Some of you might have thought I'd dropped off the face of the earth the past few days. I've been a busy fellow. I've begun the process of swapping my TH400 transmission for the electronic 4L80e overdrive transmission. I've been taking pictures so here's a build thread for you.
The first thing I'd like to say is that this is in no way a bolt it in and go operation. There is going to be some fabrication involved and I suspect Bryan and I will have to do some creative thinking before it's done. I'd also like to thank my brother in law and our club sponsor, Bryan Blocker of Blocker's Performance and Restoration, for helping me with this project. (Like he had a choice, he's family after all. LOL.)
The first order of business is to remove the old TH400. Bryan Blocker and I have done this so many times that it takes less than 30 minutes with us working together.
The next step is removing the flex plate. It has to come off to mount the transmission adapter plate since the modern electronic transmission do not have a BOP bolt pattern. This aluminum Reactor flexplate I was using won't work with the new setup due to its thickness so it will be replaced with an stock flexplate.
Since we're using an adapter plate to mount the transmission the old locating dowels have to be removed and new, longer dowels installed. The part number is Moroso 37932. The first dowel come out with vice grips and a twist. The second one wouldn't come out despite the use of heavy explosives. I ended up drilling it to get it out.
With the new dowels in place the adapter plate from TCI bolted right in, no problems at all. That part is TCI 230001. Be sure to read the instruction on which way the plate faces and how to measure the pull on the transmission. You MUST use the supplied washers.
The next item was to drill a hole in the transmission tunnel to route the wiring harness. The main connector has a 1 5/8 inch diameter so the hole has to be that big. The wires coming through include the main connector, the transmission input speed sensor (TISS), the transmission output speed sensor (TOSS), the throttle position sensor (TPS) and a ground wire that needs a direct connection to the (-) pole of the battery. I'm bringing all this through the tunnel as I'm placing the transmission control unit (TCU) under the center console.
The throttle position sensor seen here is critical to this install. It helps the transmission control unit to determine where shift points should be and when to lock up the over drive. I fabricated a bracked on the rear of my Quadrajet mount and set it up to use a pull wire via the throttle linkage on the driver's side of the carburetor.
Here's the stock flex plate installed along with a Trans Dapt torque converter pilot bushing we were led to believe we needed. Maybe some other folks do need it. We did not. When we bolted up the transmission with it in place it jammed the converter snout so tightly we couldn't turn the converter by hand. We pulled it all apart, threw the damned thing aside and it all came togther like a dream. For those who might need it, Summit Racing sells it and the part number is TD-055.
You might be able to pull this swap off in the home garage but at my age, it ain't happening. The use of a lift and the transmission jack are the only thing that makes this job doable. Again, a big thank you to BPR.
The complaints against the 4L80e is that it's huge, heavy and sucks up horsepower like a black hole. In a side by side photo you can see that the 80e is much larger. We didn't weigh them but others have and the 80e outweighs the TH400 next to it by 45 pounds, sans converter. Most of those complaining of the weight will admit that the bulk of the xtra weight is in the stock converter, a huge, heavy duty piece for towing and big trucks. I'm using a small, performance converter so the actual weight gain for me is going to be very close to that 45 pound mark. As for huge, cut off the two transfer "ears" on each side of the case and it will fit your F-body's tunnel with no modifications.
Here's a shot of the transmission going in with the smaller, performance converter in place. I sourced that through Jake Shoemake out of Sanger, Texas. He has a strong following with the Buick performance guys and a lot of experience with 4L80e builds.
Remember my admonition to read the instructions on the TCI transmission adapter? It includes using these hardened washers when you bolt down the converter. You have to measure the pull back from the transmission towards the flex plate. If it's less than 1/8 inch you'll be OK. Oh, don't forget you'll need metric torque converter bolts. They are 10mm x 1.5 thread.
This next shot is a little hard to see but I'm trying to show you the -6AN fittings I'm using for cooler lines and the flexible cooler lines. You can use hard lines but the bigger transmission makes it a VERY tight fit in there. I found that using the 3/8 NPT to -6AN fittings made routing this stuff a lot easier.
With the transmission bolted in, converter on and cooler lines routed we moved to the electrical connections. It's all plug and play here. They're all weather pack connections and can only go on one way.
Now we get into the fun part. No one builds a cross member for this swap It's fabrication time. With the cross member from my TH400 flipped around backwards it appears we can reuse it with some cutting and welding. I grabbed a grease pencil and started some sketching.
No matter what we did on the cross member, that mounting tab has to be on the other side so I used a cut off wheel to lop it off. This is where we stop for now. The drive shaft shop had not returned our cut down drive shaft yet. Without it we can't set the pinion angle and determine the exact mount location. And for those who are already asking, the drive shaft had to be shortened by 3.25 inches. Also, the TH400 yoke with its 32 spline count will work with the 2 wheel drive version output shaft on the 4L80e.
To be continued...