4+3 Tranny swap to ZF 6-speed????
10-01-2015, 04:18 PM
#1
Advanced
Thread Starter
4+3 Tranny swap to ZF 6-speed????
Hello out there in Corvetteland,
I do not know if this has been discussed before, so if it has, please forgive this post.
I have a 1987 C4 with the Nash 4+3 Tranny. I am not really a fan of the 4+3. I have been having OD issues. Slipping in and out and only engaging smoothly on cool days.. so with this in mind I have been researching my options.
Does anyone know if it is possible, or worth the trouble, to replace the Nash with the ZF 6-speed.. AND.. with this, would I have to change the axle ratio.. and drive shaft?
Is the ZF a better tranny?
I do not know if this has been discussed before, so if it has, please forgive this post.
I have a 1987 C4 with the Nash 4+3 Tranny. I am not really a fan of the 4+3. I have been having OD issues. Slipping in and out and only engaging smoothly on cool days.. so with this in mind I have been researching my options.
Does anyone know if it is possible, or worth the trouble, to replace the Nash with the ZF 6-speed.. AND.. with this, would I have to change the axle ratio.. and drive shaft?
Is the ZF a better tranny?
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LovingMyC4 (10-01-2015)
10-01-2015, 05:15 PM
#3
Advanced
Thread Starter
http://members.cisdi.com/~anesthes/zf6/
Allot of good information, I decided to keep my 4+3, fixed a leak and actually have grown to really like it.
Allot of good information, I decided to keep my 4+3, fixed a leak and actually have grown to really like it.
10-01-2015, 06:05 PM
#4
Le Mans Master
There's a sticky on a swap done by another poster at the top of this section. I went ZF from 700R4 but if I had to do it again, I'd probably look at T56 transmission options. Fantastic transmission but too much "voodoo" inside the gearbox, so if it needs some refurbishing, there are a few specialists who can handle it but it's a bit of an unspoken C4 rule the average gearhead doesn't rebuild their own ZF.
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LovingMyC4 (10-01-2015)
10-01-2015, 10:36 PM
#5
Racer
Have you looked into a Tremec swap? I had a TKO600 installed last year because of the same issues with the OD unit on my DN4+3.
It's a bit costlier, but the kit makes it easy to install.
I thought about rebuilding - hard to find someone that has worked on the 30 year-old DN 4+3 unit. And from what I am told the ZF6 and T56 need a lot of work to get them to fit. It's workable, but I wasn't doing the install and that would have lead to a lot of labor charges.
I bought mine from Silver Sport Transmissions. They're very good and easy to work with.
http://shiftsst.com/gm-corvette-c4-1...88#tko-5-speed
It's a bit costlier, but the kit makes it easy to install.
I thought about rebuilding - hard to find someone that has worked on the 30 year-old DN 4+3 unit. And from what I am told the ZF6 and T56 need a lot of work to get them to fit. It's workable, but I wasn't doing the install and that would have lead to a lot of labor charges.
I bought mine from Silver Sport Transmissions. They're very good and easy to work with.
http://shiftsst.com/gm-corvette-c4-1...88#tko-5-speed
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LovingMyC4 (10-02-2015)
10-02-2015, 01:58 AM
#6
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Thread Starter
Have you looked into a Tremec swap? I had a TKO600 installed last year because of the same issues with the OD unit on my DN4+3.
It's a bit costlier, but the kit makes it easy to install.
I thought about rebuilding - hard to find someone that has worked on the 30 year-old DN 4+3 unit. And from what I am told the ZF6 and T56 need a lot of work to get them to fit. It's workable, but I wasn't doing the install and that would have lead to a lot of labor charges.
I bought mine from Silver Sport Transmissions. They're very good and easy to work with.
http://shiftsst.com/gm-corvette-c4-1...88#tko-5-speed
It's a bit costlier, but the kit makes it easy to install.
I thought about rebuilding - hard to find someone that has worked on the 30 year-old DN 4+3 unit. And from what I am told the ZF6 and T56 need a lot of work to get them to fit. It's workable, but I wasn't doing the install and that would have lead to a lot of labor charges.
