, but 10 MPH is pretty normal for 1-2 shift, minimum throttle. I believe you might be able to alter it by lightening the big outer governor weights. Some governors have big weights with holes in them, maybe drill holes in yours. Start small.
Get a spare governor, try to find one with lighter/smaller weights than you currently have. Install it, see what the shift points are and then get one of these kits. https://www.summitracing.com/parts/tci-326500 Decide which govenor will be your victim, pick a set of weights and springs to install. It will take a while to get the shifts exactly where you want them. I suggest using a spare governor to modify, that way if you get things really messed up you have a known good example to go back with.
This one is cheaper, https://www.summitracing.com/parts/bmm-20248 If the full throttle shift points are to your liking, and you can't get the part throttle shift points where you want them with the modulator, I think you'll need to modify those big outer weights. I agree, get a spare governor to play with. https://www.ebay.com/itm/GM-TH400-G...845692?hash=item3f7b6f84bc:g:DswAAOSwSfRbNF3C
