M109 Self propelled gun info needed

[David Herbert]

Possibly because although the original T55 engine is excellent, the transmission isn't. The whole thing is just plain crude. The service clutch is a metal to metal dry multiplate clutch which never fully disengages. If you are stationary, in gear for more than ten seconds the plates get hot, warp and engage themselves. Primary gearbox is simply crude, fan drive is unbelievably noisy, particularly at idle when you can hear the backlash in the gear train banging back and fourth. It also has clutch and brake steering which is just dangerous at the speeds that it is capable of driving. Note that all T55 / T62 in news programs have the fenders rounded off on all four corners, there is a reason for that !

Having said that, it is I believe the worlds most prolific tank family so someone loves them and we must remember that they were built for fighting in wide open spaces, not for the semi urban environment that western armour finds itself in.

David

[jdmcm]

Malcolm

we came across one, T-54, that has been de-milled by cutting out all the engine bay fittings, all that is left is the steering clutches/brakes attached to the final drives. As everything is worth saving, this seemed like a way to make a very functional, easily maintained and arguably better running tank, with parts available anywhere in North America. When we got the, what I call M109 pack for ease of description, ...we had thought about it for our Type 69, but that tank had such an fascinating story/history we decided best to keep it as original so we sourced a couple decent motors for it and left it how it was built.

John

[rob love]

When I check the parts manual for the ARV, the transmission pack is referred to as "M109/M578", so perhaps it is not much more than a change of the flanges. It is going back quite a while but I remember some differences in the generator or cooling systems between the two.

[Malcolm Towrie]

On the attachment in post 39, what is the "throttle shaft" for on the tranny? Engine load input?
Malcolm

[rob love]

Possibly similar to the kickdown cable on many transmissions. It might keep the transmission in the lower gear when under high load/maximum throttle, or might kick down the gear under similar circumstance.

[David Herbert]

Or it might be that it is part of the throttle linkage to the engine and from the pedal.

David

[rob love]

According to the online manual I referred to earlier, the throttle lever acts on the throttle valve and the throttle regulator valve.