02rexwi said,
JNHEscher said:
All depends on the t-case functions. I'm going entirely off the AT page at the moment -
https://www.axletech.com/en/products/transfer-cases
Have to figure out the coupling/decoupling stuff and how the torque split works. They mention declutching which makes me think the split works with something like a limited slip diff. Going to go through the 600 and 750 manuals. The 800 doesn't show a link for a manual. 1224 might be way more than I need.
If I have to, a t-case for each axle. If the t-cases can be shifted to work like a twin-shifter t-case like rock crawlers are built, I think I could run two t-cases - one between the two rear axles and another to transfer to power to the front axle (or both front axles if I get that crazy lol). I'll lay out dimensions once I know which t-cases would work and then figure out d-shaft stuff.
Edit: I sent another email to Inland Truck Parts asking about the Allison torque converter ratio. I've looked for an answer on this before and info was kind of inconclusive. My guesses were that the ratio is either the torque multiplication or some assembly in it that is a gearing step-down.
Playing around on grimmjeeper - I put in all the trans ratios, tire height and current diff ratio. Remembering the drive back through small-town-America, I was holding the throttle at around 80% on the highways, keeping mid 60's on the speedo. Omitting the 1.50:1 converter ratio from the calculator, 80% of a governed 2100 RPM is pretty much dead on. Multiplying the diff ratio by the converter ratio throws the highway speed off quite a bit, so this points to the converter ratio just being a factor of torque multiplication.
And now Axletech. 5.64:1 overall ratio on the narrow axle diffs and 0.80:1 highest overdriven high gear ratio in the T800 t-case drops the highway speed to 47mph at 1750rpm versus the current 64mph. I'd have to know if I can change out the planetary hub gears to better suit the highway. This is what I deemed to be a pain in ass and what the attraction to electric drive was when I was looking this over throughout last winter. Axletech does show quite a few ratios for the 4000's. I'm just not sure where to find them unless I call up Axletech and I suspect that will end up costing more than the axles themselves.
And lastly for the night, I'm wondering about the torque distribution in the t-cases. Looks like some have the option of a planetary set. I'm guessing there's a viscous coupler in there to make the 33/67 split. Too tired to go over them any more tonight and I have to be up to drive in six hours. Here's the Axletech pdf -
https://www.axletech.com/at-admin/re...etterweb-3.pdf
I'm going to try to answer the questions I think you're asking, but it's unclear to me exactly what you're asking.
Question: What is the torque converter ratio
Answer: The published "torque converter ratio" you're asking about is probably the stall ratio. This is the ratio at which the torque from the engine is multiplied when the converter is stalled (such as going up a steep grade). There is no gearing involved in this ratio, it is simply a way of the torque converter multiplying the torque of the engine.
Question: How to get power to every axle in a 6x6 setup
Answer: By far the most conventional driveline layout involves an engine bolted to a transmission. The transmission connected to a transfer case by a driveline.
This transfer case usually has some sort of differential for on-road operation. The "center differential" in the transfer case can be locked out in some models to lock the output of the front and rear output together.
The torque split of the differential in most heavy duty transfer cases is made by either a 50/50 bevel gear differential (like an open differential in a truck), or by a planetary gearset for torque proportioning between the two output shafts; with a planetary differential you can get varying amounts of torque proportioning based on the size of the gears, but typically ratios are around 33/66 split. In the case of a 6x6 truck with a transfer case between the first and second axle the front axle would get 33% torque and the rear two axles would get 66% of the torque coming out of the transfer case, then the front tandem axle in the rear would have a 50/50 bevel gear differential which splits torque equally between the two rear tandem axles. In theory that means every axle gets equal torque.
After the transfer case there is an output to one or more front axles and one or more rear axles. If the output is going to more than 1 axle in either direction the axle will typically have a differential in it which allows differential speed to the next axle in line. In most cases this differential can be locked. The two differential lock actuators on a "tandem axle" are for the two internal differentials. One splits the output from the axle it's in and the next axle in line. The other actuator is for the side-to-side differential lock.
