i just finished installing the 4+3 in my 57 Chevy pickup, and have no operation information assistance (no book).
I just have a couple questions:
1. do you just leave it on from second to 4th? OR
2. do you just use it for 4th gear overdrive?
3. Do you switch it off when decelerating? OR
4. do you switch it off after you come to a complete stop?
5. Do you shift, switch, shift, switch like splitting gears?
It seems to me, it is a pretty expensive piece to just wing it, and I don't want to buy another one cause I learned on the "good" one.

A. when it shifts, is it supposed to be sort of abrupt?
This is like dumping the clutch into overdrive, it's not a neck snapper, but it's really felt.
B. When I turn it on, it seemed even if i was light on the gas it was a hard shift.
Thanks in advance, Chris

 

1. I only left it on from 2nd to 4th when I forgot to undo the OD when stopped.

2, Yes, Ideally, when stopped, I would push the button to disengage the OD and then after accelerating in 4th, engage the OD using it like a 5th gear.

3. I didn't switch it off when decelerating, I was never big on engine braking.

4. Yes, after coming to a stop, switch the OD off and then go 1 to 4 and use OD as a 5th.

5. No splitting gears, not necessary and the ratios would be messed up, 2OD is actually just a hair higher than 3rd and 3OD is a hair higher than 4th, you can experiment with it, but I don't think you will like it.

A&B I always clutched when engaging the OD, so it is hard to say how abrupt it should be. Many don't clutch when engaging, but I think it is cheap insurance.

These are just my views, there is no right or wrong way to operate the unit (well there are probably a few wrong ways), do what works good for you.

 

1. You can do it this way. Technically it was designed to be used like this for gas mileage. It is supposed to come on (originally) at 35mph+ in any gear above 1st. BUT, I personally found it worked best if I just went 1-2-3-4 normally and then hit the OD kinda like it was 5th gear.

2. See above.

3. See 4

4. In the vette it used the speed sensor to turn it off below 35 mph. I'd imagine that unless you wired it exactly as it was before you no longer have this feature. I'd definitely turn it off before coming to a stop. It wasn't designed to handle the torque of first gear. Again, I only used mine like a 5th gear, so I'd go 1-2-3-4-OD and if I wanted to decel I'd shift it out of OD and then go 4-3-2-1. I only used mine above 55mph for cruising.

5. This isn't what it was designed for, because there is a lot of overlap. For instance, with a 3.07 rear 3rd in OD is almost equal to 4th without OD. So, if you tried to split gears you'd invariably hit two in a row that were the same and it'd mess you up.

A. Yes, it's quite abrupt. In my 84 when I still had the 4+3 I found it was best to clutch it when shifting into OD. So I'd push the clutch in, hit the OD button, and let the clutch back out like I was shifting into 5th. This way it puts much less strain on everything and doesn't slip the OD plates. Similarly, to shift back down I'd clutch it and release the OD button, then let the clutch back out.

 

I shift 1>2>3>OD>(4OD for over 60), when getting on a highway. OD off when cruising in town. I use the clutch when turning OD off and on.

 

Clutch 1 Clutch 2 Clutch 3 Clutch 4 Clutch (overdrive as 5)

Then when exiting from (Over drive or 5) I also push in the clutch therefor putting me in forth.

 

How are you controlling the 4+3 in your truck?

Are you using the ecm to control or just a manual switch? If using ecm control, which year ecm? The programming varies somewhat year by year.

Here's a chart that may be useful:

http://www.5speeds.com/43table.htm

I've found that the throttle position to disable od while accelerating in first (1st gear look ahead ok) for 87-88 is 40% or 25% (MK2 Z51 cars) instead of 60% as shown in the table.

 

Using a manual switch with a clutch switch to drop out a holding circuit on the overdrive relay.
I have an 89 TPI setup on a 383 with an 89 stick chip that will go in when I get all the overdrive installation finalized. Right now it's a 4 bolt 350.
Chris