I've been trying to figure out a 717.400 alternative for a while, preferably one that is plentiful and cheap . After doing a lot of research on the Toyota W59, I've switched focus to the AX-15 found in 2WD Jeep Cherokees and Dodge Dakotas, among others. The AX-15 is considered one of the best 5-speeds ever put into a Jeep. It's very durable, and able to take about 300 HP/300 lb-ft reliably. The ratios are pretty similar to a 717.400:

..............AX-15..........717.400
1st...........3.83.............3.82
2nd...........2.33.............2.202
3rd...........1.44.............1.398
4th...........1.00.............1.00
5th...........0.79.............0.813
R..............4.22 (!)........3.705

The first attachment on this post is a spreadsheet comparing the speeds at various RPMs of a 717.400 to an AX-15 when both are mated to a 3.07 rear end, along with an AX-15 mated to the 2.88 rear. As you can see, the ratios are extremely close (sorry for how messy the columns are). Using the 3.07 as an example, the car hits 2000 RPM in 5th at 60 MPH, 2300 RPM at 70 MPH, and ~2600 RPM at 80. This means that running average speeds on the highway with this thing would put you right at the peak of the OM617’s torque curve, a good thing for both economy and power.

Of course, the main issue with using an AX-15 is fitting it. I’ve identified and tried to resolve all the main “problem areas” that need addressing: mating to the engine, flywheel/clutch, starter, fitting in the tunnel, mating to the driveshaft, how to locate the shifter, and how to run the fluid lines. I’ve attacked them point-by-point below, starting with mating to the engine:

Mating to the engine, clutch & flywheel, starter

Mating to driveshaft

The shifter

Master/Slave/Fluid lines

Extra flywheel weight

Fitting in the tunnel

Attached Files

Gear ratio comparisons between AX-15 and 717.400.pdf (292.8 KB, 182 views)

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