CamDriver

hi i have a t-56 and going to change to a 700r4... can any of you tell me if the trans crossmembers are different or will it work with the 700r4 any other info you can think of will be helpfull also feel free thanks jeff

JakeRobb

Some of these details vary depending on what year your car is, but since you said T56, I'm assuming you have a 4th gen (93-02). The more details you provide, the more helpful we can be.

Going on my 4th gen assumption: The crossmembers are different. I believe the PCM is also different (because the PCM for a manual trans car doesn't have the circuitry to control shifts), but if you're going with a 700R4 (from a 93 or earlier) instead of a 4L60E, you wouldn't need the circuitry anyway. You'll need to remove the clutch pedal assembly and master/slave cylinder, and cover up the hole in the floor where the clutch was. The bellhousing is different (which only matters if your new trans doesn't come with one). Driveshaft length is different. The rear end gearing on a manual car is shorter than on an auto car. You'll need a different console to accommodate the shifter (which is also different, and you'll need a linkage to go with it). There may be additional differences; those are just the ones I know of. 4th gen torque arms mount to the transmission tailshaft; I don't think the torque arms themselves are different, but that'd be something to confirm.

You'll want to disable CAGS (aka "skip shift") in the PCM or make/get one of those disabler things so that you don't get a Service Engine Soon light.

Suffice it to say that there's an awful lot of work involved in the conversion. It's not impossible or anything, and lots of people have done it, but there are plenty of guys out there that want to go the other direction. Why not find one of them and trade?

Injuneer

Same physical PCM. Just the programming is different. What year is the car?

You will need the cross-member from an A4 (4L60/4L60E) car. Not the same as the T56 cross-member.

12SCNDZ

You will also need a '93 F-Body throttle body that has a pivot for a TV cable, a '93 F-Body specific TV cable and a '93 TV cable bracket.

Frank

Injuneer

And, driveshaft lenght is going to be the same unless you find some oddball 700R4. You will need a flex-plate. The year of the vehicle will determine what has to be done to drive the speedometer/odometer. The PCM needs to be programmed to match the VSS pulse/mile output. Torque arm is the same, but the front mounting bracket is transmission specific.

CamDriver

thanks guys huge help!!! i did forget some key info.. its a 95 camaro.. i have a umi torque arm (that dont mount to the trans) i am going with a 700r4 with loc up converter because its a daily driver.... thanks a ton guys

Injuneer

What advantage does the 700R4 offer over an electronically shifted 4L60E?

12SCNDZ

Fred has a good point. A 4L60E out of a '95 would be an easier swap. The cable and bracket for the TV cable I mentioned aren't available through GM anymore, so you would have to find them in a yard somewhere, unless someone is finally making them aftermarket.

Frank

Injuneer

Frank - aren't there some internal upgrades in the 4L60/4L60E compared to the earlier 700R4?

12SCNDZ

Most certainly over the early 700R4. the early 700s had input roller clutches instead of sprags. They were a weaker 27 spline input shaft, old style narrow rear sprag, leaky drums, as well as a few other things. The 700 did have a stronger output shaft, and the 3rd design 700R4 input sprag was better than the stock 4L60E.
I'm just looking at things from an adaptability perspective. The 4th gens had 700's (4L60s) in '93, but went to a 4L60E in '94. It will be easier to find and work with 4L60E stuff. If swapping in a 700, you also have to figure out how you're going to run your lock up wiring. Finding an automatic car in a yard to use for donor parts would be the easiest way to go.

Frank