Prebuy checklist?

Nope just the 4700RDS with 4.10s out back. This thing pulls with no issues and I can't see a use for the auxiliary in my setup. I've gotten it moving on some pretty good grades even at 210K+.

 

I am thinking of going that way on my next truck but running either a 4 spd or the 3 spd

how is it getting up to speed heavy?

anything you don’t like about it?

 

I would never want to go back to a manual for heavy haul after having this trans.

The only real downside is they are torque limited to 1850.

Even loaded over 200K I can accelerate faster than most loaded dry vans I come across.

The biggest advantage to the Allison over a manual is the smoothness. Most of the time when doing slow right maneuvering I just rest my foot on the brake to control speed. No trying to lightly slip a clutch.

When you are accelerating you have full power shifting. There isn't that momentary loss of power you get while shifting the manual. Even at 200K it can easily grab gears going up hill from a dead stop. You can't actually feel it shift gears. Can only tell by engine noise and the tach dropping.

On mine 1st gear has to be manually shifted and is only used if you want to start on a hill while loaded heavy. The Drive position starts at 2nd. I just run 1st to 5mph and then knock the shifter into Drive at 5mph. 1st tops out at 8mph. If I wait until I hit the top it slams hard into 2nd. Doesn't hurt anything but sounds terrible so I try not to do it if I can.

Once in 2nd it runs the gear once with the torque converter unlocked and slipping at 2K rpm. Around 13mph it locks and stays in 2nd. At about 17mph it unlock the torque converter and slips at 2K until 20mph then locks until 24mph. 4th-7th are always locked torque converter. 4th is from 25-43MPH. 5th is 43-58mph. 6th is 58-65mph. 7th is 65-95mph.

With reverse there's a high and low. High is pretty standard reverse and can go about 20mph. Low range is I think around 17:1. It wasn't enabled on my truck for some reason when we got it. Had to have it unlocked in the software. First time I shifted to it I wasn't expecting how strong it would be. Wasn't holding the brakes hard enough and it pushed right through them and stared pushing my step deck backwards with the brakes locked on it. Now I make sure my foot is all the way down on that pedal before I bump the shifter to low range.

Another major advantage is having the engine brake, transmission, and cruise control all talking to each other. If I'm braking the truck will always downshift to keep the RPM as high as possible for max engine braking.

I was talking to the owner of a company I borrowed a trailer from today and he runs all 18s with 2/4 so aux. He looked into ordering the Allison with the aux and I guess they have problems because they can't talk to each other so it doesn't really work.

The guy we bought my trailer from runs the same engine/trans as me on his last 3 trucks over the last 7-8 years with no issues. He has 4.30 gears though. He runs a 13 pulling Nacelles most of the time.

The Allison really is nice to free up a hand to hold the radio and just give me once less thing to have to think about while trying to keep track of the trailer.

 

thanks for the info

When I built this truck, the engineers wanted me to go super deep like 5.63 and then back it up with an auxiliary but none could explain how I was supposed to run it.
I think if I did mate the 2 together it would just a simple range change from 1:1 to 1.27:1 underdrive likely.

mine of the things that keeps me from going really heavy is concern about getting started in a very steep hill.

anyway food for thought - you have no issues at 210k

I have about a year to think this over

 

I will say that if I have to start on a hill I'm usually stuck in 1st gear running 8mph all the way up. Only reason I won't try to run it faster in 2nd is trans temp. Slipping the torque converter dumps heat into the trans so fast that it can't keep up with the cooler. Made even worse by the low speed meaning lack of air. I will usually try to get it to second but if it can't get to lockup speed within a minute I have to back out into 1st to protect the fluid/trans.

I'm think of going to 4.30s on the next truck to maybe help the trans get into higher gears on hills.

 

Trust me I was pulling the 10% grade in 1st when I went to BC but that was because I did not want to risk a shift

do you run a trans brake as well?

do you just lock it in the gear you want when you are going down a long grade?

 

No trans brake. They won't approve trans brake and engine brakes at the same time. Supposedly there's real risk of that snapping a drive shaft. Too much braking torque. At least according to the engineers.

Some times I will lock it in if it keeps trying to shift but rarely do I have to. The Cummins engine brake is so strong on full power that it can usually slow me down on down slopes no matter how heavy I am. I actually have to rest my foot on the throttle at times to kill the engine brake so it doesn't slow me down too much.

5th gear is direct and that's usually what it goes for on downhills. It will only run the engine brake down to 4th gear automatically. If I want the engine brake in 3-1 I have to bump it over to manual mode and force it.

I wouldn't even hesitate to hit that 10% grade from a dead stop with this truck. I'd be more worried about spinning out than the trans not being able to get it going.

90% of the time I drive the truck with my right thumb on the cruise buttons on the wheel. Once I go over 28mph I don't touch the pedals until I need to stop or hit a hill that pulls me down under 28.

The engine brake kicks in at 4mph over cruise speed. It down shifts to 5th at 6mph over speed. That's usually enough.

 

@Rontonio with the 18/aux how does that work? I know the aux is an auto but does it shift a lot or is it something where you pretty much chose a gear depending on conditions and leave it there?

 

no it is totally manual.

my aux has an overdrive direct 1st underdrive - 2nd under drive


So the way I do it is in 1st under in the aux I run 1-5 (usually rarely split the bottom side) then shift to direct and split the top side of the. Ok all the way to 18

I only use the 2 Nd under drive on a jobsite that I need to creep around.

I rarely use the over drive in aux box because the gear whine bothers me and I tend to only run 60-62 anyway,

The good news is I can shift the aux up or down without stopping - a 2 spd aux usually has to stop to downshift.

I run an 1850 torque motor as they would not build the aux with the 2050 motor.

it is really a lot more intuitive than it sounds. You just shift the aux when it feels right. From direct to under is about 500 rpm drop - from under to deep under is much bigger and I don’t do it.

Having said all that I really like it and it pulls very well and steady. Just don’t try to change the main and the aux at the same time - or you get to stop and try again (or so I am told not that I would ever have done that once or three times)

 

Do you have a second stick for that?