View Full Version : diesel auto tranny problem

sj-x 500
12-21-2006, 02:20 PM
k.. here's the deal. 01 dodge diesel 2500 with an auto, it will not hit 1st gear unless i punch it, or select 1 on the gear selector.

has anyone seen this before or have any ideas? there has to be someone on here with late model auto experience...

12-22-2006, 07:27 AM
sounds like its stuck in limp mode get it scaned.. might have a solonoid ishue or a band adjustment might work as well.

sj-x 500
12-22-2006, 09:37 AM
got it scanned... no codes present..

12-22-2006, 11:29 AM
damn larry you're up early

12-23-2006, 10:15 AM
mine a 98 and does the same thing i believe its the kick down and it does that on pourpose, i asked a mechanic at my shop and he said that it all has to do with the torque the truck has it just doesnt kik down if it doesnt have to. i dont think its a problem unless yer symptoms are different than mine were.good luck with it i now needa new tranny i cooked mine on the way down yesterday.

bc baja
12-24-2006, 11:25 PM
I work with robo at the trans shop.your truck likely has a bad govenor sol. & or a bad gov.transducor both are on the valve body in the pan .you can see this with a scanner in DATA .the following is the atra tech sheet we use for a high gear start :happy0045:
© 2000 ATRA. All Rights Reserved.

Occasionally wrong gear starts are caused by stuck shift valves; more often they’re
caused by high governor pressure.
Connect a 0–100 PSI pressure gauge to the governor port. Pressure should be 0 PSI at a
stop, and increase about 1 PSI for every 1 MPH of vehicle speed (12 PSI at 12 MPH,
45 PSI at 45 MPH, and so on). If governor pressure is good, the wrong gear start is cause
by a stuck shift valve. If governor pressure is high, the shift valves are okay.

1) Any transmission trouble code (very common)
2) Bad governor pressure control solenoid (very common)
3) Bad governor pressure transducer (very common)
4) Poor connections to the governor pressure solenoid and transducer (rare)
5) Bad computer (rare)

If it’s Friday night and you only have time for a guess, try replacing the governor pressure
solenoid and transducer. Replace both with brand new, OEM-quality replacement
© 2000 ATRA. All Rights Reserved.

When a trouble code sets, the computer shuts off the 12-volt supply to the transmission,
keeping the transmission in 3rd gear.
Repair the trouble codes first. If the high governor pressure is high without trouble
codes, you’ll need to perform further diagnosis: While watching governor pressure with a
gauge, use a scan tool to monitor “Desired Governor Pressure” and “Actual Governor
Pressure.” All three should read about the same. Unless the computer is bad or there’s a
bad input to the computer, the desired pressure should follow vehicle speed fairly
1) If the pressure transducer is good, but a bad governor pressure control solenoid is
causing the high governor pressure, the “Actual Governor Pressure” and the pressure
gauge reading should read the same, both of which will be higher than expected.
However, the “Desired Governor Pressure” won’t match the “Actual Governor Pressure”
or the pressure gauge reading.
2) If the pressure transducer is lying to the computer, the “Desired Governor Pressure”
and the “Actual Governor Pressure” may or may not be the same. However, the pressure
gauge reading will definitely not be the same as the “Desired Governor Pressure.”
3) If the governor pressure control solenoid and the pressure transducer are bad, the
only reading you can trust is from your pressure gauge. If the scan tool readings
make no sense, try changing both the transducer and the solenoid.

sj-x 500
12-25-2006, 12:13 PM
ok, now we're gettin somewhere, now... where is the pressure port, saw 2-3 pipe or o-ring boss plugs on the pass side of the tranny, any idea which one?

bc baja
12-25-2006, 02:52 PM
here are the ports.i think you will have better luck with data though.is the truck starting out in any other gear but 1st from a stop? there are only 4 electronic things in that trans ,1 sol for 4thgear, 1sol for lock up.1transducer,1 gov variable motor.the last two are the problem(quite common)there the round ones.

sj-x 500
12-25-2006, 03:44 PM
it always starts in 2nd, unless i mat it, or select 1st gear. od works, as does the lock up.

i will presure test it later today

sj-x 500
12-25-2006, 05:54 PM
k, just tested it, at 10 mph, it showed over 45psi.

almost certain it's a solenoid bypassing

bc baja
12-25-2006, 11:25 PM
so thats not right...right? ether the gov sol is fucked,or the transdcer is fucked & telling the computer to increace pressure.ether way repace them both !

sj-x 500
12-26-2006, 12:00 AM
yea, looks like it, too bad you have to buy both to be sure, it'd be nice to just swap out the faulty unit.