AA transmission in an A?
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Chris Haynes
Well-known member
It will bolt in.
Fullraceflathead
Well-known member
I have 1928 Model A open cab pickup with the AA 4 speed transmission. It was retrofitted back in 1929 when the 4 speed 1st came available. The rpm drop in between gears is slightly less with the 4 speeds as the gear ratio is a little closer. First gear is a granny low and is really ideal for being in parades. In first gear you don't have to ride the clutch and wear out the precious babbitt thrust bearing material.
In normal driving situations you start off in second gear.
In normal driving situations you start off in second gear.
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Fullraceflathead
Well-known member
While you can bolt in the 4 speed transmission in place of the standard 3 speed it does require the AA bellhousing.
Fullraceflathead
Well-known member
4th gear is direct drive the same as a 3 speeds 3rd gears direct drive so the regular speed and top speed would not be affected.
Joe K
Well-known member
Everything you need to know is at Vince Falter's Fordgarage.com page. Link below.
https://www.fordgarage.com/pages/aafourspeedachassis.htm
As Vince explains, the 4 speed requires a special "coupler/bearing retainer" to go between the transmission and the universal joint - a situation that didn't exist in the AA trucks with their "intermediate" shaft.
At one time I had one of these transition pieces which I planned to use to adapt an AA for insertion of a Warford Auxiliary transmission in the intermediate spot - but that went with the rest of the chassis.
Read through other areas of Vince's description and you'll find out that the Model AA 4 speed is not the rock-ribbed performer that it became with adaptation in the later Ford 1-1/2 ton trucks. You want to be sure the 4 speed you have in mind is not "cracked." Somewhere he describes "I had to look at about 10 as-found cases before I found an uncracked one."
I have two - one is failed (kept for parts) the other is ok.
Joe K
https://www.fordgarage.com/pages/aafourspeedachassis.htm
As Vince explains, the 4 speed requires a special "coupler/bearing retainer" to go between the transmission and the universal joint - a situation that didn't exist in the AA trucks with their "intermediate" shaft.
At one time I had one of these transition pieces which I planned to use to adapt an AA for insertion of a Warford Auxiliary transmission in the intermediate spot - but that went with the rest of the chassis.
Read through other areas of Vince's description and you'll find out that the Model AA 4 speed is not the rock-ribbed performer that it became with adaptation in the later Ford 1-1/2 ton trucks. You want to be sure the 4 speed you have in mind is not "cracked." Somewhere he describes "I had to look at about 10 as-found cases before I found an uncracked one."
I have two - one is failed (kept for parts) the other is ok.
Joe K
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Flathead
Well-known member
When I bought My 30 Tudor it had a AA four speed that someone had installed, it worked OK and I assume it was for parade use. I replaced it with an original style 3 speed.
When I pulled up the floor boards and looked at that 4-speed I could just hear the frame whimpering from all that weight on the engine mounts. Yes, my frame is sagged at the mounts.
When I pulled up the floor boards and looked at that 4-speed I could just hear the frame whimpering from all that weight on the engine mounts. Yes, my frame is sagged at the mounts.
Joe K
Well-known member
I haven't examined the bearing retainer/u-joint aspect since I sold the AA Chassis and the Warford Auxiliary transmission. But if memory serves, you can use the usual truck type retainer and a mix/match U-joint providing the assembly is checked for U-joint yoke clearance inside the retainer. Modern U-joints make this easier as they run "smaller." The rear axle ends up less than an inch away from its planned position. Probably could be accommodated in the rear axle spring and a brake rod adjustment.
The mix-match U-joint is interesting as the input side is 4 speed/10 spline and the output matches the Model A rear axle driveshaft at 6 spline.
Joe K
The mix-match U-joint is interesting as the input side is 4 speed/10 spline and the output matches the Model A rear axle driveshaft at 6 spline.
Joe K
Fullraceflathead
Well-known member
When I removed my transmission to do a clutch on my truck I found that special bearing retainer was not there it has the standard thicker 1 it doesn't affect anything the rear spring just flexes a little bit further back I believe the difference and thickness is 3⁄8 of an inch.
1955cj5
Well-known member
My '29 ccpu had a four-speed when we bought it in 1962. No idea when it was installed. Certainly was not for parades...the bed had 1/4" plate bottom and the rear crossmember was broken and patched from repeated overloading...kind of cobbled together but the truck was definitely meant to be used.
It was noisy and though many parts for the four-speed are available I could not find a cluster gear shaft or the bearings.
Anyway, here they are side by side...
It was noisy and though many parts for the four-speed are available I could not find a cluster gear shaft or the bearings.
Anyway, here they are side by side...
Attachments
Joe K
Well-known member
Cluster Gear Shaft BB-7111 (was AA-7111)
Bearings (Big) BB-7118
Spacer BB-7115
Bearing (Small) BB-7120
In nomenclature it sort of follows the same parts in the Model A 3 speed. But everything is LARGER, of course.
And not available from the usual Model A parts houses.
Joe K
Bearings (Big) BB-7118
Spacer BB-7115
Bearing (Small) BB-7120
In nomenclature it sort of follows the same parts in the Model A 3 speed. But everything is LARGER, of course.
And not available from the usual Model A parts houses.
Joe K
Fullraceflathead
Well-known member
AA 4 speed parts are becoming scare now.
Fullraceflathead
Well-known member
I believe the internal gears and parts are the same all the way up into the early 50s.
Joe K
Well-known member
Similar but not exact?
For instance. The 28-48 Chassis "Green Book" page 291 shows truck transmission blow-outs for the various Ford trucks in this time range. They all reference a cluster gear "7113"
The next page (292) shows a chart showing the various "7113" gears - and some specific dimensions/tooth counts for the gears.
A-7113 is 5 inch overall length (Car)
B-7113 is 6.59 inch overall length (Car)
BB-7113-A is 6.68 inch overall length (BB Truck)
The tooth counts varied similarly if not more so. The chart indicates with asterisks any helical gear as shown in the pix. The blow-outs on page 291 appear accurately drawn including helix gears.
P. 312: The 7111 countershaft shaft varied at least three times during this period. The OAL of the Model A shaft is not shown. B-7111 was 8-9/32 BB-7111 was 9.160"
I have to keep in mind that the "Green Book" catalogs both Ford Cars as well as Ford Trucks.
So yes, it appears the "BB transmission format" was kept all the way up through 1948. Possibly even with the transition to V8.
The price of the "Green Book" varies depending on the Ebay seller. Some get BIG BUCKS for the book, others sell more reasonably - so shop around. Check variations on the title: "Green Book 1928-1948" "Chassis Parts and Accessories - 28-48" etc. Also check Abebooks and others.
P. 293 Interestingly, the AA-7006-A case assembly (i.e. the original Model AA case) is shown but indicated NOT SUPPLIED. Directly below it is shown the BB-7006 case for years 32-34 and below this the 59T-7006 case for years 32-47. This latter likely the "upgraded" case to correct the "design defect" of the original Model AA cases as identified by Vince Falter at Fordgarage.com Along with the 59T case is shown various bolts, lockwashers, and a flat washer to do a case substitution without the early case defect.
Later may be better in AA transmission cases.
Joe K
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