Flight-O-Matic 1st Gear Start

[black56hawk]

quote:Originally posted by Lark Hunter

I'll have to side with Buddymander on this one. This is not hard to grasp, but somewhat difficult to explain, so I will use a rather poor analogy in an attempt to clarify. Which will be felt more: Dumping the clutch in first gear, or dumping the clutch in fourth? Which will throw you back in your seat harder: Slam shifting a car with 5.88 gears, or one with 2.73 gears? The torque multiplication of a lower set of gears will always apply a greater kick to the butt dyno. On an automatic, most of feeling of a gear shift under acceleration is absorbed by the fluid coupling, and further, the differences between, say, a 3.08 and 3.54, are more subtle than the extremes used in my example. LH


Straight from the horse's mouth

On my 4-speed car, dumping the clutch in low gear will spin the tires and thus transmit less shock load to the drivetrain; dumping the clutch in fourth won't spin the tires and the shock load to the drivetrain is much greater.

But this is really apples and oranges. The problem with just changing the valve body in a second-gear start Studebaker automatic trans is not any harshness in the shift from park to drive, nor in taking off from a stop, nor in the low to second to high shift sequence; it's the rough band-applied downshift to low gear when you are slowing to a stop from cruising speed. That downshift will occur at a lower speed with 3.73 gears than with 3.07 gears. Conversely, the downshift will occur at a higher speed with 3.07 gears than with 3.73 gears.

So - which downshift will be rougher? Shouldn't be too hard to figure out, I wouldn't think.

[buddymander]

Wanna buy a weather rock? Ya just set it outside your window and wait. If it turns white, it's snowing. IF it's wet, it's raining. Um, that is, unless you have a better explanation. Cuz maybe I just don't understand exactly how a weather rock works.

[mbstude]

George is a good mechanic and knows his stuff. He wrenches on Studes for a living and if something isn't right, he does whatever necessary to make it right. I've known him since I was a little kid and he has yet to tell, show, or explain anything to me that wasn't true. I've spent lots of time with him in his shop (week long intervals) and loved every minute of it, I really learned a lot. Helped him do several things, from torching a Lark, to installing a FOM in a Hawk, to putting windshield reveal moulding in a bullet-nose (experts say it can't be done). He's my first call when I have a technical question and thus far, every bit of his advice has been perfect. (Over the phone he talked me through installing new flanged axles in a 44 rear.) He's the only person, aside from family members, that I will let work on my cars.

[buddymander]

Hmmm, that doesn't explain his rudeness or lack of understanding. MB, do you concur with George that rearend ratios are not related to hard drive and reverse engagement and upshift and downshift harshness? Because that's what this thread's topic has become with relationship to first gear start transmissions. I would like your opinion, please; personal relationships aside.

[mbstude]

quote:Originally posted by buddymander

Hmmm, that doesn't explain his rudeness or lack of understanding. MB, do you concur with George that rearend ratios are not related to hard drive and reverse engagement and upshift and downshift harshness? Because that's what this thread's topic has become with relationship to first gear start transmissions. I would like your opinion, please; personal relationships aside.

I have no experience with that. If I did, I'd tell about it. I was merely stating that George does know his stuff.

Matthew Burnette
Hazlehurst, GA

[buddymander]

Wouldn't you be interested in changing your rear gear ratio if you thought it would reduce your 2-1 shift harshness? Plus it could increase your gas mileage considerably if you're now running anything lower than 3.07. Haven't you ever noticed how a vehicle with a higher geared rearend will engage softer and shift softer than a vehicle with a lower geared rearend? I suppose I could google it and find a mathematical equation that would involve mass and torque and horsepower, but I doubt that type of reasoning is going to change some minds.

[mbstude]

quote:Originally posted by buddymander

Wouldn't you be interested in changing your rear gear ratio if you thought it would reduce your 2-1 shift harshness? Plus it could increase your gas mileage considerably if you're now running anything lower than 3.07. Haven't you ever noticed how a vehicle with a higher geared rearend will engage softer and shift softer than a vehicle with a lower geared rearend? I suppose I could google it and find a mathematical equation that would involve mass and torque and horsepower, but I doubt that type of reasoning is going to change some minds.

