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Rebuilding a T-90 and Spicer 18

Verne’s 1946 CJ-2a, Part 4.

Generally, magazine project vehicles are all planned out with an end goal in mind, some completed vehicle that is purpose built to accomplish some set goal. That's ideally how real 4x4s in the real world get built, and that's kinda what ended up happening with this 1946 CJ-2a. We bought it after wanting a fairly stock and unmolested flatfendered Jeep. Not because we don't think things can't be made better by modification (our life's work should be an example of the counter to that), but because it's sometimes fun to have a baseline of what a stock rig can do to keep things grounded and real. Especially when that baseline is set with the first full year of production civilian Jeep.

Plus there is some fantasy of being a grumpy old man in a nice old Jeep yelling, "Get off my lawn!" at the damned kids one day. Yes, we aspire to be grumpy old men . Last time, we showed you how we jumped through the hoops to find and get an old Go-Devil L-134 engine placed and running. It was a ball, and it was a major plus when we found out our $500 engine is a decent runner (it does have a slight knock). Next we had to get other bits of the drivetrain in working order. To us rebuilding them before we had a running engine would be, without doubt, getting the cart before the horse. So we took the original T-90a, swapped out its guts for some T-90c gears, which will give us a lower first gear, and tore the original Spicer 18 apart in lieu of new gears, bearings, seals, and more. Next time we'll show you what we did to get the axles up to par, and maybe someday we'll show you how we fixed the rusty floors on this old Jeep.

Last Time in Verne's 1946 CJ-2a Land .

Little house cleaning here to be thorough, the L-134 we bought for our 1946 CJ-2a wasn't quite right for the Jeep. The story was that it came out of a Willys truck, and that's fine as far as we are concerned, it was a bit newer than the Jeep, which meant it had the wrong engine mount/timing cover plate on it. CJ-2As, like military MBs and GPWs, had engines with a timing chain rather than timing gears and a different engine mount/timing cover plate. That meant that the front of our motor had to come apart, down to the timing gears, so we could change the plate from the later style (with one foot forward and one back) to the earlier plate (with both feet aimed backwards). With that done we could add the good, albeit used and old radiator given to us—yes, given to us by our very good friend Ward Williams. Ward is a great guy. We've said it before and we will say it again: Thanks, Ward.

Rebuilding the T90A to a T90C for More Gearing

Sadly, the gears in our T-90A were rusted to a point that they were unusable. There were teeth missing entirely. This left us looking for all new internals rather than just the bearings and wear parts. This means that this may be the perfect time to track down the input gear and counter gear from a T-90C, which has a deeper first gear as it was used in later Willys trucks with 4.27 axle gears and the slightly higher engine output from the F-head 134 4-cyl. The T-90C input gear has 16 teeth, while the T-90A has 18 teeth. Correspondingly, the counter gear from the T-90C has 35 teeth, while the T-90A has 33 teeth. Gearing changes from first gear of 2.798:1 for T-90A and 3.339:1 for a T-90C. Second gear is also lower going from 1.551:1 for T-90A to 1.851:1 for T-90C. Third gear is direct 1:1, and reverse is deeper for the T-90C with 3.798:1 T-90A) down to 4.531:1 (T-90C). The input and cluster gears are available in the aftermarket as used parts, but we also found a good used set. We used small hair rubber bands (stolen from our daughter) to hold the bearings in place for the counter gear. We replaced all the bearings and thrust washers and reused what we thought were good synchro rings. We were wrong. Don't be cheap—buy new synchros for your rebuild. We also locally found a rare and new old stock top-cover for a T-90A for an M38A1. This top cover has a tighter shift pattern and a more traditional way of securing the shifter cane to the top cover. It's more like a later transmission like a T-18.

Rebuilding the Spicer 18

The rebuild tale for our original Spicer 18 case is much less romantic than our rebuild of the T-90A modified to a T-90C in that it's just a standard rebuild of a boring old Spicer 18. Having said that, this is a great transfer case for low-horsepower applications like this. We do recommend using a rebuild kit from a well-known supply house. We love the Spicer 18 rebuild kits from Novak Conversions, and the one from Kaiser-Willys ain't bad, either. Next time we will show you some pics of the assembly from the rest of the drivetrain and possibly dip into how we repaired the rusty floors on this fine old Jeep.