View Poll Results: Trans selection
Voters: 25. You may not vote on this poll
Keep or dump a 4+3
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Stipulate that the people who answer have actually owned and driven one otherwise you will get caught up in the " all 4+3 are c##p debate " from people who have never seen one , let alone driven one
Depends on your budget and driving style
Depends on your budget and driving style
Last edited by rodj; Apr 13, 2010 at 09:51 PM.
Le Mans Master
Joined: Sep 2005
Posts: 6,551
Likes: 36
From: Jenks OK
If it works, keep it. When you blow it up then figure out what you want. I don't know that I'd replace a broken one but I don't think I'd pull out a working one.
As to what you'd replace it with, I'm partial to manual transmissions but haven't used a zf6 or a richmond so can't speak to the strengths of either one.
As to what you'd replace it with, I'm partial to manual transmissions but haven't used a zf6 or a richmond so can't speak to the strengths of either one.
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
Melting Slicks
Joined: Oct 2000
Posts: 3,426
Likes: 4
From: Heidelberg PA
Cruise-In V Veteran
Depends on what you intend to do with your project. I have gone through two 4+3's, first one I beat to death and the second - bought as a rebuilt unit- I treated like a baby and it still died in less than a year.
It's a neat tranny - pull it and wrap it in cellophane and store it - it might be worth some money some day
Auto - drag racing
6 speed - autocross or spirited street driving
4+3 - great discussion piece -
It's a neat tranny - pull it and wrap it in cellophane and store it - it might be worth some money some day
Auto - drag racing
6 speed - autocross or spirited street driving
4+3 - great discussion piece -
Instructor
Joined: Jun 2008
Posts: 158
Likes: 0
From: Waterford Michigan
I have an 87 with the 4+3 and if money were no object and I had my choice I would replace it with something else. It's not that the 4+3 is a bad transmission, it's just a little clunkier than I like and for my taste I would like something with a shorter throw.
However, money is an object so that's why I still have my 4+3. It still works great and with routine maintenance these things are bullet proof. Like I said before the only reason I would replace it is a matter of driving taste.
However, money is an object so that's why I still have my 4+3. It still works great and with routine maintenance these things are bullet proof. Like I said before the only reason I would replace it is a matter of driving taste.
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
What will you be doing with the car? Return to stock form? track or autocross? Combination?
If the 4+3 works then keep it. The Kiesler TK0 series trans are a bolt in so that makes for an easy swap and will be cheaper than a Richmond. The ZF takes a little work to install on the early cars.
I have had my 87 with the 4+3 for some 6 years now and after lots of track days and autocross it still works fine. The key is to do fluid and filter changes on the OD unit annually or every 12-15K miles.
If the 4+3 works then keep it. The Kiesler TK0 series trans are a bolt in so that makes for an easy swap and will be cheaper than a Richmond. The ZF takes a little work to install on the early cars.
I have had my 87 with the 4+3 for some 6 years now and after lots of track days and autocross it still works fine. The key is to do fluid and filter changes on the OD unit annually or every 12-15K miles.
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Team Owner
Joined: Dec 2007
Posts: 20,974
Likes: 261
Depends on what you intend to do with your project. I have gone through two 4+3's, first one I beat to death and the second - bought as a rebuilt unit- I treated like a baby and it still died in less than a year.
It's a neat tranny - pull it and wrap it in cellophane and store it - it might be worth some money some day
Auto - drag racing
6 speed - autocross or spirited street driving
4+3 - great discussion piece -
It's a neat tranny - pull it and wrap it in cellophane and store it - it might be worth some money some day
Auto - drag racing
6 speed - autocross or spirited street driving
4+3 - great discussion piece -
Driven several, refused to own one, a 6spd is different, and better IMO, but then you may have to do a gear swap unless they can set up you trans with different ratios for you.
I have never driven a richmond, but I would like to.
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Keep it if it works.
I don't like how the Richmond is still external linkage.
ZF6 is great, but is a much more involved swap and very costly to repair.
Keisler is great, but a 5 speed. (Though you may want to call and ask if they could supply you a kit for the T56. I know they looked into it and they offer kits for other makes in varying states of every part supplied, they may be able to set you up with a T56 which would be my first choice.)
What I'd like to know is, could we put a gear vendors OD on the back of our Super T-10s? It would be the same as what we have now except the GearVendors units can take mucho abuse and our OD's are what fail on the 4+3... just a thought.
I don't like how the Richmond is still external linkage.
ZF6 is great, but is a much more involved swap and very costly to repair.
Keisler is great, but a 5 speed. (Though you may want to call and ask if they could supply you a kit for the T56. I know they looked into it and they offer kits for other makes in varying states of every part supplied, they may be able to set you up with a T56 which would be my first choice.)
