1st to 2nd Gear Shift

[luckymick]

Have any of you experienced this:

When accelerating (say from a stop light), my first gear will pull through 2200 rpm's. The transmission will then shift in to second. The indicator shows the 1st to 2nd shift, but watching the tach (and of course feeling it by the seat-of-your pants) I see the rpm's go from 2200, to 1700, hold, and then to 1400 as the shift completes.

All my other shift points happen like a normal transmission, firm, smooth, switch from one gear to another. This anomaly only happens from 1st to 2nd under acceleration; deceleration all gear transitions shift smoothly.

Any ideas?

Thanks,

Mike

[W8RLM]

You may be feeling the first to second shift - 2200 to 1700 rpm and the indicator from 1st to 2nd, then the torque converter locks up which would be the shift from 1700 to 1400 RPM. The transmission is still in second gear at that point.

W8RLM - Bob

[luckymick]

W8RLM,

Thanks for the quick reply!

Is this something I should worry about? Should I have the local Allison dealer look at it? Simple adjustment or would this be a warranty item (transmission is 48 months old this July).

Appreciate your insights!

Mike

[jimkate]

My coach has 140,000 miles on it. The transmission has always shifted from first to second exactly the same way you describe that your transmission shifts. I used to worry about it, then I stopped worrying about it.

[JimM68]

I posted that exact same question a few weeks ago, and was told they all do that so don't worry about it. So I don't.

[alvinc]

I can understand the confusion because most all automobile automatic transmissions do not lock the torque converter until after the highest gear. Allison decided that it was more economic to lock the TC (Torque Converter) after the 2nd gear.

Also, If you pay attention to the shifts you can detect the TC lock up during the shifts in the higher gears, it is very subtle. Say for a shift from 3rd to 4th, the TC will unlock as the shift occurs, then re-lock immediately after. If the TC remained locked during the shift, the shift would be harsh.

[luckymick]

Thank you all for your replies. I know things can get expensive quick in when something goes wrong in the engine compartment. Want to make sure I'm keep up with required maintenance and having all the warranty items taken care of in my last year of warranty!

Appreciate the insights - like Jimkate said: I'll stop worrying about it!

Thanks again!

Mike