Aison Kickdown Dead Pedal Question

[MJWenrich]

In another thread it was mentioned that sixth gear should hold and pull without shifting down unless encountering a really steep hill or pulling heavy. I mentioned that my Aison has always dropped to fifth when encountering even the slightest hill. The searching is annoying to say the least. So when pulling slightly uphill for long stretches, I drop to fifth using the switch on the stalk. Or the tow/haul. But that made me wonder if the transmission is doing what it should. I would prefer it to pull better in sixth to get the advantage of the 342 gears and mileage. Someone on the forum said I may have something wrong with the trans. and that got me to thinking that it might also be related to the dead pedal problem. The three to four second lag in downshifting may be related?

So...I am asking here if those with 342 gears and an Aison have the same issue(s) as I do. Or maybe it's a separate issue but I have not heard before that the Aison tended to drop out of overdrive at the slightest pull. Appreciate those with the same set up weighing in with your experience. If it turns out that they are related then we might compare build dates and locations to see if we have similar programming times. Getting nothing from RAM on this issue, several reflashes or opening a STAR case has done nothing to remedy my problem.

Mike

 

[pfd66]

At 65 mine downshifts on slight hills, at 70 stays in sixth gear. Always has, even with no load in the truck. Only really notice it with cruise control on.
Have a 2014 SRW Mega with the Aisin.

 

[Bob4x4]

An auto trans that did not downshift would give me more concern.Holding 6th gear under load when it should be in 5th will cause more wear and tear and decreased fuel mileage

 

[MRinehart]

yep mine does the same thing.i feel the trucks should of had a minimum 3.73

 

[AH64ID]

An auto trans that did not downshift would give me more concern.Holding 6th gear under load when it should be in 5th will cause more wear and tear and decreased fuel mileage

Exactly. Keeping it in 6th means the engine has to work a lot harder to get the torque to the wheels. The 3.42s are why this happens easily so your being effected by them and not taking advantage of them.

 

[RVTRKN]

That's the big disadvantage to 3:42 rear ends. It's great for flat unloaded driving, but put a load and slight grades its poor mpg and constant downshifting needed or you keep it in the best gear like I do. I keep my 2014 truck at 1500 rpm regardless of gear until I'm at cruising speed. But when even with a slight incline will cause my mpg to drop and I have to downshift. But I do have the 68rfe.

 

[Hoefler]

I have found on my truck, 2014 with 3.73 and Aisin, 72 mph is where the engine is the happiest. I have noticed that it likes to cruise at 1,800-2,000 rpms, will downshift at 1,600. Pulling our 40' fifth wheel, I will get 9.4-9.6 mpg, and downshifting is minimal. That was with only 3,000 mile on the odometer. I will have over 20,000 mile on it when we take our next long trip, I'll bet my mileage will be better. The best I ever had with my 2010 with 4.10's, was 10 mpg, but usually averaged 9.2-9.4.

 

[NIsaacs]

An auto trans that did not downshift would give me more concern.Holding 6th gear under load when it should be in 5th will cause more wear and tear and decreased fuel mileage

I agree, that's what automatics do, they down shift based on input.

Using 0.63 6th gear x 3.42 rear axle @ 70 mph (32"tire) your engine is turning 1580rpm, the slightest movement of your right foot will cause a down shift. The engine is at the bottom of the barrel.

Using 5th gear 0.77 x 3.42 rear axle @ 70 mph you are now at 1933 rpm or in the sweet spot.

Nick

 

[MJWenrich]

Thanks to all for the input and I failed to mention that mine does not do the searching when I am above 70MPH. Sounds consistent with others here. It all makes sense but I wanted to make sure it isn't related to the dead pedal. In 5th it responds well to input but the dead area is still there for passing, but less of a lag. Because I live in the hills I am limited to 55MPH & CHP will let us have 62 MPH. So the sweet spot is not there in 6th. I will continue to use 5th coming uphill and disregard the concern.

 

[Cummins12V98]

When I had my 11 HO Dually with 3:42's I towed a combined 30K. I found after trial and error that I would get the best mileage in 5th gear. Just so happens the RPM's in 5th with the 3:42's I had were the same as if I had 4:10's in 6th. So the reality is a truck with 3:42's has the same gearing with a extra gear compared to a 4:10 truck. The only real disadvantage to the 3:42's is launching, you need to take it easy until the load gets rolling then it's game on!

Everyone claimed the "sky was falling" when I talked about my dually with 3:42's towing a combined 28-30K. It actually did very well!