Comparing 6 speed to 4+3 manual.

[1989 406]

When I get a Corvette it will be a manual. I would prefer the 6 speed, but my pockets may only be able to afford the 4+3.

I am very unfamiliar with the 4+3. I never drove one and do not even still understand the concept of how it works. I never met anyone who had one.

My question is would you let the 4+3 hold you back until you could afford a 6 speed. I drove the 6 speed and liked it.

Again very green about the 4+3.

Would like to hear comparisons between the two.

If money was not an option I would not have to post.

 

[Hib Halverson]

The 4+3, which is a Warner Super T10 four-speed mated to an electro-hydraulic overdrive unit, is an inferior transmission when compared to either the 89-96 ZF S6-40 six speed or the TREMEC T56 used from 97-09.

 

[LLC5]

Wait for the 6 spd. The 4+3 was an after thought, it's basically an overdrive unit bolted to the back of the transmission. No comparison.

 

[JimBobC4]

The feel of the 6 speed is far better than the 4+3. The 6 speed has shorter gear throws and a much more precise gear selection mechanism.

If you have ever driven an older GM small block 4 speed car, then you have a good idea of what the 4+3 feels like.

The 4+3 is tolerable anda useable tranny but the 6 speed is MUCH more crisp during shifts.

 

[MBDiagMan]

I have driven both extensively but currently have a 4+3. This is a transmission that got a bad and undeserving reputation. This was largely due to the people who called themselves techs but proved to be only parts changers.

Any "tech" who cannot, with 20 or 30 minutes of reading, understand this unit enough to accurately troubleshoot it, should be ashamed of themselves and change their title to "parts changer."

If this transmission is properly serviced, particularly the OD unit, and is not driven totally crazy, it will live forever.

My 88 has 127,000 miles with the original 4+3 and it has been removed once in its life and that was only for a clutch job. I have replaced the switch at the bottom of the stick and the coil in the pan. Both of these were SIMPLE and inexpensive repairs.

A lot of people who don't like driving one of these is just not a serious stick shift driver. If they don't understand how to drive it properly, it will drive them crazy quickly. It will automatically shift to OD in any gear and kick out when the throttle stepped on UNLESS you know to lock it out with the button. The button is part of the fun of driving one of these.

Here's the way I drive it and find it quite enjoyable:

I start the engine, put on my seatbelt and otherwise get ready to roll. I then hit the OD button on top of the stick which locks out the overdrive. I then take off and run through the gears and once wound out in fourth, I simply hit the button with my thumb and it drops in overdrive.

If I want to pass someone I hit the button again to kick it down. If you would rather, you can simply step on it and it will kick down for passing and then automatically drop back in OD after you level off.

The complexity of the unit consists of a switch at the base of the shifter that connects to the button mechanically. This feeds the computer. The computer than sends a one wire signal to a connection on the transmission. At the transmission this connects electrically through a simple pressure switch that actuates a coil that pulls a check ball. THAT IS ALL THERE IS TO IT!!!!!

The button simply TOGGLES it in and out of overdrive. Hit it once it enables the overdrive, hit it the next time and it kicks it out, the next time it kicks it in. Very simple.

Again any tech that can't understand this simple circuit should find another line of work.

My advice to you in your situation is; if you find a nice, well cared for and PROPERLY MAINTAINED 4+3 in good working order, drive it using my method. If you like it and IT IS IN GOOD CONDITION, buy it and enjoy it. You might find that you don't care to find a 6 speed after that.

I think you are very wise to be looking only at stick shift Vette's. To me, driving a sports car without a manual transmission is like hiring a prostitute with no "you know what" between her legs.

Hope this helps you.

 

[JimBobC4]

If this transmission is properly serviced, particularly the OD unit, and is not driven totally crazy, it will live forever.
QUOTE]

I disagree, I've driven a 4+3 totally crazy several times and didn't break it !

I've driven more than one like a rental. :W

I've said it many times on this board, an L98 with a 4+3 is a tire smokin' fun machine.

