Info on Allison 3000 Tranny

[Jack1234]

Greeting

We are new to large rig RVing, but are currently full-timing. Have been on the road since Mar.01 & are still working out the various systems on our Rexhall 38DP.

I would appreciate it if I could get some comments on the practical use of an Allison 3000. I understand R & N & that D..... puts me into auto go! My question is "what" practical application is there for the (1) Mode button .... What happens if I push it? (2) what do the up/down arrows control?

Anyway....greatly appreciate some simple practical advice on how this tranny works (nothing too technical needed)

Cheers

[Triker56]

Mode Button engaged when light is on. It lets the transmission shift at lower RPM to each gear. It may pay with better MPG but hard to prove. Best to not use it in hilly country so trans. will downshift sooner to keep RPM up.

The up/down arrows are for manual downshifting the transmission from 6th to 1st. If in hilly country going up and transmission starts hunting between gears a manual downshift will stop that.

They are also used to check fluid level, trouble codes etc. Info in the manual.

Also on long climbs a manual downshift can help keep RPM's up for it to run cooler.

PDF 3000 Owners Manual Download and save.

Welcome to the forum.

[JimM68]

And on desents a manual downshift or two can help control your speed, useful when the engine brake would "control" it too much.

Also the Allison is smart. Regardless of what you tell it to do, it knows better than to do anything stupid, and it won't let the engine over rev.

[automch]

The Allison 3000 is a rugged long life transmission. It has the capability of meeting every need your RV puts to it. The up and down arrows allow for manually selecting a lower gear for long up hill or mountain pulls and for engine braking when descending the mountans.

The mode button is programable by Allison to set up different shift points for fuel economy or heavier loads. It can be set to only shift 1 through 4 gears for heavy traffic, then hit the mode button for 1 through 6. There are multiple ways it can be programmed, but know this every modified shift pattern has to be approved by the coach manufacturer and is costly! Allison will write the program then it is downloaded into your controller. It all depends on what your manufacturer asked for when they purchased it from Allison. BTW I was a certified Allison Tech approved to program their transmissions proir to my retirement.

[Mr_D]

Our first DSDP preselected 2nd when the e-brake was engaged, I had it changed to 4th and wished ever after that I had left it alone!
The transmission programming won't let it do anything that harms either the engine or trans. The mode button merely preselects a gear and tells it to downshift ASAP without harming anything. You can override the preselect and again the trans won't do anything to harm the engine or trans. You could even select "R" (no "R" doesn't mean "Race") at 70 mph and no harm will be done.
Most RV manufacturers have the Allison programmed to change the shifts about 200 rpm when under heavy throttle allowing the trans to pull down to torque peak before downshifting. Under most cruising conditions pressing the mode button won't affect fuel mileage much. It will make a difference in some hilly conditions but don't expect much change even then.
The up/down buttons change the gear preselected, you can down arrow to 1st at 70 and won't harm anything because the trans knows that will harm it or the engine.
The older shift pads had two windows, on was the preselect gear and the other was what you were actually in. The new ones only have one and that's just the gear you preselected.

[Mr_D]

Quote:

Originally Posted by JimM68 And on descents a manual downshift or two can help control your speed, useful when the engine brake would "control" it too much. Also the Allison is smart. Regardless of what you tell it to do, it knows better than to do anything stupid, and it won't let the engine over rev.

If the trans control is too much you want to upshift rather than downshift.

[Steve Ownby]

Make sure you keep up with fluid and filter changes. If you are not using Transynd, you should consider it.

[hzjcm8]

Quote:

Originally Posted by Steve Ownby Make sure you keep up with fluid and filter changes. If you are not using Transynd, you should consider it.

And ...... you should do oil analysis on your engine and transmission. It pays for itself many times over.