Chapter 14: Into Overdrive


As mentioned previously, I had scored a “1971 stock 3 speed, transfer case and overdrive” assembly from a barn 6 months ago for Homer. It had not gone as planned as I didn’t realize that there were more than one 3 speed transmissions available for my year CJ. The overdrive would not mount to my CJ drivetrain. And the newly acquired drivetrain needed a special bellhousing to mount to my engine. Plus, it was the weaker option.

So not the most useful purchase. That’s what I get for not researching beforehand. I can probably get more out of it than I paid if I just cleaned the decades of dirt and grease off of it.

Seemingly unrelated, my wife found a piece of equipment for work that she always wanted, but it was in Denver, over a day of driving away. Well, since I was heading there anyway, time to hit up Craigslist for any Jeep goodies. I quickly eye a rare 10 spline overdrive. Score! This is what will fit Homer. Call the guy up and schedule a meet.  A quick 3 day round trip to Denver and back to the garage with something that should work. Oh, and the equipment my wife wanted.

I compare the two overdrive units and swap a few minor pieces to make a better one and fit it up. It actually takes less than an hour and it is bolted on. Oh yeah, this is going quick. Then the hour wait for the permatex to set up and torque it up. Start filling with gear oil. Finish the one open bottle, finish the second open bottle…crap. No third bottle. Well, that will have to wait. But at least I can put on the shifter.

Or not.

The overdrive end hooks up easy enough with a pin, but the bracket to the transmission doesn’t look right. I compare it to the other one I got off the 6 spline overdrive and the wrong transmission. They are indentical. So, now I have two overdrive shifters that do not fit my specific vehicle. But they do fit the useless transmission on my floor. Great.

I attempt to make a bracket out of a piece of angle iron I have around. It fits to the trans great, but the shifter rod hits both the transfer case shifting tower and/or the transmission case. Befuddled, I search the internet and find that I need a unique shifter and not just different transmission bracket. I decide to punt and just throw some money at problem. Seeing as it is a unique piece and I don’t want to butcher the original, stock-for-some-other-jeep shifter assembly, I consider it a deal.

I decide to install a small heater while waiting for the shifter to show up. What better accessory is there to install in August in the desert? The highs are at least below 110F.

I decide on the smaller of the heaters available through Summit Racing. The install was simple enough. Found a spot under the center of the dash, drilled four holes to mount. Another two big holes on the right center of the firewall for the bulkhead fittings. Plumb it to the heater hoses that were previously looped from water pump to intake manifold. Well, actually I replace all the old hoses as they used one size too big and just clamped it down. Install the switch in a previous hole in the dash and attach to positive battery voltage. Boom. Done.

Well, on the battery connection, I decide to throw a small bladed fuse holder on the side of wooden glove box, and special homemade design by some previous owner. Eventually, I will move more electrical connections through the fuse block as they are all currently using inline fuses. I will do that when I decide to replace the ancient wiring.

Now to fire it up to see if it works or if a hose will let loose and coat me with heated coolant. I’m getting excited. I had been used to needing to reprime the carb by dumping some gas down it and firing it up. After it sits for a couple of weeks the carb bowl is dry. This time it doesn’t work the first time. Or the fifth. I finally disconnect the fuel line at the filter, which is installed between the pump and the carb. I get a little fuel to the filter and try again. Filter is dry again. Huh.

Welp, time to pack it in for the night.

A couple weeks pass as I wait for the new shifter to show up and I take a trip out of town. When I get back, I struggle with the shipping company’s game of hide-the-package, but eventually I get my hands on the goods.

I throw the new linkage on. It’s aftermarket, so of course it doesn’t fit. Sigh. The main linkage was a fairly flat piece of flat stock. A quick use of the vice and all my pent up anger towards a certain shipping company, and the linkage no longer hits the transmission or the transfer case shifter. In fact, it nicely zags from back to front.

However, the shifter rod itself hits the bell housing bolt when you pull it back. I trim the corner off the inside of the bottom of the shifter lever and still have to use a couple washers to shim it out for clearance. After that fix, I can’t quite shift out of overdrive as the shift knob smacks the dash. And I can’t quite shift into overdrive as it hits the transfercase shifter.

This is not ideal.

Hard Contact

An hour spent with the vice, a torch, and a few of four letter words (the torch makes everything hot) is rewarding. I now have a shifter that doesn’t hit the dash, the transmission shifter or the transfercase shifter. Of course, I still can’t install the floor pans until I cut a new slot but that is trivial. A little 4″ cutoff wheel and a few sparks later and done. I button it all back up.

Back to the starting issue. Give it a crank and it still isn’t sucking fuel into the filter. I drop a line straight from the pump into a tank of gas, just in case it can’t pull it all the way from the tank. Still nothing. Eventually, I prime both the mechanical pump and the carb at the same time and he fires right up. Purrs like a cat. He just doesn’t like sitting for long periods of time, I guess. I place an order for a check valve to put in the gas line.

Time for a test drive.

First off, Homer is lumping around on tires that sat in one place for too long at a low pressure. Next, I hear a lot of banging going on, but all of it sounds exterior to any drivetrain components. I should mention that these noises are not totally abnormal, just a little louder than usual. I get up into 2nd gear and shift the overdrive. The revs jump higher as I instantly realize that I had the shift pattern backwards. Hey, it was a 50/50 chance. I just assumed pulling back on the lever would put it into overdrive. Nope.

No biggie, I push the lever back up and the engine revs again. This time it is due to being in some sort of neutral. Moving the transmission and overdrive levers do nothing to provide any gears. Did I remember the two cotter pins holding the overdrive shift linkage in? Between that and the banging, I decide to pull over at the next wide spot in the shoulder. I swear I put the cotter pins in.

I look down and notice that the left transfer case shifter isn’t where it should be. Somehow, I managed to shift both the overdrive and the left transfer case shifters forward in one motion. Baffled, I put the transfer case back into gear and it moves again.

I pull over in a better spot to check it all out. Everything seems to be holding and no wheels are coming loose. I do notice that when I installed the main floor panel over the transmission, I must have had it shifted to the left as it just barely touches the overdrive shift lever. However, when running, this causes a lot of noise.

I drive down for gas and lunch and back to the house. The engine very much appreciates the overdrive. It shifts smoothly into and out of overdrive. The overdrive shift knob does tend to lightly tap the main shifter when in 2nd gear overdrive. Bah! I can live with that until I have a chance to bend the shifter a bit more.

I cut a tiny bit of the floor pan off to clearance the shifter. I love Jeeps. Did I take the floor pan out? No. Did I just drag over the airline and use a 4″ cutoff wheel to trim the floor pan? Yes. Perfect.

With that, the overdrive install is complete. Sure, I think the main linkage is hitting the transmission case while bouncing down the road. And the shifter could use a tweak, but I’ll fix those issues later.

Suck it Millennials!

The heater is close to working. I need to purge the air filter from the heater in the dash, but it’s getting close to my start time at work. I hope it makes the commute!

Well, it made it to work. And onto a few adventures. Including a windshield down drive through Zion National Park. Epic.

Leave a Reply