Shift Linkage

With the engine in place and the firewall under construction I decided to take a closer look at the issue of the shift linkage. #3854 came with very few parts. As far as the shifter was concerned there was next to nothing there. When I priced out all the parts I needed it came up to over $1,200 for what I needed to be able to change gears on the ZF. That was a price I hadn't anticipated.

So I did a little digging. I came across lots of chat on various boards about replacing the shaft system with a cable mechanism. Here's the link to the system some used to convert their Panteras.

http://www.malinmotors.com/products/p_cableKit/p_cableKit.html

Most of the chatter was positive, but like most big modifications it went about 50/50 pro vs con. Plus this system is just about as costly to purchase as it would have been to locate and purchase original or near original parts for the Pantera.

Then I found a discussion on replacing the u-joints and was lead to this link.
http://www.flamingriver.com/index.php/products/c0005/s0004/FR1761
Apparently Flint River makes some very good u-joints at a good price. The ones linked to above were about $80 each, give or take depending where you got them.

The joints linked to above were the correct size and have the 36 splines that were part of the Pantera shift linkage design.  Problem for me was that the original shafts for the Pantera are all way too expensive, in my humble opinion. My brain started thinking, "Is there some way to use Flint River u-joints and make my own shafts?

Of course I don't have the tooling or expertise to make shafts with 36 splines on them. But what if I got creative and eliminated the splines all together? I did a bunch of research on the u-joints and found that I can purchase a 3/4" diameter u-joint from Flint River for a reasonable $67 each. With that knowledge I went to my local metal shop and found a 10' length of 3/4" dia, 0.120 wall steel pipe for a mind blowing $15! Surely I could make this shift linkage myself.

I decided to take the plunge and order the u-joints. Here's what I got. I found P/N FR2630 at SummitRacing.com for $65 a piece. These are 3/4" x 3/4" forged needle bearing steering u-joints made by Flaming River. They come in a flat black finish. Here's a picture of one of them.

They are weldable and have a threaded hole for mounting to whatever shaft you want to use. They are smooth (no splines) so you have to do something to hold them to the shaft. Once I received the order from Summit Racing I couldn't wait to get going.

The first problem I decided to tackle was how to attach the smooth bore of the u-joint above to the 14mm, 36 spline shaft coming from the shifter box inside the car. Here's the cool part about using tubing for the shaft - the inside bore of the 3/4" dia, 0.120 wall shaft is only about 0.015 smaller than the 36 spline shaft that I want to attach to the u-joint above. I decided to cut a short, 1.5" length of my tubing and do a little rework to make the tubing fit over the shifter shaft. Then the u-joint would slip over the tubing. Here's a picture showing it all laid out the way I want it to go.

The piece on the left is the shifter shaft from the shift box inside the car. See the splines on the shaft? The silver piece in the middle is a short piece of the 3/4" dia tubing I'm using as my shift shafts. This piece will act as a sleeve to allow the 3/4" dia u-joint on the right to slip up over the splines on the original shifter piece on the left. You can see the hole in the side of the u-joint in the picture above. This is a threaded hole where a lock bolt can go in to hold the u-joint in place.

Now, what to do about the fact that the tubing diameter is some 0.15" smaller than the splined shaft from the Pantera? Since I couldn't find a drill bit the right size to open the tubing up I decided to grind down the splines. Definitely a point of no return decision but why not go for it?

After a little grinding the tubing fit over the shaft from the Pantera with a good tight snug fit. I then did a little clean up grinding of the outside diameter of the tubing to take a few thousands off so that the u-joint would fit over the tubing easily as well. Without grinding the OD of the tubing the fit would have been more of a press fit scenario. I wanted to be able to easily remove the u-joint if something went awry later on.

