Installing a Behlen Overdrive Unit

heckatc

New User
My old man and I are in the the process of installing a Behlen Overdrive unit on a 1936 Unstyled A. We have removed the old shafts and placed the new Overdrive shafts in. All gears and shifter plates and shifter shaft are all back in place. Our only issue right now is we can't get the snap ring back inside the housing of the case the keep the sliding shaft from sliding out. We are wondering if it is even possible to get the new sliding shaft set in far enough to put that snap ring back in? Once we put the Overdrive box on the sliding shaft doesn't appear to be able to move far enough to cause any issues there. We are just curious if we would be all right to finish assembling things as is?
 
I have installed 2 Behlen Overdrives in A's. One in a 36 and one in a 38. Lots of fun on the road.....The 38 install was pretty cut and dry. The 36 was a different ball game. On the 36 the Behlin shaft had to be machined to let the snap ring fit in the case. Sometime in 37? the original stock gearing was changed I guess. To close the speed gap between 2nd and 3rd. I tried to look in the parts book to figure what serial number the change was made but my ole' brain couldn't figure it out. I can tell you the 36A is about 4mph faster than the 38A. With all that being said...I would not recommend leaving the snap ring out. Oh, and be sure to install the flywheel spacer with the oil slinger drive pin on it. Any questions? Life is Good Dave
 
Thanks for the response! We have the shaft out and in the machine shop. Hopefully we will have it all back together next weekend. The kit I bought didn't come with a spacer we were just thinking about fitting a washer in there?
 
The flywheel spacer is about 3/8 to 1/2 inch wide. it has a square notch on the flywheel side and a square peg on the engine side. Those have to be in the spacer to drive the oil slinger on the crankshaft. Your flywheel will end up not going on the crankshaft by about 1/4". I have had several guys tell me my flywheel is loose, until I point out the spacer. I had to make my own spacer on the 36A. Not to hard of a job. If you need some measurements let me know and I see what I can do. I can't remember if I took pics or not but I will check. Life Is Good Dave
 
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Hey, one more thought..This would be a good time to drill and tap drain and fill plugs in the reduction gear cover if yours has not been done already. I also have pics of the gaskets I had to make for the install if you need any. You are making your own gaskets right? That reduction gasket is a bit salty. Life is Good Dave
 
As far as gaskets though throughout the whole restoration
we've bought some. Made some. And sealed some stuff with
silicone. Thanks for the pic of the spacer. My brother in law
just said he could whip that up easy for us.
 
I remember when I had an old A with one on it,,it was very close to the flywheel,,I'm thinking that it didn't have a spacer,,it was a 38...
 
Transmission all back together! Thank you for all the advice!
Can't believe how easy it went together once we had that
shaft machined. We had a hiccup with the clutch last weekend
so we didn't get it going down the road again yet. I'll be able to
get back up north next weekend and hopefully by lunch time
Saturday I'll be taking a 20mph cruise down the road!
 
It probably won't be 20, more like 18 ( by my Garmin) But those Red H's and M's will not catch you. Be very careful if your steering and brakes are not 100%......enjoy Life is Good Dave
 
Perhaps I should add...That my 36A has 13.6/38 new tires and my 38A has 13.6/36 new tires. The gearing difference between the 38 and the 36 has some to do with top end speed but the tire size also affects it as well. I get about 14MPH from the 38A and about 18MPH from the 36A. My hand held tach shows top engine RPM about the same. I must admit, as much as I like the 36A, the 38A is better for group tractor drives. Life is Good Dave
 
Finally got the tractor running again today and tested out the
Overdrive. It works great! Got it up to 13.1 mph. We think we
need to adjust the throttle linkage a bit so I'm sure there is a
little more speed in it. But we are happy it'll go fast enough for
me to be allowed to drive it across the Mackinaw Bridge this
fall! Thank you very much Dave for all of the advice and help!
Wouldn't have got here without ya! I owe ya a brew that's for
sure!
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Oh man, now I'm po'ed......You didn't tell me you were going on the Big Mac drive.....I've had that on my bucket list for to long. I just turned down another chance to go last week. I have everything I need to go, I just can't seem to get the timing right. You dog.....lol If you don't mind me asking, where do need to go to pick up my cold brew?
I take it yer steering is tight enough? It does make these unstyled more versatile for sure. How do ya like having 3 gearshifts? Actually it felt good to be on the helping end instead of the needing end, if you know what I mean....glad it worked out... Life is Good Dave
 
Ya definitely gotta do that Bridge drive. We've done it all 9
years so far. It's an absolute blast! Well I live and work in
Kalamazoo, Michigan and my old man lives in Marion,
Michigan. Our tractor club is called the Greasy Fingers Two
Cylinder Club and we usually have meetings in Big Rapids,
Michigan.

Only went on about a mile ride with it yesterday, but
everything felt good to that point. So far steering feels good on
it. Lol yeah the three gear shifts seems a little cumbersome
but I'll get used to it in no time!

I strongly encourage ya making it to the Bridge, ya won't
regret it. If you watch Small Town Big Deal on the RFD
channel they had a feature on it a couple 2-3 weeks back. My
dad took the cohost Jan across on his 50 so he got a decent
amount of air time on the episode.
 
Yeah yer right, I gotta make that drive sometime. It's about 525 miles from here and an 8hr drive one way. I envy you for being so close. If I it make up, I'll be expecting more than one cold brew.... :lol: Just sayin'.......Glad it seems ok, now for a trip around the block. Put a few miles on her and get used to yer new tractor..... Life is Good Dave
 

Hectatc...just noticed it's been a year since the install. Care to give an update? did you take it on the Mac? Dave
 

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