Allison Shift Points

[ImagineIF]

I have a 6 speed Allison transmission in a 42-foot Beaver and was wondering if shifting into 6th gear at about 60 to 65 mph was normal. Whether the transmission is in normal or economy mode, that the speed it shifts into 6th gear. This is at about 1700-1800rpm.

Normal? If not, what needs to be done?

Thanks,

[a k]

At 62 MPH mine runs about 1400 RPM with 4:33 rear end. 308-22R tires

[JLMunsil]

That seems high to me. I think mine shifts at about 55 to 58 mph. Different motor homes probably have different shift points depending on axle gearing. Call Allison they could tell you. Let us know what you find out.

[ImagineIF]

I just spoke to Allison and they said that there's a lot of variables, but that shifting in 6th at around 65mph doesn't seem unusual. He suggested, if in doubt or wanting to explore having the shift point adjusted to check with my local Allison authorized repair center.

AK, I assume your 62mph = 1400RPM is in 6th. That sounds the same with mine. After shifting into 6th at 65mph, it will stay there don't to about 60mph on level roads.

Other than wanting to save fuel at 55mph, I guess I'm not too concerned with the shift point.

[squeak]

mine shifts in about 65 I have a 500 cumm. I hate to tow in Cal. the speed limit is 55 towing WHO goes 55?

[a k]

Mine will run in 6th gear down below 55. It works off of a sliding pot with the throttle.

[ImagineIF]

A K, Are you saying yours will upshift into 6th at speeds below 55 or that it will stay in 6th down to speeds below 55? Although I said mine will stay in 6th down to 60, it probably will to 55 or less for a given grade. It certainly will not upshift until it's very close to 65.

I'll probably take mine to an Allisson shop and have them check it out and adjust it, it they think it's okay and possible to do so.

[a k]

Yes it will shift into high gear if it's not really loaded .

[Sixpack98]

Our Cummins ISL generally shifts into 6th at about 58 and will hold 6th until about 55 or 56. Our ISL starts to lug when much below 57 mph. I would imagine a heavier coach might keep the rpm up to avoid lugging the engine. If you have a Cat engine 60 to 65 may be where they want the 6th shift speed.

[squeak]

I will not lug mine good way to heat up the trans & temp and why

[Happycarz]

My 6th gear upshift is dead on 60mph, according to the Aladdin. And, like others mine will stay in down to around 55, depending on the load. ISL 400

[a k]

With a lockup converter you shouldn't overheat your trans

[lonestarace]

Our 1999 42' Monaco Executive w/450hp Cummins M11, HD4060 trans, 4.33 gear ratio, and 295x75-22.5 tires, shifts from 5th to 6th at 53 mph. This shift occurs at 1450 rpm and drops the rpm to 1300.

[Cat]

I've read in my Allison Manual (for the Allison 3000) that the allison has adaptive shifting. It learns how you drive and adjust the shift points to your driving style. If you gradually gain speed then it learns to shift early if you step harder it learns to shifts at higher rpm. (You can put it in to a learning mode so it learns faster--but that seemed to be a really involved process.) It also loooks at many other varibles ground speed -throttle position etc.