T-5 transmission in 1/3 scale

[gbritnell]

Yes I have a DRO. It's one of the Chinese scale types but it has worked good for me.
I haven't scrapped any parts yet. Like I said, I've made a few 'errors' but all were fixable. I guess if I was a purist whenever something wasn't 100% I would start over but as anal as my wife says I am I'm not that far along. When I learned my trade I was taught that if something was fixable it wasn't junk.
When doing many hundreds of steps on a project like this the hardest part is maintaining concentration, wife questions, telephone calls, where the hell did I set that tool, etc.
gbritnell

[wierdscience]

I was always told the difference between an apprentice and a master machinist is that the master knows how to fix his mistakes and I don't see any mistakes George

[lynnl]

Someone earlier used the term "awesome!" Ordinarily I hate to hear or read that word which is so overused by the teenage crowd, as to have become meaningless.
...but in this case it does truly apply, literally!!

Following this thread has been a real treat!

[saltmine]

"I chucked the part and indicated it concentrically and then set one of the center teeth on the cutter to the center axis of the shaft."

That, and the photo was what I've been looking for. Making gears, I never could get the involute cut properly on both sides of each gear tooth, and sometimes ended up making gears that looked more like wide saw blades.

Great work, gbritnell! While I was working, I had many of these 5-speed transmissions apart. Through the years I learned a great deal about them, and their strengths and weaknesses. Borg-Warner really knew what they were doing.

Most people don't know it, but Ford, GM, and Chrysler all used T-5 transmissions. Several high-performance Japanese brands did , too.

Borg-Warner made their cases, gearsets, and tailshaft housings all interchangeable, to fit the application. Last time I looked, GM alone had six different gearsets for the basic transmission case, and five different shift lever locations on the top cover and tailshaft housing. And.....no gaskets.

The last T-5 that I tangled with was the one my brother and I installed in his wife's 1931 Ford Model "A" Roadster pickup. It has a mild 8BA flathead V-8 in it, and originally had a Ford 9-bolt side cover, three-speed, out of a 1951 Ford sedan. We had to saw the lug off of the bottom of the tailshaft to make it fir. But, the driveshaft, and everything else fit well. My brother's wife had to make new floorboards and transmission tunnel for it, but it was worth it.
With 5 speeds and a 30% overdrive in fifth gear, the old flathead performed flawlessly (almost like the ratios were designed specifically for it)....Gas mileage went from a paltry 18mpg to 26mpg, and the car is much more comfortable on the freeway.

The T-5 is probably one of the best manual transmissions available, even bettering the smooth shifting Italian and British gearboxes by a large margin.

[gbritnell]

I managed to get a little time in on the trans. I cut the remaining gears for the main case plus the overdrive gears that are located inside the tailshaft housing.
As I had mentioned earlier the gears were cut with homemade hobs mainly because of the irregular D.P. (36 and 40) The overdrive gears are 48 pitch for which there are commercially made cutters but I figured being as I was making the other hobs I might as well make that one also.
I started with the countershaft thinking that it would be easier to adjust the individual mainshaft gears than trying to recut the countershaft. After touching the cutter to the blank I went in the required depth (add+ded) and added .001 with the hope of not having to recut. To my surprise and pleasure each of the mainshaft gears and the overdrive gears fit perfectly. Well perfectly might be an overstatement but there was no binding and negligible backlash so for cutting with a homemade cutter I would class that as perfect.
The first several pictures show the gearsets in the main case. The only thing remaining is to cut the key slots in the spline bushings to lock them to the mainshaft.
The pictures of the overdrive gears show the shift collar in the disengaged and engaged positions. The shifting fork will straddle this collar.
The 2 remaining pictures show a closeup of the reverse idler gear. This is a 36 pitch gear. You can see how well the involute curve was formed on the teeth using the hob. The gear still needs to be deburred and cleaned up but I'm quite happy with the results.
gbritnell

[gbritnell]

Overdrive gears

[gbritnell]

36 D.P. gear cut with hob.

[Willy]

Stop it George, you and your mill/drill are embarrassing the hell out of the rest of us.

Seriously though you could knock me over with a feather, very impressive work.
As I look at your work I keep having to remind myself that I'm looking at a 1/3 scale model and not the real thing!

Thanks for sharing your work with us, very inspirational indeed.

[Bill Pace]

I had complemented your work earlier, but I have to give praise again!! and on a mill-drill!! Hah! I wonder if any of those "purists" proclaiming all the sorry attributes of a mill-drill (and others along that line) are even following this - probably too embarrassed.

Those gears are sooo nice, could you show a pic of one or two of your hobs, and maybe a few comments on your construction of them.

[saltmine]

Beautiful job, George. My one criticism is the gears in a full-sized T-5 are all helical pitch. But, I can hardly expect anybody without access to a five axis CNC mill to even begin to contemplate helical gears.

There was a time when all cars had straight-cut gears, and bevelled gears in their differentials. Characteristically, straight-cut, or spur gears tend to be noisy, and not quite as durable as a helical gearset mainly because the helical pitch carries a much wider tooth contact pattern, and the teeth overlap, making it much quieter.

Other than that, your 1/3 scale T-5 looks quite impressive....I'm pretty sure that I could never duplicate your work, myself. Kudos, George...