Steve we're usally around the 5.5 tonne mark when loaded for a trip.
The ratios in the Allison 1000 are1st.....3.10...........3.51
2nd....1.81...........1.90
3rd.....1.41...........1.44
4th.....1.00...........1.00
5th.....0.71...........0.74
6th.....0.61...........0.64(06-up models only)
Rev.....4.49...........5.09
Mine runs the LHS side ratios which has it sitting on 1850 rpm at 100kph with 37's
Yes the perkins adapter kit for the perkins ran an industrial stepped flywheel into which the adapter bolted then the flex plate plate bolted to what was essentially a piece in the middle which was the same as a chev 350 crankshaft.
The flywheel weighed around 50kg so there was plenty of dampening going on but a lot of inertia as well.
The adapter kit was designed originally for aircraft tugs in the US which were apparently manual back then to fit Th400 auto transmissions to enable them to get larger aircraft moving off the mark.
My using it for a vehicle was a first apparently and as a whole it worked well except the transmission couldn't handle the combination of the Perky's torque and the weight of the Oka.
I later fitted a Cummins 6bt and that took less than a few thousand k's to destroy the 4L80E's torque converter clutch. I was using a Compushift to control the transmission.
The 4l80E's torque converter clutch is about 120mm in diameter and about 12 mm wide in surface area so not much at all, combined with a typical hydraulic pressure of 30psi to clamp it isn't much at all.
The Allison is running much higher pressure, up well in excess of 100psi and the clutch surface area is about 10 times the 4l80E and much larger diameter so is well able to handle the torque from an intercooled 6bt
Bookmarks