 

[Oldskool153]

I have a 4+3 and as paranoid as I am about the bad reviews I must agree it is alot of fun, I drive mine the same mbdiagman except when I wind out in 4th I push the clutch down to take the load off the OD, than I hit the button and release the clutch. Finding a system that works is gonna be hard but I also had my OD disconected for about a month and I used it as a 4 speed with no OD... If i could go back in time i would wait for a 6speed but im paraniod about my trans. the 4+3 is a cool trans and alota fun too tho, Good luck which ever way you go

 

[vetteoz]

This is a transmission that got a bad and undeserving reputation. .................
A lot of people who don't like driving one of these are just not a serious stick shift driver.

No different than driving a early Camaro/ Corvette 4 spd with the now outdated external linkages, BUT with the fuel saving features of an overdrive.
Best of both worlds

 

[G Winter]

I have never driven a 4+3 but have driven 4 speeds many miles and many 1/4 miles. I think the 6 sp shifts a little smother and easier.
From everything I have read, it can't be that difficult to rebuild the overdrive unit. Sounds pretty simple compared to the 350 and 400 THs.

Glenn

 

[MBDiagMan]

I've never rebuilt a 4+3 OD unit, but I've done a limited amount of Turbo 350 and 400 work. All that is in the OD unit is a clutch pack and a planetary. The valve body is so simple, it's not really correct to call it a valve body. I fully expect that the clutch pack and planetary are exactly like those units from a particular GM automatic or another.

With a few basic A/T tools I expect that it would not be all that difficult.

The planetary and clutch pack part of these transmissions was not what typically baffles the techs. They just couldn't run down a one wire circuit. Electrically this OD unit and it's supporting switches are simpler than a headlight circuit, but lots of techs just weren't up to the task. Unfortunately it says alot about the techs of that era.

I don't THINK that we are as bad off with automotive technophobia in the dealership service departments today. It is MUCH more common to have electronic savvy guys in todays shops.

Oldskool,

You don't have to use the clutch to baby the OD, just lighten up on the throttle a bit and it will minimize the impact of the shift.

 

[Oldskool153]

Oldskool,

You don't have to use the clutch to baby the OD, just lighten up on the throttle a bit and it will minimize the impact of the shift.

really? Corvette Paramedics (my normal goto guys) told me that the car needs to be stopped or the clutch needs to be to the floor when I hit the button, this struck me as odd considering if i floor it than let up in 4th the car puts itself in and out of OD, and that is pretty much the same thing as me hitting the button right?? I just wasnt sure because they told me that they had someone burn up an OD by using the button when slowing down, in stead of downshifting he would kick it out of OD at everylight and let the car slow down..

 

[Oldskool153]

Also Mbdiagman quick question that I could never get fully answered on this site or by any of the Corvette techs I know... when I had the OD unplugged for about a month, does driving it as a 4spd with out the OD hurt the bearing inside the OD? I've had guys tell me "yes because when the car is in OD the bearing stops spinning and using it as a 4spd wears it out", and I've had other corvette techs guys tell me "no, it cant hurt anything and people drive them as 4spds for years when they cant get the OD to work"..mines connected now but I was j/w cuz i could never get a straight answer

 

[vdogamr]

I have the 4+3. I drive mine just like the others here (including pushing in the clutch for the swaps). And I love it. Every stick shift takes some getting used to and this one took a little longer.

If you care about the shifting speed, in "101 projects for your Corvette" they have a project in there to make the shifting smoother. Like most things in the book it isn't well explained, but it can be done.

If you are debating between a 4+3 and a 6 speed, you are debating between an 84-88 or an 89-96. I would think there are better reasons than the type of manual transmission to pick the newer model. Like the type of engine. But that is just me.


But I would like to put my vote in for the 4+3 being a fine transmission.:cool

 

[KANE]

When I get a Corvette it will be a manual. I would prefer the 6 speed, but my pockets may only be able to afford the 4+3.

I am very unfamiliar with the 4+3. I never drove one and do not even still understand the concept of how it works. I never met anyone who had one.

My question is would you let the 4+3 hold you back until you could afford a 6 speed. I drove the 6 speed and liked it.

Again very green about the 4+3.

Would like to hear comparisons between the two.

If money was not an option I would not have to post.

