2018 Aisin shifting issue

[kthaxton]

Uhm yeah, higher rpm and lower gears are what can improve performance climbing a grade. It makes the engine's job easier.

And what do you mean not hold the grade as long? It's actually the exact opposite, 3.73's help the trans hold 5th gear longer before a downshift than with 3.42's.

Didja notice Ram rates 3.73's for higher capacities than 3.42's? There is a reason for that.

 

[Wiredawg]

Hi,
My 5500 is my second Cummins/Aisin truck. The info on the transmission says its adaptive, so it must adjust to driving style and load. The only time mine acts confused is when I'm in traffic doing rapid adjustments on the go pedal. I believe we're just fine as this transmission is matching awesome tq/hp, heavy trucks and loads, and rapidly changing conditions. You and your truck are learning each other.

Enjoy your truck and happy trails.

Ron

 

[Cummins12V98]

Uhm yeah, higher rpm and lower gears are what can improve performance climbing a grade. It makes the engine's job easier.

And what do you mean not hold the grade as long? It's actually the exact opposite, 3.73's help the trans hold 5th gear longer before a downshift than with 3.42's.

Didja notice Ram rates 3.73's for higher capacities than 3.42's? There is a reason for that.

I was thinking backwards.

Same difference a 4.10 will pull better than 3.73 in the same gear.

You are correct.

 

[gsbrockman]

I was thinking backwards.

Seems like a HUGE amount of your thinking has been backwards as of the last few days.

 

[TCDiesel]

There's much to be considered in Gearing, Cam design, TC Stall, Trans gearing, Turbo, tuning ,Tire size, SPEED, RPM VS Boost.

What's is your goal? Mileage, Power, Speed.

3.42 will gain mileage at High speeds truck alone, Same speed towing 3.42 VS 4.10 the engine runs at higher RPMs with less Boost(4.10) , 3.42 lower RPMs Higher Boost, More air more Fuel , this is were the Turbo spec's are critical , its need to produce more air at lower RPMs to equal the Power More RPMs create 4.10.

The Turbo (OEM) does a good job at singing along truck alone, it suffers at lowers RPMs that the 3.42 speeds create, so you need to drop to 5 when pulling to gain HP to pull that hill when towing. You leave that truck in 6 at 14-1500 RPMS climbing hills at High 20-28 PSI boost and your cylinder pressures and temps are much higher than 19-2100 RPMS, That heat will effect on the life of the head and Valves, Yes you are spinning the rotating mass fast so over the life of the engine that will effect wear, its a very fine line and will take knowledge and understanding couple with a good SOP and upgraded foot and some windshield time to know were the sweet spot of your setup is.

If Your a weekend/week day Rambo warrior and don't give a crap about Mileage, wear and safety disregard this post and carry on.

Yep ,I will wave at Ya when your in the Hammer lane and drive by Me ,and wave at Ya, again at the Pump and ditch as I drive by.

 

[kthaxton]

Same difference a 4.10 will pull better than 3.73 in the same gear.

Absolutely.
For moving a load:
3.42 Good
3.73 Better
4.10 Best

 

[Sleeping Giant]

Hi,
My 5500 is my second Cummins/Aisin truck. The info on the transmission says its adaptive, so it must adjust to driving style and load. The only time mine acts confused is when I'm in traffic doing rapid adjustments on the go pedal. I believe we're just fine as this transmission is matching awesome tq/hp, heavy trucks and loads, and rapidly changing conditions. You and your truck are learning each other.

Enjoy your truck and happy trails.

Ron

Thanks Ron! A few days and about 500 miles since my original post and I can tell it's already different (a lot better).

 

[Cummins12V98]

Absolutely.
For moving a load:
3.42 Good
3.73 Better
4.10 Best

Moving a load as getting off the line for sure.

Ok now that I have cleared my skull. Towing at 60 with 3.42's in 5th will pull the same as 4.10's in 6th, basically same RPM around 1,750. But what's interesting is once you drop a gear things can change and NOT always benefiting the 4.10's. It all depends on grade. I logged speeds with my 3.42's and 4.10's sometimes the 4.10 will smoke the 3.42's but not always.

 

[gsbrockman]

Absolutely.
For moving a load:
3.42 Good
3.73 Better
4.10 Best

The above sounds verrrrrrrrry familiar.