Community Forums

Scooter · 02-16-2025, 04:10 PM

Our 2003 Dolphin has not moved more than 100 feet in 2 years. Need to drive to a shop tomorrow for repairs and I anticipate Dolphin will not run above 3000 rpm (30 mph) as I tried today for an hour going up and back in our short driveway....going thru all the gears....into reverse back to the starting point...... and rinse and repeat.

Any tips on how to get the Allison back to normal ? Don't want to drive to shop with commuters honking me off the road....

Do the Allison and 8.1L talk to each other and figure this out ? I recall maybe, 10 years ago that this popped up and I drove 5-10 miles in LIMP...pulled over, waited 15 minutes. Started up again and all was OK

Any and all comments much appreciated.

Skip426 · 02-16-2025, 09:32 PM

The 1000 series of your vintage ( when used in GM trucks ) was prone to water intrusion issues with the NSBU ( Neutral Start Back Up ) switch on the side of the transmission, and would only have second gear when any forward gear was selected. ( Default )

When trying to go forward do you think the transmission is in first gear ?

Arch Hoagland · 02-16-2025, 09:36 PM

Has the transmission fluid and spin on filter been changed regularly?

Scooter · 02-16-2025, 10:49 PM

Hi Skip.....it has been housed in a metal shed for years. Today it seemed trans was in 1st.....2nd or 3rd as selected. Just no more than 3000 rpm.

Scooter · 02-16-2025, 10:51 PM

Hi Arch....no fluid or filter in 10 years. Only driven 10,000 miles over that time span.

H Hill · 02-16-2025, 10:54 PM

The allisons are strange trans and will not shift until you hit certain MPH requirements, one probably not reached in your short driveway. (such as, it won't shift into 5th until you're above 55mph).

The 3,000 rpm limit is an engine issue (limp) not a trans issue. Maybe fuel pump, maybe injectors. Could be several things at once.

IF the gear symbol isn't illuminated on the dash (upper left side), I'd say you won't have any issues once you exercise it by going down the road.... aside from issues from not changing fluids in 10 years.

I'd be more worried about the tires if it has been setting as long as you say.

Scooter · 02-17-2025, 07:28 AM

Yes, the tires are next up on the list. This will be a slow speed trip to shop. This shop visit is about the non-starting Onan 5500 efi generator.

I need a visit elsewhere for the engine/transmission possibilities. Thank you

Scooter · 02-17-2025, 11:44 AM

OK, trip to shop went well. RPM leveled out at 1800 @ 55 mph. Just like the old days.

Thanks for your comments.

Arch Hoagland · 02-17-2025, 11:57 AM

Wait a minute something is wrong here. You had an appointment at the shop today and they actually fixed it and gave back to you the same day???

It's supposed to sit there a couple weeks and then they order parts, etc. You need to find a new shop...lol

Flyer15015 · 02-17-2025, 12:08 PM

Scooter,
On my '04 PA (8.1 / allison1K) the shift point under "normal" driving is
3200 RPM. I can play with the gas pedal and get her to shift a bit early if going down hill with no load. 4th to 5th see sawing is very common when in a head wind and it doesn't take much of a hill to have her drop into 4th.

Mike in Colorado