Tech Articles

August 2003

944 Shift Rod Repair

By Steve Grosekemper

Whenever I start a large project I take a look at surrounding items to see if there is anything else in the area that might need attention. In the case of 944-transaxle and/or clutch removal one of the things I look at, amongst others is the shifter and shift rod. The shift rod is a tube, approximately 5 feet long, that connects the shifter itself with the transaxle shift selector shaft. This rod can only be removed with the transaxle out of the car.

It is quite common to have an extremely worn shifter cause loose shifting in these cars. This is caused when the horizontal pivot pin in the shift handle gets worn due to galling as a result of poor lubrication. The common repair is as simple as replacing the shift handle. The catch comes in when a worn shifter has been allowed to damage the actual shift rod. In these cases the sleeve that the pivot pin rides in can be damaged as much as, if not more than, the shifter pivot pin itself. Normally, replacement of the shifter and shift rod is the only way to restore the shifting accuracy. The problem comes when paying for these parts. While the shifter itself is only $46.75, the shift rod is priced at a lofty $200.00+.

Note the excessive play in the shifter pin

Even after a new shifter is installed.


The solution to this problem is quite simple. While I would like to take full credit for this repair I cannot. I will take credit for being observant however; for the repair pieces come from a 924 with the Porsche G31 transaxle. (This is the one with reverse gear above first like pre-72 911s and all 914s) In this transaxle the shifter has two shift rods that connect just like the single 944-shift rod does. But instead of running the pivot pin metal-to-metal with the shift rod there are two plastic bushings used, Part # 999.924.002.40 @ $1.40 each

Where the old pivot pin was metal-to-metal we now have a

Plastic bushing for smooth trouble free operation

The shifter pin uses the same 10mm diameter in the 924 and 944. So in order to fit the 924 bushings the stock 944-shift rod you must first bore out the pivot pin sleeve to make room for the 924 bushings. This seems like a simple procedure until you realize how critical the tolerance for this actually is. Too small and the linkage will bind, and only 0.2mm too large and the play will be unacceptable. (Guess how I know)

After quite a bit of measuring and searching for just the right reamer for the job I came to the conclusion that it was just not readily available. So I started playing with what I had (with a used shift rod as a guinea pig) and discovered that a common high-speed drill set was all that was needed. It is critical to make smooth straight cuts when increasing the pivot sleeve size. So I started with the smallest drill bit that was larger than the worn shift rod pivot pin sleeve inside diameter.

This was a 13/32" drill bit, and I increased the sized gradually with 27/64" then 7/16" and finally finished the cut with a 29/64" drill bit. This final size equates to an inside diameter of 11.50mm. The new shifter with the new 924 bushings installed has an outside diameter of 11.40+mm. This leaves enough clearance for lubricant with no extra room for sloppy shifting.

The standard 944 shifter uses several spacer/washers to preload itself into the shift rod. Since the new bushings have shoulders there is no need for any additional spacers. In some cases the shifter may be too tight and need the shift rod sleeve width to be filed down slightly to decrease preload on the c-clip.

After all the modifications have been made it is best to make all your final adjustments with the shifter and shift rod out of the car. After you are sure of the final fit you can reinstall the shift rod, transaxle and shifter, in that order. Be sure to use good high temperature grease when reassembling the shifter to the shift rod. But you can rest securely, knowing that if your shifter ever does become sloppy, the replacement of two $1.40 bushings will be all it takes to make things like new again.

 

Good Luck

 

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