Mitchell Overdrive Technique

[Smitty]

I have a Mitchell overdrive in my coupe. When climbing hills I will sometimes shift second gear and overdrive which works well. The tricky part is coming out of overdrive, gears will not shift smoothly out of overdrive and back into second gear. Shifting into 3rd then overdrive will not work well either. Gearing in 3rd would be much too slow especially with 3:54's in the rear.
Thoughts?


Thanks, S

[larrys40]

Smitty,
I do that all the time using it as a gear splitter in my '30 Tudor. After installing a good number of overdrives it sounds like to me the linkage may need some adjusting. Make sure nothings binding. If you're clutch is adjusted properly and carb idle is low and not too high you should be fine.

I would take a good look at your mitchell shift linkage and adjust. You can always touch base with Steve at Mitchell for advise on that.
All the best!
Larry Shepard

[MAG]

Just a thought...Is the Mitchel box full of oil.

[Smitty]

Thanks, the box is full of oil, thought the linkage is ok, shifts fine under normal. Shifting transmission is trickier when climbing or descending hills. this also true with normal shifting of the trans.... Everyone find this to be the case?
S

[31 Woody]

Our Mitchell OD shifts very smoothly and easily both in and out of OD. I would check the linkage adjustment as previously suggested. Also, is your clutch fully disengaging/pedal adjusted properly?

[apbright]

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Indeed, I would agree with others, that it would seem that there is something not quite right with your overdrive. That is, at least, if I understood the original post correctly, i.e. that after having engaged the overdrive in 2nd gear, it becomes difficult to re-engage the overdrive - either while still in 2nd gear, or then after having changed to 3rd gear. My own thoughts thus first go to the same as larrys40's, i.e. some kind of linkage problem, or then indeed per 31 Woody, incomplete clutch disengagement; through mine and others' experience, I've grown to have strong faith in the core Mitchell OD unit (5 years/32k miles, no issues on mine).

In case it is useful: I live up on a hill, and drive my Model A's every day up and down this hill, through several traffic lights, and then on the freeway, for a total of about eighth miles each way, plus typically another 5-20 additional mixed suburban/freeway miles during each day. I also have a 1:3.54 rear end, on a '31 Roadster and a '31 S/W Town Sedan; here are my shifting habits:

From traffic lights, in suburban streets:
1st -> 2nd -> 2nd+OD, 3rd

Onto the freeway:
1st -> 2nd -> 2nd+Od, 3rd, 3rd+OD

Up the very steep hill:
1st -> 1st+OD, 2nd...


It may not be the way 'you're supposed to do it,' but when shifting from 1st+OD to 2nd, or from 2nd+OD to 3rd, I always:
a) depress clutch
b) shift trans to neutral
c) shift Mitchell from OD to standard drive
d) double clutch
e) shift trans to next highest gear

It's a bit involved, especially so when going from 1st+OD to 2nd, but with experience is the only way I've found for grind-free shifts. It has the added bonus of giving the uninitiated passenger the impression that I'm casting a spell on my car.

Safe driving,

Andrew

[junk yard kid]

Mine does that when its cold. After its warmed up its not a problem. I imagine its cold in boston, maybe once it isnt winter it will be better.

[Synchro909]

Originally Posted by junk yard kid

Mine does that when its cold. After its warmed up its not a problem. I imagine its cold in boston, maybe once it isnt winter it will be better.

Yes, the Mitchell O/D unit doesn't like being changed when cold! Once it is wrm, I have no trouble but there is a technique to going from high second to standard top gear.

• 1. Clutch in
  2. Shift gear stick to neutral position
  3. shift mitchell to low range
  4. move gear stick into top gear
  5. Clutch out

While you are shifting the Mitchell, the gears in the gearbox are slowing down, making the next change possible. I've done it so many times, I don't even think about it any more.