Speeding Up The Early Jeeps - Old School

The Spicer 18 transfer case first appeared in the MBs and GPWs of World War II and was in production up to 1972 and came in 13 different versions over the years. Compact and quite strong, it is still being used by off-roaders today, and, in fact, there are several companies that specialize in custom gearing for them. One of the drawbacks of the intermediate gear design is that it rode on a shaft supported by a series of small needle bearings. This shaft never received sufficient lubrication, and both it and the bearings would wear and become quite noisy. It's also thought by some that this shaft would actually flex under load, contributing to the wear and noise. Spicer, in an effort to solve the problem, increased the size from 31/44-inch (as used in the MB versions) up to 111/48-inch in the early civilians and finally ended production with 111/44 inch shaft. I believe it was Archer Brothers Jeep in Hayward, California, that came up with a way to eliminate this shaft and troublesome needle bearings. The company machined the ends of the intermediate gear to accept tapered Timken bearings. However, it was difficult to always get the correct bearing adjustment. Now it seems that with superior lubricants, the way to go is with the original design.

Believe it or not, there actually was a three-speed version of Spicer 18 built back in the 1960s. Thing is, it wasn't built by Spicer. It was made from plate steel that was welded together and then heat-treated to relieve the stress before being machined. It had to be about 1962 or 1963, and I was for some reason or another in Buschert's Machine Shop in Hemet, California. Harry Buschert was showing a buddy and I this prototype that he had developed. I don't think that there were over a half dozen ever made, and each one was a bit different. I wouldn't swear to it, but I believe it had a lower low range than the normal 2.46 gearing, a 1:1 high range, and an overdrive range. Harry was on the right track and way ahead of his time when he built these. Little could he imagine that some day a three-speed and a four-speed transfer case would be in production.

Today we have a wide range of transmissions - from standards to automatics - available, including six-speeds with built-in overdrives. Plus, we have adapters available to put just about any transmission to any transfer case your mind can imagine, as well as separate overdrive units and gearboxes that fit either in front of or in between the trans and transfer case. The old standbys - the Spicer 18s, Dana 20s, and Dana 300s - are being modified with lower gears and stronger parts to survive four times the horsepower and torque they were originally designed for. Transfer cases that were originally designed for much larger vehicles, not even carrying the Jeep nameplate, are being successfully used. Best of all, there are at least three custom-built transfer cases that can withstand all the abuse you can deliver. Sure beats the heck out of rebuilding your T-90 several times a year and new bearings for your Spicer 18 when you could no longer stand the gear whine.