What I'd like to know is, could we put a gear vendors OD on the back of our Super T-10s? It would be the same as what we have now except the GearVendors units can take mucho abuse and our OD's are what fail on the 4+3... just a thought.
Le Mans Master
Joined: May 2006
Posts: 9,226
Likes: 9
From: Irvine Ca
^^For all that.....why not just make an empty snout for the rear....
Change the gear spread in the Super T10 and bolt an empty shell on the back in place of the O/D unit and just run a 4 speed???
Their is no issue with mine pulling low RPMS at all....so why the close gear ratio to begin with?? Just change 3rd and 4th and delete the O/D all together???
Change the gear spread in the Super T10 and bolt an empty shell on the back in place of the O/D unit and just run a 4 speed???
Their is no issue with mine pulling low RPMS at all....so why the close gear ratio to begin with?? Just change 3rd and 4th and delete the O/D all together???
Team Owner
Joined: Dec 1999
Posts: 34,873
Likes: 487
From: Lacey WA RVN 68-69
NCM Sinkhole Donor
I think that reverse in an integral part of the OD and the overall case length would be a problem not to mention connecting the C-beam to some other tailshaft.
Same with trying something like a GearVendors unit; there has to be a way of attaching the C-beam to the trans assembly. When the Doug Nash OD unit was being developed, the idea was originally for using it in large RV's.
I think that the 4-speed mainshaft is unique to the 4+3 design too. The ratios in each gear of the 4-speed are wider than they were in the old Muncies, especially the version with the 2.20 1st gear. Third gear in the 4+3 isn't that far off from 3rd in the typical Super T-10 or the early Muncies.
The Kiesler trannies can be had with different 5th gear ratios and I believe different 1st gear ratios, so it would be a matter of picking the right ratio for the intended use. Even the DNE 4+3 OD had two different ratios; there was a standard .62 for 84-88and a .68 that was used in the 87 Callaway Twin-Turbo cars.
Same with trying something like a GearVendors unit; there has to be a way of attaching the C-beam to the trans assembly. When the Doug Nash OD unit was being developed, the idea was originally for using it in large RV's.
I think that the 4-speed mainshaft is unique to the 4+3 design too. The ratios in each gear of the 4-speed are wider than they were in the old Muncies, especially the version with the 2.20 1st gear. Third gear in the 4+3 isn't that far off from 3rd in the typical Super T-10 or the early Muncies.
The Kiesler trannies can be had with different 5th gear ratios and I believe different 1st gear ratios, so it would be a matter of picking the right ratio for the intended use. Even the DNE 4+3 OD had two different ratios; there was a standard .62 for 84-88and a .68 that was used in the 87 Callaway Twin-Turbo cars.
Le Mans Master
Joined: May 2004
Posts: 5,381
Likes: 531
How much can the old 4+3s handle power and torque-wise? I've got an 85 issued one that I plan to rebuild. I know they were used with Callaways but I was wondering their absolute limits. It's definitely a unique trans in the Corvette world and gets a bad rap (much like the C4) I think primarily because it's a 4 speed in a 5 speed world during it's premier.
Boasting back in 84 that it was the world's first electronically controlled manual transmission came back to bite GM I suspect. Very misunderstood and I'm still confused about all of the conditions in which the OD kicks in. And it's because there's so much to learn about it, it's the very reason I refuse to write it off.
Boasting back in 84 that it was the world's first electronically controlled manual transmission came back to bite GM I suspect. Very misunderstood and I'm still confused about all of the conditions in which the OD kicks in. And it's because there's so much to learn about it, it's the very reason I refuse to write it off.
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Race Director
Joined: Feb 1999
Posts: 12,772
Likes: 17
From: Indianapolis IN
limited service centers for the ZF too
my TKO swap was @ $2500 using my 4+3 clutch and BH
Also, when you dump $10k in an engine, why would you not buy a good tranny?
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Kieslers are 50% of that, ~$2500-3000.
A zf6 is about 2k and used...
LD85 popped his around 500+tq right?
I've got limited miles on mine with 500+ tq too and I use the clutch and manually turn it on and off, never put power through it while engaged. So far so good. But I'm treating it like a baby.
@1985 Corvette. They were beefed up in 86 or 87 for the Callaways. Sorry. Just be gentle and put money aside for when it goes, if it goes.
Le Mans Master
Joined: Sep 2005
Posts: 6,551
Likes: 36
From: Jenks OK
Does that include the clutch, bellhousing, master cylinder and slave? Central Coaster used to have a good list of parts needed for a swap. I'm sure you can search and find everything you'll need for the swap.