Model AA trans problems

C

ctdoodlebug

Junior Member
Hello all,

I am fairly new to model a's but intrigued by them non the less! I have 1931 AA doodlebug. Used it all summer long no problems, parked it last week in the barn. Went out yesterday to move it and the transmission is making a loud clunk clunk clunk, almost like something is stuck in a wheel. 1st or reverse it doesn't matter. Any ideas?! This thing worked flawlessly last weekend. It has an AA 4 speed with has been cracked and repaired several times.

Can I swap a 3 speed out of a car as a direct bolt in? Any difference in U joints or length?

Is the first gear on the 3 speed pretty low? I use this to pull wagons and push snow so i need a fairly low first gear.

Thank you for any ideas!

Paul from CT
 
The car three speed requires a different bell housing and I believe the universal joints are different. I would start by taking the shift tower off of your transmission and having a look inside. It could be something relatively simple or it may not be the transmission at all. If you need used gears, I've got plenty of them and you'd be welcome to them for the cost of shipping. Also, the car trans doesn't have a low first gear like the 4-speed AA trans does, so there is that to consider also.
 
You may have a broken gear.

The Ford four speed AA ****** has what is best described as a "creeper gear" in first gear. Not so much the 3 speed car/truck ****** - the same was used in both car or truck up until about October 1929 - which is why Ford allowed as option to buy a "Hi-Low" gear which effectively gave the AA trucks 6 forward speeds - at least one of these being equivalent to a creeper.

A 3 speed car ****** CAN be a bolt in - the four speed ****** was given as an option for those with automobiles desiring a power take off. No change in length. But the exchange takes more than just the substitution of the ******: you need certainly the AA bellhousing and brake clutch parts that matches the ****** and a universal joint of specialized configuration to mate from the Borg Warner 4 speed to the Model A rear end.

I went through a similar exercise assembling the parts to go from a 4 speed Borg Warner ****** to a Warford Overdrive (designed originally to mate against the 3 speed ******.) And from the Warford to the Borg Warner rear differential/axle on my AA chassis (sniff - where did you end up and why did I sell you so cheap?) The specialized univeral joints have yoke half as is used on the Model A, with the matching yoke being made for the Borg Warner spline. For my AA I needed two of these. For your application you need only one.

These mix & match universals can be found in the flea markets - but might take some searching. Another source is Dana-Spicer who made universals for Ford "back in the day" and continue this tradition to today making an equivalent universal. And parts . Which are available to assemble the universal you need but there may be waiting period/special order issues.

Cracked and repaired several times has an ominous connotation. You could have the classic Borg Warner "smile crack" which is a sign of a compromised transmission (smile crack comes usually from the ****** being filled with water and freezing - but can be caused by abuse.) Smile crack can be seen as a semi-circular crack on the lower "belly" of the transmission: it can be repaired (I've seen it done by brazing) but can be a sign of misalignment between the internal parts of the transmission - and may cause the symptoms as you're seeing.

You might want to remove the top of the ****** and check out the positions of the "H" shifter pattern. Put the ****** in neutral and remove the top and (hopefully) find the two shifter sliders grooves opposite each other. (neutral, remember? This is where the right shifter HAS to line up with the left shifter to allow you to go between left and right in the lever action.) You may have one shifter out of sync which is causing the gears to clash. While you have the top off, take a look at the release lever shifter which you have to press down to allow the ****** to go into reverse gear (third shifter rail): this should be engaged as a lock preventing movement of the shifter lever to go to reverse.

Finding everything o.k. then you might want to start checking out the classified for a replacement 4 speed ******. They can be had for fairly small money still, except for the ones that people have checked out and deemed AOK which sell for more. Even if you buy one from a basketcase AA, you likely can combine the parts of two trannies into one and make something that will work.

Hope this helps.

Joe K
 
What is the temp there? I saw a tractor once that had water in the bull gears, once it froze it created all sorts of clunking and bumping.
 
Where abouts are you located in CT? I would second taking the top of the transmission off to see what is going on in there. Do you store it outside or undercover?

Red
 
ctdoodlebug said:
...Is the first gear on the 3 speed pretty low? I use this to pull wagons and push snow so i need a fairly low first gear...
Click to expand...

First gear on a 3-speed (car transmission) is essentially the same as second gear on the AA (truck) transmission.
 
what eagle said

if cab is open, if there is a cab, rain can and will get past the shifter and accumulate in the bottom of the case. Once it freezes bad things happen. Have seen it a couple times on farm tractors
 
All,

Thanks for the replies!! I've seen the ice in tractors as well, but this is stored inside and it was a warm day. Unfortunately I haven't had time to look at it yet but might remove the top tomorrow and see what I find.

It doesn't sound like a 3 speed swap is the answer, I need that low gear...

Doug, thank you very much for you generous offer! I'll keep it in mind for sure!

Red, I'm in Suffield, CT, right on the MA border.

I'll keep you guys posted, Happy Thanksgiving to all!

Paul
 
Here's a pic
 

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Hello again,

I had a few minutes so I pulled the cover off. I found gear oil with some water in it but no obvious broken parts that I can tell. Going to bring it in this week and drain whats left of the oil and have a closer look. Figured I post my findings in the meantime.

One other question...the shifter itself has LOTS of side to side play, how can I tighten this up? Also, the reverse lockout is present but never worked in the 2 years I've been using this thing, could this be an issue?

Not looking to make this a show piece but it has to be reliable.

Thanks again for all your ideas!

Paul
 

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That is one ugly mess of oil and water. After you clean and rinse it out, then post another picture so we can better see the condition. Right now it looks like a lot of rust pits on the shafts and gears, but I could be wrong and maybe it's just the lube and picture.
 
It's been a while since I took a cover off a 4 speed. Could you get some more pictures of the front shifter fork? It looks like it's broken, but it's a little hard to tell form the photo. You definitely have some water in there. The play is probably the pin that holds the shifter to the tower. You could try the AA truck forums for help too. www.aa-fords.com

Red
 
Hi guys,

I haven't had a chance to get into it yet unfortunately...been under the weather! Perhaps tomorrow I'll it inside and tear it down.

Hey Red, do you know anything about a Model A swap meet tomorrow in Enfield, CT?! Thought I read about it somewhere, any idea what time it is?

Thanks!

Paul
 
Paul,
I am in Chicopee, I just took a GOOD four speed out of my driving truck. I took the shifter off and the rear gear that sticks out of the back, other than that it is a nice transmission. You can have it $40! My email is spdway1@aol.com - Don
 
Hey guys,

Just figured I'd give you a quick update here. Pulled everything apart this afternoon and found the front main shaft bearing to be no good AND the roller bearing fell apart in my hands. Luckily Don (spdway1) helped me out big time and got me another transmission. Already have the motor back in just need to finish up a few things in morning. Thanks to all that helped!!

Paul
 
Just to update you all,

Everything is back together and working great. My guess is the problem started with the shifter, it basically completed fell apart when I removed the tower. Probably got caught in 2 gears at once. So I pieced together one good shifter assembly using parts from Don's shift tower and mine. Good as new!

Thanks for all your help!

Paul
 
if you deside to change transmissions you would be better off getting another 4 speed transmission. the bell hosing is different, the u-joint is different and hard to find if you do find one Its probly around 200.00 or more for a good one. I now cuss I have one with a bad u-joint that goes from 6 splin to 10 splin.
 
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