Buy the NICEST one you can afford- you'll never go wrong. Don't be tempted by a lesser Vette when you can afford a nicer one. Don't be in a rush to buy either.


IMHO, the 4+3 is kinda neat. It was only used on the Vette and stands as a period correct option. Yes, it is a bit different- but on a weekend car maybe it will be just different enough that it is fun for you. You could always chose not to use the OD until you are comfortable with it.

 

[MBDiagMan]

Buy the NICEST one you can afford- you'll never go wrong. Don't be tempted by a lesser Vette when you can afford a nicer one. Don't be in a rush to buy either.


IMHO, the 4+3 is kinda neat. It was only used on the Vette and stands as a period correct option. Yes, it is a bit different- but on a weekend car maybe it will be just different enough that it is fun for you. You could always chose not to use the OD until you are comfortable with it.

Very good advice, but I would word it a LITTLE differently by adding this:

The three most important considerations when buying any used car are:

condition
Condition
CONDITION!!!!!!!!!!!!!!!!!!


The shifting in the OD unit is no different than the shifting that takes place in any of millions and millions of automatic transmissions on the road. There is a clutch in the OD unit. Using your foot operated clutch is redundant. NOW, that statement is said with reasonable driving in mind. If you're trying to drive like Rolf Shumacher then you may be applying too much torque for it's long term health.

I would be surprised if disconnecting the OD and running without it would hurt anything. It would just run up your fuel bill.

When I approach a stop sign, traffic light and such I just let off the gas and slow down. When I get ready to change gears to which ever gear I chose to accelerate back to speed in, I press the OD button as I'm in neutral while on the way to that gear. It's a little awkward, but after doing it some you will get used to it.

 

[vetteoz]

When I approach a stop sign, traffic light and such I just let off the gas and slow down. When I get ready to change gears to which ever gear I chose to accelerate back to speed in, I press the OD button as I'm in neutral while on the way to that gear.

O/d should automatically drop out when you come to a stop or accel hard.
Different setting vary by year
http://www.5speeds.com/43table.htm

 

[MBDiagMan]

Of course it would drop out automatically, but then you are allowing the computer to control the OD making it a really screwy thing to drive.

By toggling the OD out when slowing, you then have a manually controlled four speed with which you can decelerate and accelerate until you get back to highway speed and chose to allow it to drop in overdrive.

Anyone who never touches the overdrive button and lets the computer control the overdrive is missing out on the fun of driving one of these machines. In fact if you never touch the OD button, I don't see how you can stand to drive the thing.

Now that you bring this up, I'll bet the undeserved poor reputation is partly from those who have driven one without ever touching the button. If the button weren't there to lock out the OD I wouldn't have kept mine two weeks.

If there is anyone who is driving a 4+3 and has never locked out the OD, try my method. Start the car and hit the button, then drive it through the gears unless you are somewhat wound out in fourth, THEN hit the OD. This will open up a whole new world for you.

 

[vetteoz]

Now that you bring this up, I'll bet the undeserved poor reputation is partly from those who have driven one without ever touching the button. If the button weren't there to lock out the OD I wouldn't have kept mine two weeks.

Out of interest just pulled out my '87 owners manual
It states ; has computer controlled O/d ....the O/d may be turned off...if engine braking is needed O/d may be turned off ,be sure to turn O/d back on IMMEDIATELY afterwards"

All those poor souls that never had the real enjoyment of driving the 4+3!

I fully expect that the clutch pack and planetary are exactly like those units from a particular GM automatic or another.

FYI;http://www.5speeds.com/nash.htm

 

[johnny80]

I have had my 88 for the past 8 years. I have to say that I also enjoy the 4+3. It took a bit getting used to but once you learn the system, it is a pleasure to drive. I have 118,000 miles on mine at it's been running great. What ever choice you make, as long as you perform the basics to keep it in shape, it will run great.

 

[Glava2876]

My 84 has an OD switch in the console that you either turn on or off -I almost never turn the OD on and this Z51 lumber wagon with fat tires is a HUGE blast!!!
I have a question; Someone above said that this is a Borg Warner T-10 with an OD unit -is that correct?
Thanks,
Glen