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1967 Chevrolet Chevelle SS - TCI 4L80E Installation

Kickin’ It Into Overdrive - We give our AMD Chevelle a couple of extra gears and a lot more drivetrain strength, thanks to a TCI 4L80E.

Patrick Hill Feb 7, 2014
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Back in the August '13 issue of Super Chevy, we followed the build of a TCI 4L80E transmission that would ultimately end up under our AMD '67 Chevelle long-term project car. After rebuilding the 402 big-block (Sept., Oct., Nov., Dec. '13, and Jan. '14) we got the car buttoned back up and bolted to our chassis dyno for some baseline runs and tuning, before hitting the dragstrip. After two runs on our Dynojet, a big puddle of ATF spelled an end to our baseline testing, due to a massive fracture in the car's existing (non-original) Powerglide case.

So, skipping our drag test, we went straight into installing our 4L80E. A brief recap, the 4L80E heavy duty overdrive trans first debuted in 1991, as a replacement for the TH400 in HD applications that needed an overdrive gear for better fuel economy. It combined several of the existing parts from the rock solid TH400, and quickly proved to be a beast capable of handling high horsepower and extreme duty in a variety of applications. Today, it is the first choice for those wanting an OD trans that will take high torque, high horsepower, and plenty of abuse without puking its guts out.

Parts List

4L80E – part no. 271150
Deep Pan – part no. 278000
10-inch billet cover converter 3000 stall – part no. 242948
Flexplate 168 tooth – part no. 399273
Trans cooler – part no. 824104
Trans Mount – part no. 952500
Break In ATF – part no. 15900
4L80E Filter Kit – part no. 278500
TCI Synthetic ATF – part no. 950655
Dipstick – part no. 743805
4L60E/4L80E Remote TPS w/bracket – part no. 377400
EZ-TCU Trans Controller – part no. 302820
Speedo Control Unit – part no. 377300
5/8 Speedo Cable – part no. 377301
Carb Adapter Bracket for Holley – part no. 376705
TV Cable Corrector for Holley – part no. 376715
Output Sensor (Autozone) – part no. SU1138

Follow along as we get this bad boy installed in our '67.


1. After removing the Powerglide, we got a good look at the case fracture. It went from the pan flange on the driver's side, all the way to the pan flange on the passenger side. This case is now scrap.


2. Our new TCI 4L80E features TCI's strengthened internals and 2.75 first gear (1.48 second, 1.00 third, .75 overdrive, and 2.07 reverse) and a 3,000 stall 10-inch converter that will work perfectly with our 3.73 rear and solid-lifter cam big-block. With TCI's deep aluminum pan, our 4L80E will never starve for fluid.


3. We also installed TCI's 168-tooth SFI rated flexplate. Before you start emailing us, we did flip the flexplate around to the correct orientation (SFI stickers facing towards the block) before attaching the transmission.


4. Here's our trans controller, TCI's EZ-TCU. Featuring the same adaptive technology and easy programming as FAST's EZ-EFI system, once the brain is plugged in, all you have to do is set some basic parameters, then let the computer handle the rest.


5. Here's the harness. Everything's labeled, so there are no mysteries where the wiring goes. It looks daunting at first, but installing it was a breeze.


6. Before installing the trans, we needed to hit the parts store and get a pair of stock output sensors to plug into the trans case (part no. SU1138 at your local Autozone). Even though we'll only be using the rear output sensor to send a signal to the computer, the front sensor is still necessary to plug the hole in the case.


7. When we raised the trans up into the tunnel, we found the output sensor was hitting the trans hump. This is normal for a 4L80 swap into an early car. No worries: We picked up our Eastwood body hammer and massaged the tunnel to gives us a nook so the sensor would clear.


8. Because the 4L80 is a truck transmission, its bellhousing is much beefier than a car trans. Because of this, we ran into a clearance problem on the passenger side with the exhaust. Again, not a problem. We used a sawzall to cut away the offending ear (with no structural compromise of the transmission case) and it slipped by the exhaust pipe with no problem.


9. With the transmission in place, we bolted on our new polyurethane transmission mount.


10. Because the 4L80 is much longer than the Powerglide, we knew the stock driveshaft would have to be replaced. We measured from the seal on the tailshaft housing to the pinion yoke on the rear …


11. … and sent our measurement to the Driveshaft Shop to have a new aluminum shaft cut to our needed length. The Driveshaft Shop unit is made from 60601-T6 DOM aluminum, with solid Spicer joints, and balanced on one of the only high-speed balancers in the world.