No, I've never noticed that. Maybe it "shifts softer" as it's taking more torque from the engine to move the car with the higher rear? I'm not interested in changing anything. My daily driver has a 259 with FOM, second gear start. 3.31 rear end. If I want first gear, I pull the handle down. (Doesn't take that much effort). If I drive it like Studebaker intended, the second gear start works fine and I see no reason to change it. If I wanted to go fast I'd have a stickshift.

[buddymander]

I thought I read in your post on another thread that you had a truck with a harsh 2-1 downshift. Must have been another studebakerer. I like your explanation. Although it sounds like it could be more elaborate, it might be enough to reach some people. But I do believe you have a handle on the concept.

[mbstude]

I'm lost.

Re-read my posts. George has a Hawk with a truck automatic installed, and it's 2-1 downshift is slick and smooth as can be. The "easy" way to convert the 2nd gear start FOM to 1st gear start, is to install a 6 cylinder trans valve body. (6 banger cars started in 1st). This valve body is a bolt in, but you have a very harsh 2-1 downshift. Again, re-read my previous posts.

I do have a truck 1st gear start automatic, but nothing to put it in. My truck is keeping it's stick overdrive. And my sedan (daily driver) just drives too good with its 2nd gear start to mess with anything.

Matthew Burnette
Hazlehurst, GA

[buddymander]

Well you can't expect me to reread all of your posts. If you're happy with your second gear start, that's excellent. I wasn't happy with mine, and a lot of people aren't. I did want to go faster so I got rid of my trans and went with a four speed. The basic question has become one of the feasibility of decreasing the harshness of the 2-1 downshift with the use of a higher geared rearend, since it would also increase gas mileage. See, then you could just install the famed 6 cyl valve body without concern about the harsh shift. So, I'm wondering what rearend ratios were involved with transmissions that had the rough shifting characteristics.

[mbstude]

quote:Originally posted by buddymander

So, I'm wondering what rearend ratios were involved with transmissions that had the rough shifting characteristics.

The one I specifically remember was a '63 Hawk with a 3.31. Standard ratio for a V8 automatic Stude.

Matthew Burnette
Hazlehurst, GA

[buddymander]

That's not a good thing. A 3.31 is a fairly high ratio. And did that valve body have a good 2-1 downshift when it was behind the six? Because the six would probably have had even a lower rear end ratio. (Making for an even harsher 2-1 shift) But that could have been offset by the six's higher stall convertor. I bet the problem is in the application of the low/reverse band. In the six, the l/r band probably isn't applied when the trans is in D and moving forward in low, but the second gear start trans applies the l/r band whenever the trans is in low. Maybe the problem is in the oil routing outside of the valve body in the second gear start trans, allowing pressure to the l/r band simply by being in low. That would cause the l/r band (an engine braking band) to be applied whenever the trans drops out of second and the second gear band is released. I bet in the sixautomatic low is accomplished by only the application of the forward clutch, whereas when the six is in manual low, the l/r band is also applied, providing engine braking. So, then, the question becomes- how do you disable the l/r band when in "D" in the second gear trans with the six valve body?

[STEWDI]

Wow! Lots of discussion!

I do have some relevant experience. We owned a '56 Power Hawk, Vernon built, with a 3.31:1 rear and a factory intalled first gear start, air-cooled ( non-H/D )Flight-o-matic for 11 years. My son has it now and it is still on the road.

The downshifts to first gear (with the gear shift in "D") have always been accomplished smoothly. Actually, the upshifts to 2nd can sometimes be bumpy at a light accelerator position.

Have never had trouble with it and we have known this car since 1978.

Roger "153624" Hill

55 Champion
47 M-5
Izzer Buggy
Junior Wagon

[buddymander]

Small changes to the kickdown can smooth things out sometimes. I wonder if anybody out there has both a six cyl case and a second gear start case to compare the oil feed holes to the low/reverse band. You can shoot air into the holes near the rear pan rail to see which one applies the band. I'm convinced that it's the application of the l/r band that makes the 2-1 downshift harsh.

[StudebakerGeorge]

Well, all of a sudden mr buddymander has 'discovered' that indeed the band causes the harsh downshift...imagine that!
Maybe he finally READ what I was saying. I suppose the next thing he will also 'discover' was what I was said about the HD watercooled units and such. Why he might even 'discover' the reason they have such a smooth 2-1 downshift...
The forum waits on pins 'n needles for his next big 'discovery'


StudebakerGeorge