Just saw a Military Channel show on restoring military tanks, an episode on the 1943 light armor M24 Chaffee.
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I knew from my studying the history of GM's Dual Range Hydramatic transmission (that we all know and love as the Hydro made famous in 60s gasser drag racing by B&M, Hydro Motive, among dozens of other tranny shops) that they cut their teeth in service in military tanks. That is why they were/are so stinking strong right out of the box.
Sure enough the WHOLE EPISODE on the M24 was about the Hydramatic tranny! Seems the front seal started leaking. They had to dis-assemble much of the tank to reach the seal which was the original leather lip one that was cracked and rusted. They searched all over the country for a replacement finding it just in time to ready the tank for a 4th of July parade (tired plot of all the reality shows - time crunch).
Front seals have always been a problem for the Hydro. The auto version we use in racing has the front pump held in the case with a couple of 1/4" bolts, and then only the edge of the bolt catches the edge of the pump to keep it from falling out. An O-ring does the sealing. In hi-po applications, the front of the case warps enough to allow fluid to pour out of the case. B&M's solution was to literally glue the bell housing to the front of the tranny, sealing the pump from leaking! They sold a two part adhesive along with the tranny and voided the warranty if you didn't glue the bell-housing on.
The tranny was actually used first in the 1941 light armour M3A1 Stewart
![Image]()
at the start of WWII but that tank was obsolete and an easy kill for the Germans, thus the creation of the M24. the Stuart was still useful for the duration of the war as a recon tank but not too good in battle.
I knew from my studying the history of GM's Dual Range Hydramatic transmission (that we all know and love as the Hydro made famous in 60s gasser drag racing by B&M, Hydro Motive, among dozens of other tranny shops) that they cut their teeth in service in military tanks. That is why they were/are so stinking strong right out of the box.
Sure enough the WHOLE EPISODE on the M24 was about the Hydramatic tranny! Seems the front seal started leaking. They had to dis-assemble much of the tank to reach the seal which was the original leather lip one that was cracked and rusted. They searched all over the country for a replacement finding it just in time to ready the tank for a 4th of July parade (tired plot of all the reality shows - time crunch).
Front seals have always been a problem for the Hydro. The auto version we use in racing has the front pump held in the case with a couple of 1/4" bolts, and then only the edge of the bolt catches the edge of the pump to keep it from falling out. An O-ring does the sealing. In hi-po applications, the front of the case warps enough to allow fluid to pour out of the case. B&M's solution was to literally glue the bell housing to the front of the tranny, sealing the pump from leaking! They sold a two part adhesive along with the tranny and voided the warranty if you didn't glue the bell-housing on.
The tranny was actually used first in the 1941 light armour M3A1 Stewart
at the start of WWII but that tank was obsolete and an easy kill for the Germans, thus the creation of the M24. the Stuart was still useful for the duration of the war as a recon tank but not too good in battle.
