924Board.org

[SubyDrew]

Recently, I decided to swap out the transmission in my ’81 924. What follows is a brief accounting of some things that I wish I had known before starting this project. I hope other novices can learn from my mistakes.

I’m what you might call a handy amateur. I’m willing to tackle most anything on a car that I don’t have to rely on to drive to work, but I’m usually attempting the project for the first time.

I found an ’85 944 transmission on eBay for about $350, delivered. It seemed better than trying to rebuild my crunchy box. A buddy that I help with his Alfa agreed to help me and loan his garage for a weekend. And only a weekend, seems fair as I was told that the job should take about four hours. It took me about fourteen hours – with help. I could probably do it again in about six. Be sure to have all your tools before you start.

First things first, jack the car up. I have a jack that goes to about 20 inches. With the car on stands at full height, there was just enough room to get the transmission out. Use a good set of heavy stands, the 6 ton stands were much more stable at this height than the 2.5 ton stands that I used at the front of the car. The Hayne’s manual was useful, but some steps are not required, while others need a bit more information.

Chapter 7, section 2, item 6. My shifter was tight, and did not want to come out. I did not remove the shifter, and was fine.

7:2:7 I found 4 to 6 inches of clearance adequate for the shift selector rod.

7:2:8 My exhaust was welded solid until the turbo, so I removed the muffler support from the transmission. I supported the muffler with a jack stand, and it did not get in the way.

7:2:10 I was not able to remove the back up switch, but it did not pose any problems.

7:2:11 Remove the axles. This is easy, if you have the tool. As has been posted here http://www.924board.org/viewtopic.php?t=17156&highlight=triple+square, this requires a special tool. The link lists one source, you may also buy part number 2304 for about $7 from your local Napa parts store. This is an 8mm Serrated wrench, also called a triple square. This is NOT a double hex or a twelve point torx. My method was to tap the Napa item into the screw head with a half inch drive Craftsman ratchet handle. Then use an open end 8mm wrench with a life-time guarantee on the tool near the fastener. Have an assistant hold the brake rotor, pre-stress the tools then whack it with a 4 pound hammer. Then slide a slim profile ratchet wrench on the tool, and go to town. Rotate the wheel opposite and repeat. It was easier to disassemble and reassemble alternating like one would with lug nuts on a wheel. There are 12 bolts, each with about 30mm of thread, the ratchet is key. I had one non-standard fastener that I used a regular 3/8 drive hex key on, due to clearance, it was way easier to get torque in the right place with the Napa tool. The left axle can rest on the exhaust pipe.

7:2:12 OK. Here’s what Hayne’s doesn’t mention. There are two inspection holes one large one in the bell-housing, and another small one about 6 inches toward the front of the car. Have a friend depress the clutch while you turn the drive shaft to get access to the screws. The shaft clamp is about 8 inches long and can be loosened at either end.

7:2:13 There are many $40 transmission jacks out there that combine with a good floor jack. Buy one. Use it.

7:2:16 The plastic guide tube can also be slid forward and out of the way.

7:2:16.5? You see, I didn’t find the other hole I mentioned in 7:2:12 for several more steps… and about that 4 pound hammer I mentioned in 7:2:11…
Here’s what happened, the transmission slid smoothly back, then hit the spare wheel well. We pushed, we pulled, we muscled the box, but it still would not come out. So the fools before me must have put a transmission that wasn’t quite right. Right? There was a big dent in the spare tire well where someone before me had beat in. So, out comes the hammer. I just beat the spare tire well in another inch or so. This is about when the rear bumper fell off. Eventually, the transmission came out. It was no different in length from the new one. For those out there that are offended by my brutal treatment of a Porsche, you should know that several people have offered to buy my car for parts. It’s never going to be a museum piece and a learning tool.

7:2:24 This is where the extra inspection hole comes in handy. The aft clamp screw must pass through the valley in the splines, the forward screw adjusts the sleeve’s position for length.

Hey! Is there oil? Now might be a good time to freshen the oil. The plugs will come out with a 17mm hex plug. Mine was from Harbor Freight. I can’t tell you for sure that it is not 18mm. Heat the new gear oil in a bath of hot water while the old is draining. Having the oil at about 110 degrees will make it fill much quicker. If you have never changed this oil, use about 3 feet of clear tubing that fits over the nipple on the bottle.

7:2:25 Don’t be surprised if the transmission shifts perfectly without adjustments.

Unfortunately, it is very likely that I damaged bearings in the drive shaft or clutch while muscling the transmissions out and in. I guess I will get to do this all over again soon.