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Auto shift transmission - Printable Version

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Auto shift transmission - Carter - 09-08-2022

My company has been switching to dd12 transmissions over the past couple years. Most drivers hated them but have come to prefer to drive them. We do short local hauls so it just makes driving more relaxing. What are other peoples thoughts on them, good and bad.


RE: Auto shift transmission - tree98 - 09-08-2022

An auto trans paired with really tall rear end ratio is a good way to get a short life out of your engine. It just beats the liners out of an ISX.

I guess the perk is you can be lazy and just smash the accelerator when the light turns green and not have to shift. Doesn't seem like a good trade off to me.


RE: Auto shift transmission - Carter - 09-08-2022

I’m afraid it is making me lazy! Funny thing is when I’m driving the auto I miss my old manual. When I’m driving my old manual I miss the auto.
If I owned the truck and was paying the bills I wouldn’t be lazy enough to spec an auto, couldn’t afford the repairs/downtime.


RE: Auto shift transmission - Rawze - 09-09-2022

An auto-a$itter is also much higher maint. costs over its lifetime + yields about 0.6 mpg less fuel economy vs a good driver, and shortens the life of the engine.

If is simply all-around a higher expense with no positive benefit above assisting someone handicapped, etc.. or that has a specific need for it.


BTW: Same thing with car trannies. Same issues. -= This is why all my vehicles are stick.


RE: Auto shift transmission - Snowfarmer - 09-11-2022

I'm another one that has to drive one of these things every day. I have driven most of the eaton autoshi$ers, the i-shift, and the detroit. The I-shift is the smartest and will shift the truck "OK" when loaded. All the others will not.... in my opinion they are horrible. I shift my detroit 12 speed manually all the time. The good thing about the detroit is that the paddle shifter works properly.... meaning you can quickly pull the paddle up twice or down twice and it will shift two speeds for you. You can do it quick or slow and it works great. The Eaton's.... they take some practice and personally I think they shift horribly. It's a huge dissapointment to drive one of these instead of a manual.

Most of these trucks also have tall rear gears making them downright painful to drive in my area. The truck I drive everyday has 3.08 rears.... loaded I'm at 103,000... and it's ALL northern new england mountains and hills. Terrible!!!!

I'd say about 80 percent of the other drivers have no idea about the torture we are putting these trucks through... or they just don't care I guess. They just say "we need bigger engines" and "this truck is gutless" ....I'm hoping to some day drive my own, spec'd the way I think it should be... according to the great stuff i have learned here from all of you folks!

Anyway just thought I'd share my experience with these things.... and my how much of a bummer it is to drive one. I could probably go one for another hour about these things and their ridiculousness but I'll stop!


RE: Auto shift transmission - Meanwhile - 09-12-2022

Repair experience with my Auto Shift

My truck has the Ultra Shift 10 speed in it. This truck has 3:55 gears and I run 22.5 low pros and I felt it did pretty good until… The end of July it started having some issues getting stuck in gear and the only way I could get it to come back was to find somewhere to stop, shut the engine off for a minute or so and let the transmission cycle. Sometimes it would take a few tries to get neutral back and get rid of the ** where the gear displays. The day came where the reset didn’t work. I shut the engine off and it wouldn’t restart, Insite said there was no transmission recognized basically, faults on the dash said the input and output sensors weren’t reading and Eatons Road Ranger program wouldn’t communicate with the transmission either. The first place we looked for issues was the wiring harness from the transmission to the firewall, all was well, the J1939 wires were fine and everything pointed to the brain that controls the transmission, the TECU. I decided that since we were replacing that unit I may as well do all the sensors too in hopes of not having to get back in there anytime soon. All the parts were put back in, wires neatly tied and Road Ranger connected without any issues. All tests passed until it came to the clutch adjustment and the clutch actuator failed. After a few phone calls, the theory came about that the TECU may have taken out a few sensors and the clutch actuator on its way out. Being there were roughly 590,000 miles on this truck we began to question the clutch also. There’s an inertia brake that mounts inside the bell housing, it was junk and the clutch wasn’t looking to good either which we kind of expected. The new TECU doesn’t function like the old one did, it wants to upshift at around 1600 rpms and downshift at 1100. I find myself putting it in the manual mode at 6th-7th gear and shifting the rest with the button. I’m going to look around soon to see if the settings can be changed as to where it shifts at. And yes, as Rawze said, the repairs do cost more.


RE: Auto shift transmission - Carter - 09-12-2022

I don’t have to infer the costs or downtime driving a company truck but my 2018 cascadia has been down for 5 months waiting for a cpc I couldn’t imagine being a one truck O/O and having to deal with that, it would bankrupt you faster than you could get the parts.