08-04-2022, 08:45 PM | #1 |
Member
Join Date: Sep 2010
Location: Smithtown, NY
Posts: 45
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AA Underdrive
Hi Group, Has anyone heard of a "28/'29 AA Underdrive unit accessory?
Are the units worth anything? I would think an overdrive unit would be desirable. Also I have a short driveshaft. Are they of any value? Thanks for your reply. Wayne Duprez Model A Club of Long Island |
08-05-2022, 06:48 AM | #2 |
Senior Member
Join Date: Mar 2013
Location: Hudson, NY
Posts: 511
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Re: AA Underdrive
The underdrive unit you have may be a standard Ford unit called a Dual High. In my opinion, highly UNdesirable. this gives you a stump puller. If the short shaft you have is the same length end to end as the dual high, it is VERY desirable...
Post a photo, please Frank |
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08-05-2022, 09:21 AM | #3 |
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Location: Cow Hampshire
Posts: 4,188
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Re: AA Underdrive
As mentioned, the Dual High term is a misnomer. It should have been described as a "dual-low." It is an "underdrive."
A typical Ebay price for an AA Dual High unit is $75 to $100. I know. I explored briefly the possibility to install the Dual High BACKWARDS in a car rear axle propeller shaft assembly - and thus create an "overdrive." Most large truck users of that era IF they wanted to increase the top speed of their AA trucks (typical 4 speed maximum road speed with a HIGH SPEED rear end is 45 mph) was to install a "Warford" overdrive transmission. This was a TRUE overdrive designed to replace the Dual High at the intermediate shaft location. The Dual High was Ford produced and pretty much aimed at the 28-29 AA truck 3 speed truck market. The 30-31 and beyond AA 4 speed was usually provided with a "intermediate shaft" although there was room for the Dual High or something else, which could be applied. Methinks most went for the aftermarket Warford - which was available from Ford dealers. The Ford "Green Book" (published first pre-WWII and available until the mid-'50s) described the possibilities and parts required to set up a AA/BB & beyond truck to a users requirements. Today there seems to be about equal number of extant Dual Highs out compared to extant Warford units - although today the Dual High can be had for less than $100 and the Warford sells for upward of $1000. We drive faster today - that's why. Joe K
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Shudda kept the horse. Last edited by Joe K; 08-05-2022 at 10:35 AM. |
08-05-2022, 09:52 AM | #4 |
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Join Date: Aug 2021
Location: alberta canada
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Re: AA Underdrive
i have worked on an AA with a high/low range on the back of the normal 3 speed. Grain truck. if that is what you are talking about.
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old ugly my old father-in-law told me. "listen close when people tell you how to do stuff they may know something. then do it the way you want." Last edited by old ugly; 08-05-2022 at 10:22 AM. |
08-24-2022, 02:54 PM | #5 |
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Re: AA Underdrive
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