Tried this post in the "boat load" section but only one response. Plan on installing a Transgo 1-2 Shift kit in my 1968 Wildcat. Any one out there already done this in a "big" Buick car and what size did you drill out the 2nd feed hole and 3rd feed hole? My car has a stock converter, stock turbo 400,non-posi 3.08 gears. I'be been searching all over this forum and others and have been getting all kind of suggestions but I have yet to find real world info on another buick "big"car.I would think that the weight of the car would affect shifting as well.
I'm not sure about the Transgo shift kits, but in the 4 or 5 shift kits that I've installed over the years, I always followed the instructions for the firmest shifts and was never disappointed. I like my cars, even the luxury ones, to shift very firm.
Thanks for your replies. When I had to rebuild my quadrajet earlier this year there was tons of info of tried and tested mods.Now..this turbo 400..which has been around least 50 years has not been as easy when trying to get specs for the drilling of the holes to affect the shifts.I thought that someone would of had it down to a science but only the Tranny specialists know and are somewhat vague in offering there advice.I tried talking to some local tranny shops but none of them answer my questions convincingly to make a decision .
I'd like to get it good on the first try. Dont have time to drain-drop the pan-drill..repeat etc..I'm looking for "driveability" with firm but not tire chirping shifts when cruising around but I want to feel it and chirp tires when I get on the pedal hard (wot).I was thinking of drilling the 2nd hole to .125,the 3rd to .140 and leave the accumulator feed hole alone.
Does your kit tell you to remove the accumulator spring in piston in the vb?? This alone will firm up 2nd gear. Does it tell you on the rear servo to remove the large inner most spring??? I'm not up on the directions in that kit, I just make my own when I do one.
That's the problem!! People tell me to drill the holes but do not elaborate on the exact bit size and it's affect on shifts. Also yes the instructions do mention removing and adding different color springs but the are vague on their effects and just offer a range from soft to hard shifts. .and three levels between. I want to not have to drain and drop the pan test drive...repeat. It is time consuming , especially when I have three kids running around!
I understand I have 2 myself. Springs inside accumulator like the one in the vb just cushion the shift like a giant shock absorber. But cushioning also slows it down. The reason why there is no exact answer is everyone taste on firm is slightly different and everyone's car reacts slightly different. Every kit is different If your worried about the biggest hole being too much and the next size down being to little big a size in between and have the best if both
There is an instruction kit, right? It gives you the size hole from soft, medium, to firm. If you go with anything but firm, you will be disappointed...unless you don't want firm. I was disappointed because I didn't go with the "firm" hole, and got a shift that was not hard enough.
I installed A 350-1&2 reprogramming kit in my skylark last summer, transgo had A YouTube video that was very helpful. I probably watched it half dozen times before I installed mine.They probably have A video on the TH 400,might be worth looking at.
First, if there is anything at all wrong with the trans, I wouldn't touch it with a ten foot pole until it is corrected. Putting a shift kit in it will only serve to make it worse faster. As a poor college kid I did one or two most weekends for spending money. I have done dozens of shift kits, 350 & 400, with a few being in bigger cars and many trucks. I did a truck for a friend a few months ago. I have never installed one at anything less than firmest option available. As others have stated, the RV and towing options tighten up the trans but it won't satisfy you if you want to bark the tires when you shift at the WOT.
With a full size converter still in your car, I would recommend .110 on both the A and B holes, and don't touch the accumulator springs. You can do the back to first at any speed if you wish..that's the new valve and plug. No need to change the pump relief spring. Then road test it... If you want a firmer 1-2, then just drop the pan, and pull the pin out of the 1-2 accumulator, and change the spring combinations. Don't even have to remove the valve body on that. Sounds like Adam needs to do this. I generally set that valve train up with no springs, for a hot rod with a smaller diameter converter. Get familiar with the 1-2 accumulator valve while you have the valve body out, so it won't be such a unknown if you want to change it. Now, if your 2-3 is still sloppy, then you can remove the spring in the 2-3 accumulator in the valve body. Clutch clearance and the possibility of hydraulic leaks past worn rings and seals are the X factors here, and why each trans has to be treated somewhat as an individual, when your dealing with putting a kit in, without a full rebuild. Read the instructions carefully, cover to cover. JW
All good advice! Thanks gentlemen. I don't have any tranny problems that I know of. My car has 71,000 original miles and the previous owner babied it and stored it winters. I just want to get some performance out of this turbo 400 with a firmer 1-2 Shift and want to feel the 2-3 shift that currently is hardly felt .
