The terms are often used interchangeable, but there is a key difference between a transaxle and a transmission. Rear and mid-engine Porsche have a transaxle.
Our transaxle isn’t original to the car, but is number range appropriate. A bit dirty from storage but California Motorsports (CMS), where we plan to take it for evaluation, say they’ve seen worse.
Lisa spent the better part of two days cleaning and degreasing the thing. Per CMS instruction, we covered the vent and didn’t power wash it. What worked quite well was a combination of three things:
- Extreme Simple Green Aircraft & Precision Cleaner: It can be used on aluminum, carbon fiber, high tech alloys, structural metals, etc. Given so much of the 914-6 metal is magnesium and other alloys, this is reassuring. Particularly after Oil Eater destroyed my magnesium rocker stands.
- Holikme drill brush: The black stiff material works quite well with a cordless drill. Though you still have to be careful not to gouge the metal.
- Script Scraper: Great for scraping out the compacted on stuff in tight places. I was surprised how popular this was with Lisa and my dad’s wife. They ended up stealing mine and buying more.
Do You Prefer Tail or Side
Trying to distinguish the 914-6 transaxle from 911 and 914-4 cars was a bit of a challenge for me. Porsche leveraged the tried-and-true 901 transaxle from the 911 when developing the 914. Note that it was the second iteration of the 901, commonly known as the “911 transaxle”, which is all-magnesium cast 5-speed gearbox (as opposed to previous aluminum housing). Given that the 914 had a mid-engine config, compared to the rear engine 911, it meant flipping the transaxle around. This resulted in a shift selector mechanism much farther away from the shift knob than it had been in the 911. This resulted in considerably more sloppy and slow shifts. From that layout, two variations came to be in the 914 cars. There are side shifters and tail shifters. Little knobs and linkages seem to make the difference.To further confuse things, you can’t just look at the casting number on the housing, as some different application part numbers have shared casting numbers.
914 Transaxle Flavors
- 914 cars -72 were tail shift. This includes 914-6.
- Since 914-6 were only made 1970-72, all 914-6 are tail shift
- 914-6 tail shift is different than -4 version. 914-6 tail-shifter linkage is considered superior to the -4, mostly due to it not having to go around the sump of the motor.
- The most humorous description I’ve read on tail shift is: Tail shift = Like shifting a stick in a jar of mayonnaise.
- 914 cars 73- were side shift (914/12 designator)
- Side shifters are generally considered easier and more precise to shift. Many people convert tail shifters to side shifters.
OK. So they were different and one seems preferable. What makes them different and how can you tell them apart? The easiest way is to look at the model / serial number on the case. But that assumes you can see it, and that the transaxle hasn’t been modified. Per Porsche factory parts catalog, 914-6 would have:
- Model: 914/01 5-speed manual, or 914/05 4-speed Sportomatic
- Serial Numbers: 75X 0001 >> 5-speed manual (where X could be 0, 1, or 2), 780 0001 or 761 0001 >> 4-speed Sportomatic
I have found it surprisingly difficult to find a visual side-by-side comparison of side and tail shifters. A couple of images from the factory workshop manual help. The 914-6 distinguishing feature is the ball-joint bell crank.
That later 914/12 side shift transmission is basically the same as the previous version. The key change is the side-mounted support with shift linkages, modified shift rods, and modified rear cover (shift lever shaft is no longer in the rear cover).
