kt_Engineer

Yes. The TM transmissions are no longer available.

Hopefully this will help. Please be aware this is a old datasheet. The T306G, TM308, TM309, TM308M & TM309M are no longer available. The T310 is good upto 1860 lb-ft and there is a new T310ME21 that is good upto 2100 lb-ft.

I can provide all ratios if you are interested in a specific transmission. I can post all ratios for all available transmissions in a tabular format if required.

MackMaxiTorqueEST300Trans1.pdf

You need to calculate the desired startability index based on Clutch Engagement Torque, Tire Revs/mile, overall gear ratio (transmission start gear x axle ratio) and GCW/GVW. For a typical highway truck you want to have startability to be no lower than 16% to be on safe side but if you are going to drive turnpike only (<3% grades) majority of the time, Eaton suggests a startability of 12%. I have seen one customer happy with a 10.5% startability recently.

If it is a vocational truck (especially a garbage hauler) the minimum suggested startability is 25% which would require a deep axle ratio.

Yes. T313LR is same as T318LR as far as transmission goes. The only difference is the shift knob and pneumatic plumbing which prevents the high-split from engaging for T313LR. If you ever want to convert it into a T318LR all you need is to buy and shift knob, pneumatic lines and change the range/air valve for locking pin.

Mack Axles do have a Inter-Wheel Power Divider (IWPD)/Limited-Slip differential feature as an OPTION. This is unique feature not available on Meritor or Dana axles (though some After-Market solutions are available which if used will void axle warranty). IWPD works very similar to Inter-Axle Power-Divider with peanuts/wedges and CAM mechanism. The Bullgear/final Helical gear drives the cage which when spinning will force the peanuts to move up and down which in turn will spin the outer cam and inner cam. The outercam drives the left side axle shaft and inner cam drives the right side drive shaft. The IWPD will automatically torque differentiate when it senses one of the wheels spinning. The CAM mechanism will allow the non-slipping wheel to slowdown and transmits 3 times the torque to it. IWPD can work at speeds exceeding 25MPH unlike the diff. lock feature (which gets kicked out by VECU above 25MPH due to vehicle safety concerns). IWPD is available on CRD150/151, 125/126, 202/203 (previously was available on CRD95/96 carrier series too but currently is not) whereas Diff. Lock became available only with introduction of CRD150/151 & CRD125/126.

IWPD does NOT have a lock-out feature like the Inter-Power Divider Lock-out (PDLO) optional feature. You can order a truck with PDLO and IWPD or PDLO and Diff. Lock but not both. The standard Mack axle offering does not have a PDLO or a IWPD or Diff. Lock. You will only get Inter-Axle Power-Divider (with out Lock-out) and a standard gear differential between the wheels.

The attachment can help explain IAPD and IWPD in detail.

PowerDivider.pdf

T310MLR has starting gear ratio of 27.31:1 and is a pretty popular Mack transmission. You can run side mounted PTO's in stationary mode if you pick the range neutralize feature. The other option you might want to consider is T313LR (13 forward speeds and 3 Reverse). T313LR does not have a deep crawler gear like T310MLR but has starting gear ratio is 16.42:1 and reverse starting gear is 23.98:1 (better than T310MLR reverse starting ratio of 23.96:1). You might want to cost compare and see which ones serves you better.