4+3 tranny Questions
Thread Starter
Tech Contributor
Joined: Aug 1999
Posts: 15,166
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From: Connecticut, USA
4+3 tranny Questions
Hi guys,
I'm not a c4 guy, I run C3's. I can rebuild just about anything on a C2 or C3 and a guy asked me about rebuilding his 87 4+3. I've done both Muncies and ST-10's but not a 4+3. Is there any info here on this job? Where do you get part kits from? I was told the 4 speed portion is still a ST-10 and the overdrive is similar to a automatic?
I passed on the job but would like to read up on it.
Thanks
Gary
I'm not a c4 guy, I run C3's. I can rebuild just about anything on a C2 or C3 and a guy asked me about rebuilding his 87 4+3. I've done both Muncies and ST-10's but not a 4+3. Is there any info here on this job? Where do you get part kits from? I was told the 4 speed portion is still a ST-10 and the overdrive is similar to a automatic?
I passed on the job but would like to read up on it.
Thanks
Gary
Instructor
Joined: Jul 2000
Posts: 203
Likes: 3
From: Galesburg IL
Here is a pretty good write up on rebuilding the overdrive section.
http://corvetteactioncenter.com/kb/q....php?qstId=115
http://corvetteactioncenter.com/kb/q....php?qstId=115
Melting Slicks
Joined: Dec 2004
Posts: 2,954
Likes: 2
From: Obama=death for America
I've heard that rebuilding a 4+3 is incredibly expensive and difficult. It takes someone with the correct knowledge to correctly rebuild one of these tranny's. I'd advise him to spend a little extra money and ditch the 4+3 and put in a 5 speed.
Instructor
Joined: Aug 2003
Posts: 172
Likes: 0
4 + 3
Can offer minimal input. 4+ 3 was apparently made by Doug Nash Trans. (now Richmond Trans.). The rear, automatic section, I'm told, is rather like the old Powerglide. I recall an ad in the major car mags(Car Craft/Hot Rod) by a guy in N.Y. that offered rebuilding and parts/kits. I'll re-post if I can find any further info.
Another thought is replacement of the 4+3 with a Richmond 6 sp.(expensive but a "bolt in" or Keisler's T-56(same scenerio, in the neighborhood of $3200).
Another thought is replacement of the 4+3 with a Richmond 6 sp.(expensive but a "bolt in" or Keisler's T-56(same scenerio, in the neighborhood of $3200).
Racer
Joined: Dec 2003
Posts: 277
Likes: 3
Originally Posted by gtr1999
Hi guys,
I'm not a c4 guy, I run C3's. I can rebuild just about anything on a C2 or C3 and a guy asked me about rebuilding his 87 4+3. I've done both Muncies and ST-10's but not a 4+3. Is there any info here on this job? Where do you get part kits from? I was told the 4 speed portion is still a ST-10 and the overdrive is similar to a automatic?
I passed on the job but would like to read up on it.
Thanks
Gary
I'm not a c4 guy, I run C3's. I can rebuild just about anything on a C2 or C3 and a guy asked me about rebuilding his 87 4+3. I've done both Muncies and ST-10's but not a 4+3. Is there any info here on this job? Where do you get part kits from? I was told the 4 speed portion is still a ST-10 and the overdrive is similar to a automatic?
I passed on the job but would like to read up on it.
Thanks
Gary
Instructor
Joined: Aug 2003
Posts: 172
Likes: 0
P.s.
For historical info, see Http://corvetteobsession.homestead.com.
Try www.pipersauto.com for possible parts and rebuilt units (this is 5 Speeds by Darrell). Good Luck. The "obsession site" offers some interesting facts(?) about the strength, etc. of the ole 4 + 3.
Try www.pipersauto.com for possible parts and rebuilt units (this is 5 Speeds by Darrell). Good Luck. The "obsession site" offers some interesting facts(?) about the strength, etc. of the ole 4 + 3.
Safety Car
Joined: Dec 2004
Posts: 4,088
Likes: 0
From: Poop land
This might be a little OT, but is a 4+3 a manual or auto? Does it have a torque converter? Any pics on what they look like, e.g. how you shift them? Hmmm... I just wanna fulfill my knowledge about the earlier C4s.
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Burning Brakes
Joined: Jul 2004
Posts: 956
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From: Mesquite Nevada
Originally Posted by xeugep
This might be a little OT, but is a 4+3 a manual or auto? Does it have a torque converter? Any pics on what they look like, e.g. how you shift them? Hmmm... I just wanna fulfill my knowledge about the earlier C4s.
. Personally, I think they are a lot of fun to drive. 
Thread Starter
Tech Contributor
Joined: Aug 1999
Posts: 15,166
Likes: 3,967
From: Connecticut, USA
Thanks guys, I don't usually take in C4 work because I'm not familar enough with them. This guy has over 100k on the car and wants to get the tranny fixed and can't find anyone who will rebuild it. Several vette shops will exchange it. I'll check those leads you gave me
Gary
Gary
Safety Car
Joined: Dec 2004
Posts: 4,088
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From: Poop land
Originally Posted by 87Clwy
It's a manual 4 speed with 'overdrive' in 2nd - 4th gears; thats where the 'auto' part comes in, as well as the name. You shift between 1st - 4th like a regular manual. However thier is a button on top of the shifter you push (without using the clutch) to put it in 'overdrive'. Normally I don't use the over drive in town, only when cruising at hiway speeds. Once in or out of overdrive it will stay there as you shift gears. Also, if you're cruising in overdrive, lets around 65 or so, and jump on it, it will pop out of over drive and give you that 'lower gear boost' to get you up where you need to be . Personally, I think they are a lot of fun to drive.
. Personally, I think they are a lot of fun to drive.
Thread Starter
Tech Contributor
Joined: Aug 1999
Posts: 15,166
Likes: 3,967
From: Connecticut, USA
Originally Posted by steveb
Here is a pretty good write up on rebuilding the overdrive section.
http://corvetteactioncenter.com/kb/q....php?qstId=115
http://corvetteactioncenter.com/kb/q....php?qstId=115
Gary
Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
I've you've done a Borg Warner Super T-10 then you can definitely do the 4-speed part. It uses the CC (2.88 1st gear) gearing setup. The O/D part takes a little patience, but should be doable with a couple specialty tools (or make up your own).
Parts are too bad for it unless you break a major piece like the cluster gear.
Parts are too bad for it unless you break a major piece like the cluster gear.