question ,for the transmission gurus ,,how do i change a manual shift B&M equipped turbo 400 auto , back to auto ?valve body change ? or ??????
Usually a valve body change, but might be missing the governor and tubes, modulator valve, etc that you'll need to find and install. Sometimes there are some other internal changes also. if you can find the instructions for the manual VB that's in the transmission, you can reverse them. Otherwise, might need to get someone experienced with the transmissions to take it apart and put it all back together again.
Sell the manual valve body TH400 and buy a standard one. You will probably make some profit on the deal as well.
It depends... On exactly...how it was made manual ! The way my old T-400 was, by the governor. With a properly working governor, the trans. was automatic in its shifting. BUT...if the governor was welded in the weights in the open, position, the trans. was a manual shift ! So...I'd say, take a look at the governor, if the counter weights are welded, just find a proper working one. If it's not welded open, then yes, it's done in the valve body. Mike
Squirrel is right. Depending on who's manual valve body is in it, it can have many internal mods. Direct clutch mods such as removed inner piston seal, removed center support sealing ring, plugged port in case, removed governor circuit, pressure regulator mods etc. If possible, it's best to determine just who's manual valve body setup it has, then reverse engineer it. May be store bought or home made. If you are not real intimate with 400s, it may be best to have a pro do it. Bill
Mine is done with a Transgo kit, which came with a different steel plate, plus springs and balls to go in various places. I wont ever go back, unless I found a trans with a stock unaltered trans and could drop the valve body and swap them. I don't have the instructions after 12 yrs. and wouldn't guess at what to do. Have you called B&M and asked if they can offer instructions and parts to return it to stock operation?
I can't offer much help here but the mention of B&M and Trans-Go rings a dull bell for me! I built a Pro/Gas car in the late 70's, the Turbo 400 transmission work was sponsored by a local trans shop, I supplied the used trans and a new B&M full manual reverse pattern valve body kit and he went through it, went out into the street for a test and the very first 1-2 shift was a 1-neutral, came close to destroying the 355 small block. Trans guy said he didn't have much experience with the B&M kit but he used a lot of Trans-Go products, he brought one over and installed it in the driveway and it worked perfect. All I got.
Is it reverse manual or forward shifted manual? Are you sure it’s a B&M built trans or just a shift kit? If it’s forward shift it may be as easy as a valvebody modification or replacement and or governor. If it’s reverse pattern it’s probably missing the intermediate brake band as well as the governor, modulator and the valve body is heavily modified.
Hello, For all of the trouble the workers at B&M transmission shop went through for a harder shifting transmission, why would you want to take away the positive thing that it has going for it? An old B&M transmission is a catch in itself. We had plans to step up in the world of going faster in our 671 supercharged SBC motor in our 1940 Willys Coupe. We had choices and it was looking good for more speed parts for our build. Plus, the competition was turning to stick hydros to get an advantage over stick shift race cars. One of the final race parts to allow us to go faster and quicker was the modified B&M Stick Hydro transmission. We had purchased a C&O Stick Hydro for our 58 Impala after it was turned into our street driving sedan. It also served as a tow vehicle for the Willys Coupe. The C&O Stick Hydro made the Impala so much quicker off of the line and did its thing without me worrying about shifting a 3 or 4 speed transmission. Now, it was straight line driving with a lot more power to the ground. My brother was in talks with the B&M rep and they only sold the modified transmissions at the time. They did not do custom installs. So, the C&O folks did the whole changeover of our 58 Impala 3 speed stick shift to the Stick Hydro transmission, complete, out of the door. We were leaning toward that direction as they could get one in place within a week and it would be one of the last “go fast” items on our Willys Coupe list. Jnaki So, why would you want to make a custom B&M Stick Hydro transmission similar to the stock version? Why not go out and get a stock transmission or a similar set up and be done with it? The resale value of the real B&M would be helpful to someone else. But, I can see why you would want to do the change over. The racing Stick Hydro transmission is a hard shifting unit. The acceleration is there from your motor. But, the transmission left in drive just goes through the gears at full acceleration. No need to individually shift manually from 1-2-3 etc. Plus, most of those gears were available in the modified C&O transmission, but with the 4:11 or 4:56 Positraction rear end, the shift points were almost worthless and a hassle. They were very short and wound up the motor to shift almost instantly. It was tempting to hold the starting gear in first, but the motor at peak rpm sounded like a bomb was ready to explode. It was needless, but in “D” it took off with a minimal amount of worry. It shifted by itself and there was no need for a tach. Besides, who used a tach, concentration was on the straight driving in the lane and not what rpm. You could tell when it was going to shift from the motor. Plus, the next lane was empty as the Impala was usually out in front, then enough to show the 6 red taillights to the saddened opponent. Note: In 1991, my wife and I were ready for a new car. I wanted something for our small family and enough horsepower to enjoy some driving to the beach, vacations and up into the higher elevations of our local mountain ranges. So, we were looking at a Syclone Truck and a Typhoon station wagon. She had driven stick shift cars for over 20 years and now, wanted an automatic vehicle with some power. How about 280 hp and possibly 300 hp with an automatic? She was all for the automatic in the next vehicle. So, we went to a dealer to drive both of the truck and the station wagon on the city streets. We were going to trade in two of our stick shift cars plus cash to seal the deal. We were going to buy a mid size 4 door sporty sedan and the GMC truck or station wagon. We took it for a test drive and the instant power was amazing. The handling was perfect as it tracked and drove like a small sporty car around corners and slight graded curves. It was a sale we could not pass up. But, my wife said one small thing… "Why does the transmission shift so hard between the time we take off and the next gear?" She was right. My neck braced for the hard shift every time, but I was in a different mode and liked the feeling of power. It was similar to the full acceleration of my 58 Impala with the C&O Stick Hydro. Although it was much faster and all around better vehicle with the technology and tires. She said she would buy either one for me, but that she would drive the 4 door sporty sedan although it was a 5 speed. So, what did we do? Our neighborhood automotive tech wizard did some modifications to his Typhoon after he got the same message from his wife, too. It shifted so hard that it was actually uncomfortable. But, his knowledge of all things automotive made the Typhoon a fast smooth riding vehicle. No, we did not buy the mid size sedan and the Typhoon as the dealer did not want to make the sale. YRMV
I have a 400 with a Turbo Action reversed pattern manual vb with a brake in my Studebaker. It would be easier to build a fresh unit than try to undo the changes to this one. It has no 1st or 2nd gear braking. Also goes in reverse easy. But this is with a 4k stall convertor which would affect that. The biggest thing with a manual vb is a shifter that works well. I have a old Postal Jeep shifter in this truck and it is perfect for it.
