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700R4 Transmission Swap

Time:2017-10-13 00:36Turbochargers information Click:

Transmission 700R4 swap

GM 700R4 Trans. Info

The 700R4 is a good transmission for a retrofit into an older car. It has a 0.7 to 1 overdrive ratio making even 4.11 gears great on the street. The following information is what I've found out over time and what I encountered installing it in a 1979 Z28 Camaro.

The 700R4, 4L60, and 4L60E have the same external dimensions and case. The 4L60E is the electronic controlled version of the 700R4 / 4L60. The transmission has the following dimensions and gear ratios

Case to ext Housing Overall Length Bellhousing to mount

23 3/8" 30 3/4" 22 3/8"

Transmission 1st Gear 2nd Gear 3rd Gear 4th Gear OD

Turbo 350 2.52 1.52 1 N/A

Turbo 400 2.48 1.48 1 N/A

2004R 2.74 1.57 1 0.67

700R4 /4L60 3.06 1.63 1 0.7

4L80E 2.48 1.48 1 0.75

I recommend to get an 1987 or later 700R4. 86' and older 700's have a reputation for problems. If you stick with 87' and newer the tranny will have a 30 spline input shaft and a 27 spline output shaft. This allowed me to re-use my drive shaft yoke from the Turbo 350.

The mounting pad on the 700R4 uses the typical TH350 / manual trans 3.75 inch bolt spacing. The bolts going into the 700R4 are M10x1.5x (length required). Metric torque converter bolts are also required to bolt the converter to the flexplate, GM (PN 1261968).

The 700R4 uses a lockup converter. I love my lockup. The person I spoke to at Art Carr doesn't recommend using a lockup converter, I guess that's why I bought a TCI 3000 rpm stall lockup converter. The lockup converter allows me to have a high stall and cruise on the highway. With 3.73 rear gear and a 28" tire 2500 rpm is about 80 m.p.h.. If I didn't have a lockup converter I would be constantly slipping with my converter on the highway. I don't use the lockup in any other gear than overdrive and I disengage the lockup under full throttle. It's great you can have your cake and eat it too, high stall for good launch, lock up the converter on the highway and cruise home.

700R4 wiring diagram

I control the lockup on the converter manually. The wiring diagram shown is how I wired my car. I got the toggle switch from the junk yard out of an older Nissan Maxima, it's lighted and says O/D on it. It's simple I push the switch and the tranny locks the converter. In a braking situation the brake switch disengages the converter for me. Sometimes I forget the converter is locked up and I'll bog the motor...ooooops press the button to disengage the converter. I've never used one of the kits for controlling the lockup but I'm the type who likes to control when I want the converter to lock. I hate it when a tranny keeps going in and out of lockup. If this is not for you all of the major tranny companies offer a lockup kit for the 700R4, B&M, TCI, Art Carr, etc.

For mounting the 700R4 the cross member had to be slid back approximately 3". I was able to re-use my TH350 cross member and just drill extra holes in the front sub frame. I used the orginal back bolts as the front bolts for the 700R4 and drilled the sub frame to match the crossmember back bolts. The drive shaft also had to be shortened by approximately 3".

I installed a B&M Megashifter which allows for 4 forward gears. The one I put in is the unit made for the Camaro center console. The shifter is a little hard, requires a lot of force, but it's nice. I love the ratchet action.

The stock 700R4 has low shift points because it typically came with a TPI motor that runs out of steam at 4500 rpm. My motor turns on at 3500 rpm and I like to shift at 7000 rpm for first to second and 6500 rpm for second to third. The one bad thing about the 700R4 is the big gear drop between the 1-2 shift. So I hold first longer to put the motor in more of a sweet spot for second. The point I'm trying to make is , buy a kit from B&M which you can adjust the shift points. It's for the governor and it's different weights and springs, unfortunately you have to experiment to figure out the shift points. For mine I have to pull the tranny out to get at the governor, Oh well.

The only other modification that I had to do is to cut off a section of the case to clear my headers. The piece I removed is on the passenger side.

The 700R4 transmission in the Camaro recently blew up. With my luck the tranny let go on the highway around midnight with no one around. I had to walk a few miles to the nearest phone to call for help. The tranny let go when I was accelerating up to highway speed from the on ramp. The funny thing is that night I went to the shop to examine the drive line because I heard a SNAP when I hit the nitrous racing someone. I was planning on going to the track the next day and I wanted to make sure everything was OK. Needless to say I didn't see anything that would lead me to believe anything was going to let go. Well it did in a big way.

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