Posted by Joe Lorenzino on May 05, 1998 at 01:58:06:
In Reply to: Re: overdrive posted by Jim Ferguson on May 04, 1998 at 21:02:50:
No, I haven't seen one of these in a PW or M37. Both of these trucks are Very Scarce up here in my area, and of the few I've seen, none have had any drivetrain modifications.
A Lenco "section" containing one planetary set is about 8" in length. They are splined front and back, and fit end to end to form a trans with as many gears as you want to stack together. They shift by tightening an internal clutch pack which locks up the gear set to give direct drive. Most of them use an air pot or adjustable over-centre lever to do the shifting. I have been out of racing for a few years, but in that time, most of the top running cars have gone to a Multi-Stage Clutch system (which totally does away with Any form of transmission) so there may be a few more old tranies to be had. Some of the modified tractor pullers up here were using 1 or 2 Lenco sections between the engine and the "regular" tractor trans to give them some "shiftable" gears during a pull. I have no direct experience with the Nash tranny, but believe it is even shorter than a Lenco section. The beauty of the Nash, is that it is Built to be able to change ratios easily, and at low cost. It uses 2 sets of spur gears, one of which is a standard "Quick Change" set. Each "set" provides 2 ratios, as they can be swapped to provide over OR underdrive, so the same unit could provide both an overdrive for the highway, and with a few minutes work, give you another underdrive ratio for the trail. Carry onother gearset with you, and you could have a 23% overdrive, and a 56% underdrive to replace it with on the trail. Sounds real good, but I don't know of anyone who has tried it. Good Luck J.V.L.