700R4 trans

[chrismoore701]

I am getting ready to buy a 700R4 trans and want to be sure it will work with my set up. I hear it is from the early 80's and does not have the electronic shift. I have a 79 stepside and plan to build a 420 hp 383. will this work? I plan to have it rebuilt

[gchemist]

Don't buy a 82-84 model. Buy a 85 and later model. Even if it has an electronic speedo, you can convert it back to gears.
The custom 700R4 in my truck is a Camaro 85 core. It cost me over $1700. I can beat on it all day with my ZZ4.

[kelsfine69]

Is it easy to conver back to gears?

[gchemist]

Yes. You replace the driven gear housing and use the proper driven gear.
http://www.transmissioncenter.org/70...ometer%20Parts

[chrismoore701]

how do you tell the years?

[kelsfine69]

Originally Posted by gchemist

Yes. You replace the driven gear housing and use the proper driven gear.
http://www.transmissioncenter.org/70...ometer%20Parts

OK next question, is it the same output shaft? Can the trans be converted without taking the whole thing apart. I have newer(93) 700r4 with the electronic speed sensor and I wish to rebuild it and then swap it over to my 87 and change the tailshaft housing and gear... if its possible?

I know, I know hijacked thread

[gchemist]

Yes. Remove the tail housing. It is held with four bolts. Once you remove it, you'll see the drive gear. You don't need to replace the drive gear unless you need to calibrate your speedo. Read this: http://www.73-87.com/7387garage/drivetrain/spdgears.htm
Since you take off the tail housing, replace the o-ring at the end. The o-ring cause oil leak at the yoke.
http://www.73-87.com/7387garage/drivetrain/yokeleak.htm

Note the driven gear housing comes in two sizes. You need the correct housing based on the driven gear tooth count.
http://www.73-87.com/7387garage/drivetrain/speedo.htm

[kelsfine69]

So I can just swap the speedo gear over to the new trans and swap the housing as well. Seems simple. Is ther some sort of reluctor wheel on the electonic speedo trans output shaft that i have to remove?

[chrismoore701]

I don't mind hijacked threads the more questions answered the better, still need my though on how to tell the difference in years

Chris

[kelsfine69]

88+ had electric speedo Im pretty sure

[gchemist]

On the THM700-R4 the VIN is either stamped onto a boss behind the bellhousing flange on the passenger side, just above the pan on the drivers side, or just behind the governor cover, stamped vertically where the case meets the tailshaft housing.
Prior to 1967, transmission ID numbers contained the plant prefix code, month and date of production (expressed numerically) and a shift code (D = Day, N = Night). From 1967 on, the ID number contained the transmission type or plant prefix, Date (coded below) and a shift code. The constants in decoding the trans ID number are the date the transmission was produced.

Pre-67 Example: C213N - (C = Cleveland Powerglide, February 13, Night Shift)
Post-67 Example: P9E03 - (P = TYPE, 9 = year (1969), E = Month, 03 = Day of Month)

Month code: (NOTICE this is NOT in alphabetic order)
A = Jan, B = Feb, C = Mar, D = Apr, E = May, H = Jun, K = Jul, M = Aug, P = Sep, R = Oct, S = Nov, T = Dec
http://www.nastyz28.com/chevy-transm...tification.php

How many splines on the input shaft?
27 splines for 82-84 tranny's.
30 splines for 84 and later models.
85 and later 700R4 are the best to rebuild.
87 and later models are the most reliable in stock form.