4+3 Conversion to 6 speed NEED Help!!!!
Thread Starter
Pro
Joined: Jan 2001
Posts: 603
Likes: 0
From: Windsor, Ontario & Bradenton, Florida
4+3 Conversion to 6 speed NEED Help!!!!
I have purchased a 6 speed and want to convert my 4+3. I have serched the forum but can't find anything on the conversion. Has anyone done this and if so what should I look out for. Any help would be appreciated.
Wayne
Wayne
Burning Brakes
Joined: Aug 2005
Posts: 1,172
Likes: 9
From: '88 TPI L98/HotCam Powell, Ohio
Did you try the advanced search?? 1) click search
2) click advanced (bottom)
3) Type in Zf swap....etc
4) click on archives at bottom
5) click C4 tech.
Central Coaster is the resident guru for the swap, I'm sure he'll check in. If not I'll check back in if I can help.
2) click advanced (bottom)
3) Type in Zf swap....etc
4) click on archives at bottom
5) click C4 tech.
Central Coaster is the resident guru for the swap, I'm sure he'll check in. If not I'll check back in if I can help.
CF Community Team
Joined: Oct 2004
Posts: 19,366
Likes: 5,244
From: Cape Cod, Mass.
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Speak with SK Speed (or performance) in New York. Ask for John. He is the guru on transmission conversions on C4's. Central Coaster is very helpful on this forum also.
Team Owner
Joined: Oct 2004
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From: altered state
St. Jude Donor '05
Team Owner
Joined: Aug 2004
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From: Sussex,Wi
2023 Corvette of the Year Finalist - Unmodified
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Here's a list of stuff, Thanks to CentralCoaster.
89-93 black-tag ZF6
89-93 clutch set
(or use a 94-96 trans with 94-96 clutch)
reuse your flywheel
91-96 bellhousing
89-96 clutch fork and pivot stud
88-91 starter (or LT1 starter will fit '86+ blocks)
89-96 clutch master cylinder
91-96 clutch slave cylinder
91-96 clutch slave hose
89-96 driveshaft slip yoke, install on your stock driveshaft, or just get the whole 89-96 driveshaft.
TH400 rear seal, Timken #9449 (if using a used ZF.) Also, most parts stores have the ZF6 seal wrong in the computer, so don't listen to them.
backup switch connector, a.k.a. horn connector. AcDelco PT1357 or Napa ECHEC11
(5) metric M12 x 45mm transmission bolts
(odd size, get it from mcmaster.com #92820A650)
(6) standard 3/8 x 1-3/4" pressure plate bolts
(odd size, get it from mcmaster.com #92316A630)
17mm allen driver socket attachment for fill & drain plugs. (Available at autozone/kragen in a 3-pack, or mcmaster.com #5571A73)
3 bottles of GM 1052931 oil
or Castrol TWS 10w60 (from your local BMW dealer)
sheetmetal and rivets for patching the trans tunnel, and some extra carpet insulation.
37 tooth speedometer gear GM# 25513044 (for 3.07 ratio)
Reuse your 4+3 speedometer sensor (VSS). Getting the 37 tooth driven gear to mesh requires installing the speedo sensor upside down (180*)and tweaking the hold down clamp a bit. Or you can just get the correct VSS, GM # 25007224
The 3.07 ring/pinion makes 6th gear unusable under 85mph. I recommend upgrading to a 3.45 or 3.55 ratio for L98s.
89-93 black-tag ZF6
89-93 clutch set
(or use a 94-96 trans with 94-96 clutch)
reuse your flywheel
91-96 bellhousing
89-96 clutch fork and pivot stud
88-91 starter (or LT1 starter will fit '86+ blocks)
89-96 clutch master cylinder
91-96 clutch slave cylinder
91-96 clutch slave hose
89-96 driveshaft slip yoke, install on your stock driveshaft, or just get the whole 89-96 driveshaft.
TH400 rear seal, Timken #9449 (if using a used ZF.) Also, most parts stores have the ZF6 seal wrong in the computer, so don't listen to them.
backup switch connector, a.k.a. horn connector. AcDelco PT1357 or Napa ECHEC11
(5) metric M12 x 45mm transmission bolts
(odd size, get it from mcmaster.com #92820A650)
(6) standard 3/8 x 1-3/4" pressure plate bolts
(odd size, get it from mcmaster.com #92316A630)
17mm allen driver socket attachment for fill & drain plugs. (Available at autozone/kragen in a 3-pack, or mcmaster.com #5571A73)
3 bottles of GM 1052931 oil
or Castrol TWS 10w60 (from your local BMW dealer)
sheetmetal and rivets for patching the trans tunnel, and some extra carpet insulation.
37 tooth speedometer gear GM# 25513044 (for 3.07 ratio)
Reuse your 4+3 speedometer sensor (VSS). Getting the 37 tooth driven gear to mesh requires installing the speedo sensor upside down (180*)and tweaking the hold down clamp a bit. Or you can just get the correct VSS, GM # 25007224
The 3.07 ring/pinion makes 6th gear unusable under 85mph. I recommend upgrading to a 3.45 or 3.55 ratio for L98s.
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