700r4 Swap in a 84.
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Pro
Joined: Dec 2002
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From: 84 383 XFire Chandler, AZ
700r4 Swap in a 84.
A little history - I have a 84 and I am having a 383 built. I am not sure what it is going to put out but I am sure it will be alot more that the original 205hp 350. Anyway, I got a real good deal on a 86 700r4 30 spline thinking I would just swap the input shaft and pump (take the 86 and put it in the 84) I was told by a tranny guy that the parts are interchangeable. But I was thinking why go to all that work if I can just swap the tail housing and beef up the 86 tranny to survive the 383. Am I all wet or am I on the right track?
I don't know that much about auto transmissions so any enlightenment the learned ones of this forum can pass on is much appreciated.
I don't know that much about auto transmissions so any enlightenment the learned ones of this forum can pass on is much appreciated.
Race Director
Joined: Feb 2004
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Be sure to also upgrade the foward sprag assembly. Convert it to the 87 and up style and be sure to change the input sun gear. This was THE big change for 87 and up that gave them increased torque capability. Many , many changes between 84-88. It will likely be more cost effective to buy an 87 1/2 -92 (aux valve body) trans and swap in your governor, servo , output shaft, tailhousing, wot upshift valve and speedo gears.
Drifting
Joined: Feb 2004
Posts: 1,277
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From: Santa Maria CA
YO, Elk whats up bud?! i am doing the same thing you are with an 88' trans i bought from anther forum member. my friend has a 00' Formula LS1 and blew his trans,sent it to a place here in California to have it gone through with a kit from PRO-BUILT. its the same kit BEN73 used for his 84'. my friends tranny hits hard and is very drivable even with a TCI 10" 3800 stall. he also did a smart thing and bought a hardened input shaft in it becasue of the weak ones that were stock. good luck. 
Thread Starter
Pro
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From: 84 383 XFire Chandler, AZ
Pete - Thanks for the info. I am going to run with the 86 tranny for now, I have it sitting on the floor and if it I blow it up I will definately look into a later model year. It has already been rebuilt with the Corvette servos, bands, and a bunch of other upgraded stuff. My main question is whether or not I can just swap the tail sections and go from there.
Hey Shin - My motor with be done on 3/18 and I will be doing the swap after that. Hopefully I will get it swapped between then and mid April.
Hey Shin - My motor with be done on 3/18 and I will be doing the swap after that. Hopefully I will get it swapped between then and mid April.
Race Director
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From: The Top of Utah
Originally Posted by elkabong
My main question is whether or not I can just swap the tail sections and go from there.
RACE ON!!!
Thread Starter
Pro
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From: 84 383 XFire Chandler, AZ
CFI - Yep the 86 trans is not out of a Vette. It was in a 80 Vette for a while but the guy put in a TH350 becasue he did not want to deal with the converter lockup. The trans was completely gone through, new clutch pack, trans go shift kit and it has less that 500 miles on it. I am still going to tear it apart and check things out but this is a case where I am out of my element - but there is nothing like learning new things.
I have more research to do and more questions to ask.
I have more research to do and more questions to ask.
Race Director
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I did not know that the 86 trans was fresh. I thought your were about to start a build up. You are probably right, it will be more cost effective to make the 86 work. You will not be able to upshift to 4 th gear at wide open throttle unless you change the tv valve. Some guys care about this feature and some do not. If you do it is a simple to do, $80 swap. The 86 sprag will probably hold up under these power levels. You may want to stick your corvette governer in it so that you cam maintain your current shift points. 86 unit will likely shift lower.
Racer
Joined: Jun 2004
Posts: 440
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From: Grapevine Texas
Elk,
Here is a link for you for the parts on the 700r4, these are the best avail that I know of and some of these parts were actually designed by these guys. I will tell you, while your in there, you can put all of the hard parts in you want, but if you do ot go with good clutches and band, you will be on the side of the road with that stroker...I was. Also, don't ever shift into fourth full throttle...a few times of doing this, you will burn the band and fry the 3-4 clutches...these guys will tell you the same. With 300 hp, you can, over 375-400, I wouldn't do it.
http://www.transmissioncenter.net/highperflist.htm
Here is a link for you for the parts on the 700r4, these are the best avail that I know of and some of these parts were actually designed by these guys. I will tell you, while your in there, you can put all of the hard parts in you want, but if you do ot go with good clutches and band, you will be on the side of the road with that stroker...I was. Also, don't ever shift into fourth full throttle...a few times of doing this, you will burn the band and fry the 3-4 clutches...these guys will tell you the same. With 300 hp, you can, over 375-400, I wouldn't do it.
http://www.transmissioncenter.net/highperflist.htm
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Drifting
Joined: Aug 2000
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From: Houston, TX
Maybe a helpful link
http://www.4wheeloffroad.com/techarticles/63498/
I know it is for a truck, but it is a tech artilce on a 700r4 rebuild. Had a link to a company that sells the video of a 700r4 rebuild, but the link is no longer current. Have seen the video for sale on ebay and some tech stores may have them too. Good Luck
http://www.4wheeloffroad.com/techarticles/63498/
I know it is for a truck, but it is a tech artilce on a 700r4 rebuild. Had a link to a company that sells the video of a 700r4 rebuild, but the link is no longer current. Have seen the video for sale on ebay and some tech stores may have them too. Good Luck
Thread Starter
Pro
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From: 84 383 XFire Chandler, AZ
Would something like this be compatible.
eBay Auction Example
Also from what I have read the first digit of the number on the passenger side has a 4 so according to what I have read the trans is a 84 and not a 86.
eBay Auction Example
Also from what I have read the first digit of the number on the passenger side has a 4 so according to what I have read the trans is a 84 and not a 86.
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Very likely, but what's the point? I thought you were ready to change the tail shaft housing on the '86 trans and bolt it in. From what I've understood you to say, that's your best route.
RACE ON!!!
[Edit] I clicked your link and hit reply", without reading the last paragraph. Do either your trans or the new trans have a 30 spline input? That would make the better candidate. The change from 27 to 30 spline was made during the 1984 model year. ANYthing 1985 and up will have 30 splines.
RACE ON!!!
[Edit] I clicked your link and hit reply", without reading the last paragraph. Do either your trans or the new trans have a 30 spline input? That would make the better candidate. The change from 27 to 30 spline was made during the 1984 model year. ANYthing 1985 and up will have 30 splines.
Last edited by CFI-EFI; Mar 4, 2005 at 07:45 PM. Reason: [Edit]
Thread Starter
Pro
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From: 84 383 XFire Chandler, AZ
CFI - Right now I am just trying to figure out how compatible everything is. Based on the numbers on the passenger side of the other tranny it is a 84 and not 86 but it does have a 30 spline input shaft which is really what I was after. The other thing is I still need to research the differences in the valve bodies. Vette valve bodies are different. So, it may be better to just take out the input shaft and pump form the other tranny and put it in my original.
Race Director
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Be careful. Swapping sub assemblies from later years can be very risky. I had to buy a special book just to describe subtle differences from year to year and model to model. Consult a pro . You may lay an egg that you cannot hatch. I am speaking from experience. Also be very careful how much money you wrap up in an 84 trans. There were many dozens of design changes in the 700r4/4l60 transmissions. Trying to bring an 84 model up to 87 1/2-92 specs is terribly expensive to do. This is why I recommended the 87 1/2 and up as a starting point in my earlier post. I am certainly not trying to tell you what to do. Just be careful what you do to avoid the pitfalls I mentioned.