12. On top is our old output yoke, on the bottom the 4L80E yoke. Just by size alone you can see the 4L80 unit is much beefier than the Powerglide's.


13.To secure the 4L80, the factory crossmember had to be modified. We cut the tube on each side, then bolted them down, measured, and welded in pieces of plate steel to connect everything back together. This will be replaced later with an aftermarket crossmember, like the one available from Original Parts Group, part no. CH28439. It retails for $279.95.


14. With everything mounted below, we started running the control harness for the EZ-TCU system. Greg Lovell from Antivenom EFI came over to give us a hand.


15. To better conceal things in our otherwise stock engine compartment, Greg showed us his trick for covering the exposed wires, using electrical tape, that would mimic the factory harness wrapping.


16. To hook the new trans to our column shifter, we got a shift arm connection kit from Shiftworks, part no. KK02. We also got a new lens decal for the shift indicator as well. First to be mounted is this bracket on the transmission, on the shift actuator.


17. Back up top, we mounted TCI's TV Cable corrector bracket. Even though we aren't running a TV cable, we still needed the bracket to mount the TPS sending unit cable that hooks onto the carb linkage.


18. Part of the kit includes this adapter bracket that hooks to the linkage on the carb. Both our stock throttle rod and the TPS sending unit cable will hook to this.


19. Next up was mounting the TPS sending unit, after we plugged it into the harness. After connecting the cable to the carb linkage, we mounted it on the back side of the inner fender.


20. Because the 4L80E is fully electronic, it has no provisions for a mechanical speedo cable. TCI's speedo control unit plugs right into the EZ-TCU harness, and receives the signal from the output sensor on the trans. The unit in turn drives a mechanical speedo cable you connect to the car's factory speedometer.


21. Without taking the dash apart, we were able to get underneath it, disconnect the factory cable, and install the shorter one from TCI that hooks into the control unit.


22. Quick tip to make installing the cable on the speedo end easier. Take a rubber band and wrap it several times around the cable shaft, to keep the mounting cup from sliding down the cable.


23. From there we hooked in the RPM signal unit to the distributor, then secured it on the firewall.


24. With the harness plugged in to all the sensors, we plugged it into the EZ-TCU brain, and mounted it on the front of the inner fender, hidden away from plain sight and also protected from water splash or heat from the engine. This gives our trans install a much stealthier look too.


25. For constant power to the trans controller, we ran the power and ground wire under the top of the radiator support, over to the battery. The instructions say to hook the red wire directly to the battery for constant power, but we found it easier to hook into this fusible link in front of the battery, that has key off power running to it. We ran the ground to the backside of the ground wire coming off the negative battery cable, effectively hiding both wires but hooking them up properly.


26. We mounted the speedo control box here on the inner fender, just below the master cylinder.


27. Our adapter rod for the column shifter is longer than the stock one. This requires some test fitting first, then trimming and bending of the rod to get everything right.


28. The EZ-TCU also has a key on power wire that needs to be hooked in. We used this open plug on the factory fuse block and plugged the wire right in.


29. After hooking our shifter rod into the column linkage, we ran it down to the trans and measured what we had to cut off.


30. The rod also required a little bending so it wouldn't bind during operation. The arm on our two-post lift made that an easy job.


31. After using a cutoff wheel to trim the rod, we installed the end and hooked it into the bracket on the trans. With the shifter in park, we moved the gear selector on the trans to park, clocked the linkage bracket to hook up with the rod, then tightened everything up. After that, we had all seven shift points with our factory column shifter.


32. Part of our kit from TCI was an external trans cooler. For maximum cooling, we mounted it in tandem with the factory cooler in the radiator, to keep our TCI synthetic ATF as cool as possible during hard use.


33. The next step was to turn the key on, hook up the EZ-TCU programmer, and program in the basic settings for the trans controller. If you don't know your tire diameter, it gives you the option of what size tire you're running. You will need to know your rear gear also.


34. Last thing to do is fill up the trans with TCI's Break-In synthetic ATF. After a 30 minute drive under light driving loads, we pulled back in, dumped the fluid, changed the filter, and refilled with TCI's regular synthetic ATF.


35. And there you have it. We went from two gears to four, have a cruise-friendly overdrive to mate with our 3.73 rear gear, and have three forward gears tough enough to take just about any punishment we can dole out at the dragstrip or autocross.


Ashland, MS 38603
Eastwood Company
Pottstown, PA 19464
Auto Metal Direct
Buford, GA 30518
Driveshaft Shop
Salisbury, NC 28147



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