mine has a b&m shifter with reversed shift and a lock out lever for reverse and park , i have bad arthritis in my shift arm , so ,,,and rear end gears are 473,sway too low for the street or highway but i do have a new set of 373s will this help not wind it out so fast im hoping so
Something to keep in mind is if your car has a very loose convertor going to a higher gear like the 373 will cause it to slip more. My truck has a 410 and that is border line to high for the stall I have with a 27 in tire. In my truck a 488 or a 513 would be better , but it sees limited use.
A gear change would definitely help hiway rpm and of course when you swap your reverse manual setup back to forward automatic you'll also need a new shifter.
That means you have to rev the engine until a certain rpm before the converter engages. So say it's got a 4,000 loose converter and you're below that rpm the engine rpms will float up and down trying to hit the 4,000 to engage the converter, kinda like a clutch slipping.
A stock convertor is 11 or 12 in. with lets say 2k rpm stall speed. You can have those loosened up a little to maybe 3k rpm stall. When you need even a looser convertor you get a 10 or even a 9 in . So looser equals more stall which lets you run a more radical motor.
ok gotcha its not that radical just a 327 w 350 heads with a mild cam that sounds great !im pretty sure its 11 or 12 converter
"Rated converter stall speeds vary due to engine size, engine torque output characteristics, vehicle weight, camshaft, and other factors. A large cubic-inch engine will raise a given converter's stall speed. Engines that produce more low-end torque cause a given converter to stall at a higher rpm. A heavy car with large diameter tires will raise effective stall speed as installed in the vehicle. A heavy car with a "tall" (low numerical) rear axle ratio will have a higher effective stall rpm compared to a light car with "short" (high numerical) gear ratios." https://www.motortrend.com/how-to/how-much-torque-converter-stall-speed/
The stall speed doesn't mean the car wont move forward at a lower speed than the converter's stall speed. It simply means the trans isn't fully locked up until it gets to a certain rpm. I have a 2800 rpm stall converter in my full manual TH350 in my Austin gasser, and when staging with my line lock set I can begin to feel it pull well below 2800. And driving on the street it takes off easily without my foot on the brake, or the line lock engaged.
If you have reverse shift pattern what happens if you have engine trouble and would like to abort a run? How do you pop it in neutral?
Almost any ratchet shifter (forward or reverse pattern) will require the driver to ratchet shift from whatever gear it's in to neutral if he needs to get to neutral. I don't think anything changes with a reverse pattern, except if you're in high gear it's going to take more clicks to get back to neutral. But it's going to take more clicks with a standard pattern if you have problems and you're in 1st gear also. My shifter doesn't lockout neutral, so it's just one more click from final gear to neutral. I like putting mine into neutral after I go through the traps vs. just letting is slow down in gear.
Agree. If the governor is welded in the open position, or has a spring clip holding the weights out, remove the clip or just replace the governor. Does it have a modulator on it ? If not , put one on it and hook it to manifold vacuum. If you're not familiar with the inner workings, it's worth a try..You don't have much to lose. You might get lucky ...You'll need those parts anyway.
You're kinda screwed, just let off the gas and ride it till it stops, that's one thing I don't like about mine, you can't just throw it in neutral and rev the engine at your buddy while doing a drive by. Not all manual valve bodies are the same either, some you can down shift while others you can't, you go back to first when you're completely stopped or almost stopped. I'm switching to a Kilduff shifter and it has a neutral lever but I'm not exactly sure if it bypasses 2nd and first or goes through them like a down shift.
It is not a good idea to put a automatic in neutral while at speed, the direct drum can over speed and explode .
I've read the same thing, but done this with my TH350 at the end of a pass for many years, and no issue here.
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