Aisin Torque Converter Pattern

[TCollier]

When coasting down through the the gears without touching the brake pedal, what does the torque converter do. When does it engage/disengage. I feel a bump in the middle of 4th when letting my foot off the accelerator and just coasting and let the gears drop down. 6 to 5 is smooth, 5 to 4 is smooth, then bump, 4 th 3 is smooth and so on. It does not seem to do it in tow/haul and it will not do it if the brakes are even slightly applied. Dealership mechanic said it was normal for this transmission. I am pretty sure it has been this way since new.

 

[Hoefler]

With out T/H, it will free wheel when the rpm drops in the gear it is in. with T/H, it will down shift through all the gears as vehicle speed drops.

 

[Ram4Sam]

When coasting down through the the gears without touching the brake pedal, what does the torque converter do. When does it engage/disengage. I feel a bump in the middle of 4th when letting my foot off the accelerator and just coasting and let the gears drop down. 6 to 5 is smooth, 5 to 4 is smooth, then bump, 4 th 3 is smooth and so on. It does not seem to do it in tow/haul and it will not do it if the brakes are even slightly applied. Dealership mechanic said it was normal for this transmission. I am pretty sure it has been this way since new.

There is a paragraph in the owners manual about this. What you are feeling is a lockup clutch, to help mileage, that is locking and unlocking.

Sam

 

[NDanecker]

With out T/H, it will free wheel when the rpm drops in the gear it is in. with T/H, it will down shift through all the gears as vehicle speed drops.

Mine does not do this. Without T/H it will downshift every gear as you slow down. If you time it right and take it easy I use very little brakes when coming up to a turn, light or stop sign.

Weird....

 

[Ram4Sam]

With out T/H, it will free wheel when the rpm drops in the gear it is in. with T/H, it will down shift through all the gears as vehicle speed drops.

Neither of my Aisin trucks worked/work like this......out of T/H,mine downshifts all the way from 6th to 1st, you watch it drop each gear on the gear indicator, and feel the downshift and see it in the tachometer.

Sam

 

[gsbrockman]

Mine does not do this. Without T/H it will downshift every gear as you slow down. If you time it right and take it easy I use very little brakes when coming up to a turn, light or stop sign.

Weird....

My truck works exactly as you describe, NDanecker....and I even have the same configuration truck as Hoefler.

 

[TCollier]

It down shifts all the way down, whether it's in T/H or not and whether I touch the brakes or not. When it's not in T/H and when I don't touch the brakes is when I feel the engagement in the middle of 4th. The gear indicator shows the the current gear. BTW in T/H w/ full Exhaust Brake and I use the brakes it'll go from 6-5-3-2-1. It'll skip 4th. If I coast to a stop it'll drop down through each gear 6-5-4-3-2-1.

 

[TCollier]

I've really been paying attention to this the last few weeks. The jerk is also in the 6-5 drop too. I like to let the E/B do most of my slowing but now I'm starting to use a little brake to get through the these two rough spots. Started using auto exhaust brake instead of full too. This transmission will downshift for acceleration or increased load as smooth a silk and it runs up through the gears like a champ too. That's why this has so much of my attention. I know the manual says I may experience some rough feeling sometimes because of the torque converter clutch and so on but I can make this happen anytime I want. If everything else is so smooth, why these two lurches?
Do you guys with an Aisin have the same occurance? If this is just the way is, then I'm fine with that. I just don't want this to be the early signs of something that's going to finally break the day after my warranty runs out 7 years from now. The dealership mechanic said it's normal but they say a lot stuff is normal. I'd rather here it from y'all.

 

[sag2]

They don't break. They do shift like transmissions should, nice and crisp.

 

[Deleted member 995608]

They don't break. They do shift like transmissions should, nice and crisp.

Agreed. The only complaint I have is it shifts down into 2nd too early. Once it does go into 2nd, the RPM revs up and hangs a little too long, then abruptly shifts into 3rd.

 

[Cummins12V98]

They don't break. They do shift like transmissions should, nice and crisp.

That is exactly what Stan Gozzi said at MayMadness a couple years ago when asked about the Aisin.

It really is a pleasure to own a truck that performs great right out of the box!

 

[TCollier]

All other aspects of the way this transmission operates are great. The firmness, solid transitions let you know the beefiness of the equipment. Down shifting when accelerating or climbing a hill with the camper in tow is outstanding. Running up through the gears is great. But when coasting to slow down for a curve or a stop up ahead and the camper chucks forward at 30 mph because of a hard transition from 6 to 5 and then again with the torque converter engaging hard in 4th does not feel right considering every thing else is tuned so tight. If that's normal operation and everybody's Aisin does it then I'm OK with that. I don't have access to another Aisin equipped truck that I can drive around and try so I was asking for the experience here and appreciate all the feedback.