I bought mine from Silver Sport Transmissions. They're very good and easy to work with.
http://shiftsst.com/gm-corvette-c4-1...88#tko-5-speed
10-02-2015, 08:16 AM
#7
what about the Richmond 6 speed swap ? super easy, all you have to do is modify the floor and change the yoke
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LovingMyC4 (10-02-2015)
10-02-2015, 11:19 AM
#9
The following 2 users liked this post by project C4:
LovingMyC4 (10-02-2015),
yakmastermax (12-13-2023)
10-02-2015, 11:51 AM
#10
Melting Slicks
I liked the 4+3 but understand. It'll be way cheaper to do whatever the Nash needs, even IF a rebuild. It may just be low on fluid or worse, of course, expending oh the historical use and mx.
That said, I finally opted for the ZF6-40 over any 5-spd. but they are pricey to buy and fix and the fitment is not easy. I had ZF Doc do his magic on it. The shorter driveshaft is the easy part.
I changed the rear ratio for a few reasons specific to my car but it's not required.
That said, I finally opted for the ZF6-40 over any 5-spd. but they are pricey to buy and fix and the fitment is not easy. I had ZF Doc do his magic on it. The shorter driveshaft is the easy part.
I changed the rear ratio for a few reasons specific to my car but it's not required.
10-05-2015, 01:24 PM
#11
Advanced
Have you looked into a Tremec swap? I had a TKO600 installed last year because of the same issues with the OD unit on my DN4+3.
It's a bit costlier, but the kit makes it easy to install.
I thought about rebuilding - hard to find someone that has worked on the 30 year-old DN 4+3 unit. And from what I am told the ZF6 and T56 need a lot of work to get them to fit. It's workable, but I wasn't doing the install and that would have lead to a lot of labor charges.
I bought mine from Silver Sport Transmissions. They're very good and easy to work with.
http://shiftsst.com/gm-corvette-c4-1...88#tko-5-speed
It's a bit costlier, but the kit makes it easy to install.
I thought about rebuilding - hard to find someone that has worked on the 30 year-old DN 4+3 unit. And from what I am told the ZF6 and T56 need a lot of work to get them to fit. It's workable, but I wasn't doing the install and that would have lead to a lot of labor charges.
I bought mine from Silver Sport Transmissions. They're very good and easy to work with.
http://shiftsst.com/gm-corvette-c4-1...88#tko-5-speed
Did you also replace the clutch with Silver sports clutch kit?
10-05-2015, 02:38 PM
#12
Racer
Yep. I ordered the one suggested on the site.
I did have one issue thou. I could not get the speedometer to work with the Tremec. They supply the Dakota digital interface, but my mechanic just could not get it to sync. I was planning on getting the Vettaid analog dash so I opted to have them installed. Now everything works.
My next upgrade will probably be a LS swap next year. Which means another new clutch and bell housing.
I did have one issue thou. I could not get the speedometer to work with the Tremec. They supply the Dakota digital interface, but my mechanic just could not get it to sync. I was planning on getting the Vettaid analog dash so I opted to have them installed. Now everything works.
My next upgrade will probably be a LS swap next year. Which means another new clutch and bell housing.
10-08-2015, 03:57 PM
#13
Le Mans Master
Look into your existing 4+3. It's a great transmission if properly maintained. It may just need a fluid flush. If you're going to pay someone else to do the work, it'll cost a pretty penny. Doing it yourself....unless you enjoy that stuff, I would avoid it. Not for everyone.
I just installed my ZF (again) after I had a grinding clutch that spec thankfully did right by me as a customer and sent a replacement set. Wrestling a 140+ pound transmission into place on your back, even with a trans jack, is not for everyone. My body is toast after buttoning everything back up but very satisfying knowing I installed it myself.
All the major hardware to do the swap will be at least $1500. Then you have to come up with a clutch master, slave, the line between the two (line is $100), clutch kit and other nickel dime stuff. I'd advocate the six speed if this car has sentimental value or you have a different engine combo in the future to work with it. That's where you would truly benefit from the six speed.
I just installed my ZF (again) after I had a grinding clutch that spec thankfully did right by me as a customer and sent a replacement set. Wrestling a 140+ pound transmission into place on your back, even with a trans jack, is not for everyone. My body is toast after buttoning everything back up but very satisfying knowing I installed it myself.
All the major hardware to do the swap will be at least $1500. Then you have to come up with a clutch master, slave, the line between the two (line is $100), clutch kit and other nickel dime stuff. I'd advocate the six speed if this car has sentimental value or you have a different engine combo in the future to work with it. That's where you would truly benefit from the six speed.