Time Faux A Change
Dressing up a banjo rear for a quick-change appearance
Andy Bolig - January 25, 2013 10:00 AM
We started with a pretty good rear out of a ’40 Ford truck. It was rebuilt several years ago by the previous owner and has spent more time on the shop floor than the highway.
It no longer wears the enclosed driveshaft, or torque tube housing but that’s OK, because we won’t need them. We’re using a different engine/trans configuration with an open driveshaft.
Speedway Motors has this ingenious conversion kit that has everything necessary to adapt to the splined shaft and provide a yoke for the universal joint. It contains all of the gaskets, bolts and seals for a complete conversion.
We ordered a full set of gaskets from Speedway because we didn’t know what we might run into. The large round gaskets are different thicknesses to set up the proper carrier bearing pre-load. We didn’t split the cases so didn’t need to go through the process of trial and error to shim the housings.
We wanted to keep the freshly-machined parts looking new, so we treated them all with Rust Prevention Magic. This durable treatment fills in the pores to protect them from oxidation and leaves a natural finish.
We began assembly by installing the seal into the front housing, using a plate of steel to seat it fully without damaging it.
Next is to install the housing onto the rearend. There are drain-back grooves that need to align with the drain hole in the differential housing. We put some Right Stuff gasket seal around the perimeter to help seal any potential leaks.
With the housing lightly bolted in place and the pinion seal lightly oiled, slide the front yoke onto the shaft. There is a pin hole in the shaft that needs to mate with the holes in the yoke, and the yoke will help center the housing as it slides onto the shaft.
Tap the retaining pin into the hole.
The holes in the yoke are threaded for the two Allen-head set screws. We applied some Loctite and installed the screws, making sure both went in the same distance, thereby centering the pin in the shaft.
The conversion is complete. Speedway offers kits for the six-spline shaft (like ours) or the earlier 10-spline shafts. There is also a kit for Model A owners. All kits are bolt in with no machining.
Throwing some form in with the improved function, we opted for Speedway’s quick-change-look rearend cover (part number 91647901) to help our rearend look the part.
To mount the faux cover, you can either drill and tap the housing, or weld nuts onto the housing to bolt the rear cover in place. We used barrel nuts welded to the housing. They are a little wider than typical nuts to allow for welding and additional strength.
Thread the bolts into the barrel nuts just enough to hold everything and tack the nuts to the housing. Then remove the housing and finish-weld everything. Using the bolts helps keep the nuts aligned with the holes to reinstall the bolts.
We painted the differential housing with a matching silver to help hide its lack of additional gearset under the rear cover. Other than the lack of a telltale whine, it’ll be hard to tell the difference at speed.
If you were to go back before chrome dripped from every corner of our beloved cars, you would notice some very ingenious speed parts that are still highly sought after today.
One such item would be the multi-purposed quick-change rearend. They’re extremely popular with the early speed freaks, and REALLY expensive! They’re known for their durability, have proven themselves throughout the decades and even today, are coveted jewels residing under the blessed builds whose owners are lucky enough to have sourced one.
Quick change assemblies were available as speed parts for the ’35-’48 Ford “Banjo” rearend and aside from the distinctive whine that their straight-cut gears emanate, they also provided for “quick changes” of the differential’s gearing by swapping out the matched set of gears that resided behind the unmistakable cover protruding from the rear of the differential.
The history of the quick-change rear was forged throughout the decades on about every surface where speed was more than simply a desired characteristic. Quick-changes found their way onto dry lakebeds, early wooden (and later brick-laden) superspeedways and even found short-duties on the quarter mile with amazing regularity. Their broad scope of use and their penchant for durability has secured a spot in the hearts and minds of hot rodders, even if their cars may never see competition at any level.
Many enthusiasts would love to have a Winters or Halibrand quick-change rear under their cars, but might not want to commit the cash that one of these whiny beauties command. Thankfully, enthusiasts who would love the looks of a quick change without the cash outlay have a solid alternative. While there isn’t much that’ll replace the sound that comes from one of these while travelling down the road, Speedway Motors in Lincoln, Nebraska, has provided a way for you to get the LOOK that you’re after. Speedway has been selling go-fast goodies since 1952 and yes, if you HAVE to have the real-deal under the floorboards of your ride, they can provide that. But if the look of a quick change is what you are after, they also have all the components that’ll make your ’35-’48 Ford rearend look like a million bucks.
There are a couple of different kits available, depending on your application. Up until 1949, the driveshafts under Henry’s haulers were enclosed in a housing that connected directly to the rear of the transmission with one universal joint. As the suspension moved, the joint would articulate inside of a ball-type of housing that bolted directly to the transmission. If you are using a newer style of transmission, this system is no longer utilized and therefore, you must design a new way to connect the transmission to the differential, via an open driveshaft. You will also need to utilize a different means of mounting the rearend as the original strut rods bolted directly to the torque tube that encased the driveshaft. Many enthusiasts utilize hairpin radius rods or simply use the original strut rods mounted to a crossmember or similar mounting surface.
We will be using an open driveshaft with our 1940 truck rear and we needed to use the open driveshaft conversion kit (part number 9191105) for the six-splined shaft. Some earlier rearends had a 10-spline shaft, so be sure to find out which version you have before ordering. We also opted to install Speedway’s quick-change-look cover. While it doesn’t improve the performance or durability of our rearend, it sure does do a LOT for style points! Follow along and we’ll show you how easy it is to go from boring banjo to faux quick-change for your ride.