I then decided exactly where I wanted the u-joint to sit with regards to the shaft from the Pantera and made a mark in the middle of the mounting hole on the u-joint. I drilled a 5/16 hold through the tubing, through the shaft from the Pantera and made a hole on the opposite side of the u-joint (in a separate drilling process) to allow a bolt to be fed through the assembly and be bottomed out in the threaded hole that came in the Flint River u-joint.

Here's a few shots of the steps described above. This first picture shows the splines ground down to allow tubing to fit over the shaft.

This shot shows you the hole I drilled through the tubing through the original splined Pantera shaft.

Here's a picture showing the hole I drilled in the other side of the u-joint to allow the retaining bolt to go through the entire assembly. You have to be careful not to drill out the threads that came in the u-joint. What I did to drill this hole was to put the entire assembly together then use an under sized drill bit to go through the threaded hole on the u-joint through the tubing and splined shaft and let it hit the other side of the u-joint (where I want the hole seen below to be). I then tapped the drill bit with a hammer to make a mark where I wanted the hole to be. On the drill press I used a very small bit to drill a pilot hole passing through the threaded hole. With the pilot hole through the other side I turned the u-joint over and drilled it out to the 5/16" final size.

Finally, here's what it looks like assembled.

Of course I won't be using a carriage bolt to hold the assembly together - this was all I had at the moment. I was amazed at how secure the connection was with this method. Best yet I can still take it all apart when I need to.

Next I needed to determine the exact length of rod I need to go from the Ujoint coming from the shifter box above to the next Ujoint towards the back of the engine. To make this determination accurately I needed to fab up the support piece that mounts on the frame on the left side of the engine. To make this piece I found the following parts in my junk pile.

I need some threaded rod to mount the support to the Pantera frame. I used a 1/2" bolt and welded it to the ring above to come up with the following.

I then drilled out a dimple in the green poly bushing to allow the thumb screw to help hold it in place. It is a pretty tight fit so I don't think it is going to go anywhere. I did have to do a little honing out of the ID of the poly bushing to make it slide fit on the 3/4 shaft that will pass through it. Here's a shot of the assembly going together.

Here's the finished rod support.

With the support made, I cut a piece of 1/4" steel plate and drilled out a clearance hole for the 1/2" bolt of the upright to fit through. I also drilled out a hole to mount the plate on the frame of the Pantera. It had to be shifted about two inches toward the center of the engine to give the proper clearance for the shaft to fit under the Coyote engine. You can see the final assembly shot a little ways down this post.

With the support in place I could insert a longer than needed section of 3/4 pipe from the back of the Ujoint in the shifter box, through the support so the rod would stick out past the bell housing. Once I took a careful look at the angles that would result from this point back to the shifter mechanism on the ZF transaxel, I marked how long I wanted the rod and attached the Ujoint to it. Here's a shot of this end of the rod assembly.

Again, the mounting bolt was just something I had laying around. Notice the amount that I cut off the bell housing to make room for the shift linkage. Here's a shot showing how much was interfering with the linkage.

I then made the mounting piece that goes on the shaft protruding from the shift mechanism on the ZF. The shaft is a 5/8" dia. I took a piece of 5/8" ID tubing and worked on taking a small amount out of the ID to allow the tubing to fit snugly over the ZF shifting shaft. I drilled a hole in the tubing to match the hold on the shaft coming out of the shift mechanism.

Next I took a piece of threaded rod the same OD of the 5/8" tubine I worked on above and pressed it into one end of the tubing. I welded that in place. I then welded a nut that fit the threaded rod in place to give me something to grab onto to tighten up the adjustable portion of the shaft I made next. Here's a shot of the finished product. It was basically a matter of piecing together the necessary parts to take up the space from the back of the rod coming from the shift box to the piece I made to attach to the ZF.

Here's shots of the rest of the linkage all in place. Best part of this project is that it works! I am able to shift in all gears. I know that I'll have to make minor adjustments but that won't happen until the car is running.

Here's a good shot of the mounting plate and support piece for the long rod coming from the back of the shifter box in the passenger compartment.