Is auto to 4spd swap possible?
Thread Starter
Le Mans Master
Joined: Nov 1999
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From: PA
Is auto to 4spd swap possible?
What modifications are required to drop a manual tranny into my car. I was hoping to drop in a used 4spd. I assume I will need to change or modify the crossmember. What else would be required? Also, what tranny do you guys recommend I look for since I am not really sure the of the difference between M-21, M-22, etc?
Safety Car
Joined: Aug 2000
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From: Clymer PA
Re: Is auto to 4spd swap possible? (Brett K)
I thought the Corvettes with automatic transmissions already had the removable crossmember....I could be wrong though. The M22 is commonly known as the "rock crusher." It is supposed to be a stronger design than the M21, partly due to how the gears for the transmission are cut. I'm sure some other forum members will respond soon.
Team Owner
Joined: Feb 1999
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From: Republic of Texas
Re: Is auto to 4spd swap possible? (Brett K)
Yes, you will need a manual crossmember, pedals, clutch, etc.
The difference in the transmissions are that one is a Heavy Duty(M-22) named "Rock Crusher" and the other is a "Close Ratio" M-21 and is a more rare trans.
[Modified by Thad, 9:18 PM 1/28/2002]
The difference in the transmissions are that one is a Heavy Duty(M-22) named "Rock Crusher" and the other is a "Close Ratio" M-21 and is a more rare trans.
[Modified by Thad, 9:18 PM 1/28/2002]
Racer
Joined: Nov 2000
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From: mauriceville texas
Re: Is auto to 4spd swap possible? (Brett K)
why auto to 4spd? for about 3500 in parts and you provide the labor you can put a 6 sp with lower first and a od for hy driving. put one in my 71 and love it. was one of the best mods for the money. 308 rear 70 is 2100 rpm sweet. robert
Drifting
Joined: Mar 2001
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From: Indiana
Re: Is auto to 4spd swap possible? (Brett K)
Other than the fact that the auto crossmember is removable, it is almost identicle to the manual crossmember. The only thing you will need to do to the crossmember is to add two "L" shaped brackets that support the tranny mount bracket that is needed for the manual trannies. This tranny mount bracket hangs over the front side of the crossmember because the manual trannies have a shorter distance to the mounting pad. This bracket uses the two holes on the top side of the crossmember where the TH400 rubber mount now goes as well as the two holes through the "L" shaped brackets that you will be welding on. The yoke will be the same on the M-22 and Borg Warner Super T-10, but you'll need the smaller yoke for the standard T-10, M-20 and M-21. You will also need to weld a bracket to the frame for the clutch linkage. This will go on the frame perpendicular to the hole for the pivot ball that is near the oil filter. It's been a long time since I did mine, but I think you'll also need a different exhaust bracket that mount under the tranny mount. Lets not forget hanging the pedals too. This is definitely the toughest part of the swap. All in all, the swap is not to bad.
Tom
Tom
Team Owner
Joined: Jun 2001
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From: Virginia USA
Re: Is auto to 4spd swap possible? (robert kirk)
Capt. Kirk (like you've never heard that one before :lol: :lol: )
Is the shifter in the stock location or did you have do alot of mods to the interior to fit the 6-speed?? I also have seen people say the trans tunnel has to be widened...is this true. I though about getting a 6-speed but have heard some really expensive sounding things involved. Give us some insite for this mod.
Thanks
John
Is the shifter in the stock location or did you have do alot of mods to the interior to fit the 6-speed?? I also have seen people say the trans tunnel has to be widened...is this true. I though about getting a 6-speed but have heard some really expensive sounding things involved. Give us some insite for this mod.
Thanks
John
Le Mans Master
Joined: Oct 2000
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Re: Is auto to 4spd swap possible? (theandies)
The Richmond 6 speed went into my 1979 automatic C-3 very nicely. The hardest part is changing the pedals. Crossmember is OK-needs a small notch; shifter comes up in the same hole; driveshaft is the same length; uses TH400 front yoke (same as T-10?); all you need is $$$. I'd post pics of the install, but it looks like the home pages are down again around here! #$%^%&$!!
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Team Owner
Joined: Jun 2001
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From: Thomson Georgia
Re: Is auto to 4spd swap possible? (Brett K)
I would like to do a similar change one day....I would love to follow your progress and pics if you decide to do it..I am waiting to come across a really cheap 5 or 6 speed
Race Director
Joined: Nov 2000
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From: Waterloo ontario Canada
Re: Is auto to 4spd swap possible? (Brett K)
Why mess around with a manual clutch. The hydraulic units bolt right in. Even the hole in the firewall is there for the master cylinder. One from a 85 one ton truck fits perfectly with only a linkage modification. A slave cylinder is easily mounted or comes with a used bellhousing.
Why not a T5 ? I know some people are against them but I personnally have used them, still have one in an 11 second mustang and you get a great first gear and a overdrive. I would never go with just a 4 speed. I know an idiot with a nitrous well built 355 and he beats on the car everyday going through 3 sets of tires a summer and blows about one T5 per year. He power shifts constantly and only seems to blow the T5 in third with a missed shift. If you don't beat on the trany a T5 will survive.
Why not a T5 ? I know some people are against them but I personnally have used them, still have one in an 11 second mustang and you get a great first gear and a overdrive. I would never go with just a 4 speed. I know an idiot with a nitrous well built 355 and he beats on the car everyday going through 3 sets of tires a summer and blows about one T5 per year. He power shifts constantly and only seems to blow the T5 in third with a missed shift. If you don't beat on the trany a T5 will survive.
Le Mans Master
Joined: Oct 2000
Posts: 6,209
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From: Texas-out west
Re: Is auto to 4spd swap possible? (Brett K)
not only possible, but very easy if you get all parts from wrecked car, I did it on 73, took weekend. I got everything out of 69 from bellhousing/clutch back to driveshaft and pedals, the hardest part I thougt. I did have to weld clutch Z rod bracket on frame. Good luck. :cheers:
Le Mans Master
Joined: Apr 2000
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From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
Re: Is auto to 4spd swap possible? (Brett K)
Brett why not look at some of the newer O/D automatics ? Have you visited Bowtie Overdrives website ? I seriously considered converting my 4spd to an auto because of the benefits of being able to just put it in gear and slam the gas :D ! The 700R has a lower ratio (? If I got that right?) 1st gear than the 200R so it'll take off harder or spin the tires easier. The 200R has a higher O/D gear so your highway cruising rpm's will be a bit lower for better mpg :) . Depending on your rear gear ratio, might also depend on which tranny would be a better fit. I have 3.90's so I considered the 200R if I had 3.36's I would probably go with the 700R.
Staying with an auto might be a bit easier swap for you, but I would strongly encourage you to look at an O/D for both the performance & economy, probably the best upgrade you can make :yesnod: .
Being that my car is a 4spd, I've decided to stay with the standard shift & go with a Tremec TKO 5spd w/ O/D. :cheers:
Staying with an auto might be a bit easier swap for you, but I would strongly encourage you to look at an O/D for both the performance & economy, probably the best upgrade you can make :yesnod: .
Being that my car is a 4spd, I've decided to stay with the standard shift & go with a Tremec TKO 5spd w/ O/D. :cheers: