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Old 06-11-2009, 08:09 AM
madbomber madbomber is offline
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hydraulic oil in derby cars....you must replace all the plastic components internally w metal components or they will melt. the hyd oil takes longer to break down/heat up, but when it does, it is very hard to cool down. my guys who do run hyd i usually run water/ice coolers or big air to air hydraulic coolers out of skid loaders. you lose about 200rpm stall speed as well.

other things...leave out the center seal on the forward drum.....drill the rev port on the spacer plate just a bit, but not bigger than 7/64th's.

for 1st/rev only.....plug the direct/3rd gear port on the center support and remove the center seal of the direct clutch. esencially do the same thing as most people do to improve the 3rd gear shift except backwards. although it sounds pointless it actually slows the apply down slightly to keep the direct drum backing plate in one piece longer. the constant back and forth shifting just tears them right out...taking out reverse.

.005" of clearance per clutch disc works well...leave out the wavy steels they will just break. use an aluminum piston in the direct drum.

you must replace the 3rd gear accumulator w aluminum if it is plastic. when it breaks....and it will....you lose reverse.

there are numerous other things you can do for a derby tranny, especially for low 1-reverse only operation. pm me if you would like more details. thanx

Last edited by madbomber; 06-11-2009 at 08:22 AM.
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