Bought an 03 w/ 32,000 miles, crew cab LS-D/A

Oil pressure reads 100-120 normal city driving, and we cannot turn off the overdrive on the allison.

Truck runs strong and shows no other signs, our other d-max has oil pressure of 60-- and 80 when cold--never seen 120??

What would cause this??


LT Construction Co.

short?

short?
I hope that you meant to say "Short in the guage wiring?" Maybe. Most electric oil pressure guages work by sending a 12 volt (just guess) signal through the guage to the sending switch, where pressure to the switch regualtes how much ground the circut gets. So if you have a short in that circut you will get a max reading.

Or something like that.

John

could be a bad oil pressure sending unit ?

Sounds like it is the instrument cluster panel.
You said it had 32,000 miles, it should be covered under warranty.
I had to have mine replaced at 1,000 miles.

I don't believe there is an overdrive disable button on the 03. That feature I believe came on the 05.

My 03' has the overdrive disable button....02 didn't.

my 03 has OD disable.

Press and hold the button in the end of the shifter for about 3 seconds.

the older LB7 Duramax's oil pressure reads higher than the LLY models.. my buddy has an 02 or 03 and his reads that high. Mine reads low just like the other newer motors.

as for the OD disable. just shift out of D and into 3.. its the same as drive, but no OD.

you might pose these questions in the LB7 forum since that is what you have.
good luck

yeah john i meant a short as in an electrical short.

Look carefully at the gauge on the trucks, the earlier trucks are calibrated different. The numbers/sweep are different.

OD L/O can be installed easily on pre 03 trucks, its already there on 03+ trucks. Shifting to D3 will give you only 1st, 2nd, and third. You will loose 4th.

And 5th.