73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: chippy on November 16, 2015, 10:38:33 am
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Hi Guys, fairly new to posting.
I did some searching here but did not find an exact answer. I want to know the easiest swap to make to get my girl a 4 speed auto tranny. I dont have anything built, I dont race it. Just want a lower RPM when I take her out for a short trip. I do use her on the farm to haul wood and small loads..
I dont want to mess with computers and all that. Any suggestions or links would be appreciated.
Chip!
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700r4
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700r4
Is it a straight swap? or are there extra parts necessary?
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My question exactly!!!
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There is no such thing as a straight swap. There are always extra parts necessary. But since the 700r4 came stock in a lot of our trucks all the parts needed are easily available. The trans cross member will work but it will need to be moved back a little. The frame should have extra holes already drilled for it. Your driveshaft will probably need to be shortened or go grab one from a truck that came stock with a 700r4 at a junkyard. A 3 speed column will work with the 4 speed. But the little gear indicator thing won't line up.
It's been a long time since I did this swap. But it's not that hard guys.
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Thanks for the info! I will be giving it a go... Was it worth it to you? What was the biggest difference you saw? Thanks again for the information and help.
Chip
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When I did the th350 to 700r4 swap. It was on my dad's truck back in high school for punishment for destroying the th350 in my van. I bought the 700r4 for my van and when my dad found out. He made me put it in his c10 and put his th350 back in my van. His truck was an 82 c10 longbed with a 305 and a 2 barrel, and with the 700r4 his mileage went from 15 mpg to 18 mpg. So I guess it was worth it to him. He drove 120 miles round trip per day.
Now for the truck I have now I went from a th400 to a sm465. And hopefully someday a nv4500.
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turbo 350 to 700r4 was drilling holes in the frame and move back the cross member support for it. A new or cut your current drive shaft. E brake adjustment, truck sells the a new gear selector indicator or junk yard. To use lockup I wired mine to a on/off switch (I drag raced my truck so i wanted it off on the strip) a bracket for the TV cable, depending on what year 700r4, a mechanical or electrical speedo gear housing. Bend the cooler lines. maybe a fitting or two for the lines, other then that should bolt right in. I got mine out of a 92 chevy caprice police interceptor.
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Go with what Gwtt said. if you can find a donor c10 with a 700r4 go with that the newer the truck the better version of 700r4. you can use a 700r4 from 82-93 in 94 is when they became electronically controlled and you need a ecm/tcu for them. in 87 they changed names to the 4l60 but its still a 700r4 just named different and built different. if i was to go with a 700r4 i would go for a burnt up one at core price (a few hundred $)and have it built. make sure you do some research on the tv cable and how to set it up right cause that would be the nuber 1 failure for new or newly swapped trans
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great info! working on finding one now!!
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I read through this quickly so it may have been said but what I remember the TH350 was gone by 1986. If you had a 3 speed automatic it was a TH400, even behind the 4.3L V-6. If it was a factory installed TH350 it may have been a real early 1986 production. The transmission is withing 1/4" the same length and drive shaft mods are not needed at all. In my case (1985) holes had to be drilled in the frame for the new cross member location. MY $.02
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My truck is a 85 and came with the 700R4 but its my understanding that if you have the long shaft TH350 you can reuse your stock driveshaft. You will need the converter to go with the transmission. Cooler lines will work but may need to be tweeked. You will have to move the crossmember. You will need the TV cable bracket also. Everything else from the 3spd should work. If you have a TH400 then you will probably need a driveshaft. Cant remember the length on the TH400 compared to the 700R4. The 700R4 didnt change to the 4l60 until 1990. What changed in 1987 was going from a 27 spline input and different front pump to a 30 spline input and a better front pump and stronger internals. If you want to keep your mechanical speedo you will need a unit that came with a mechanical speedo or do the conversion.