Allison 1000 Issue

[kurt1993]

I have a 2001 Gmc Sierra 2500HD 4x4 w/ the 8.1L and Allison tranny it just rolled 50K miles and as i was plowing today i shifted as usual from forward to reverse when i was at a complete stop i herd a loud clunk (considering the transmission is silent when it usually shifts) and the truck jerked as it locked into reverse where it would usually just lock smoothly into reverse i finished up the plowing job taking it real easy but the truck would still clunk and jerk forward when shifted into drive and backward when shifted into reverse. I also noticed on the dash the little gear indicator would blink and not lock into a solid state unless it was in Park or 3 and my Service Engine Soon Light came on too.

 

I would like to know if i have any serious transmission issue or if its something more simple like a solenoid? do i need a complete rebuild or just something simple?

 

Thanks i would really appreciate any sort of helpful advise or answer

 

-Kurt

[8.1HD/ALLISON]

Sounds like its time to head to the dealer for a diagnosis of that light and see whats going on.

[gmtech4]

you have a code in the transmission control module (tcm),you have to get it diagnosed or get the code retreived and repost what the code is..

 

TTY soon

 

 

the transmission programming commands max line pressure with the code activated to save itself and get your attn,worked out great....those are awesome transmissions

 

see your owners manual for more info

 

haaa,ya beat me to it matt !!! lol

[kurt1993]

you have a code in the transmission control module (tcm),you have to get it diagnosed or get the code retreived and repost what the code is..

 

TTY soon

 

 

the transmission programming commands max line pressure with the code activated to save itself and get your attn,worked out great....those are awesome transmissions

 

see your owners manual for more info

 

haaa,ya beat me to it matt !!! lol

 

thanks im really hoping its nothing too serious any ideaS on what it could be?

[gmtech4]

no

[kurt1993]

no

 

Sorry if i upset you by posting more than once but i do really appreciate your help with my problem there were three codes but one of the codes appeared twice

 

they were

 

P0700

 

P1713

 

P0700

 

i had the guy clear the codes and the problem went away but i really dont want the problem re surfacing and there could also be some damage due to the clunking into gear and the intense jerks so if you could please tell me what my issue was and if i can do anything to prevent it from happening in the future i would really appreciate it

 

thanks so much,

 

-Kurt

[ChevyTech77]

P0700 is set because the TCM asked the ECM to turn the service engine soon light on.

 

P1713 is the same as a P0875 for 02-04 model year vehicles (all diagnositic information and most of the dtcs changed between the 01 and 02 model year Allison transmissions).

 

Tough to say what exactly is wrong with it without having the truck and performing the diagnosis while the concern is present. If it is intermittent, it could have just been water entry into the PRNDL switch or coule be a PSM card in the transmission going out. I don't see any reason to think that it is an internal trans issue. I'd be guessing on a PRNDL switch though for as many as we have seen fail.

[gmtech4]

im not upset at all Kurt..

 

i got this from google and justanswer,

 

this is not a full diag trouble tree ,it gives good info on what happens /when and why,and diagnostic aids

 

 

Circuit Description

 

The pressure switch manifold (PSM) is a multiple switch assembly made up of three normally open (N/O) pressure switches and one normally closed (N/C) pressure switch for reverse pressure. Fluid pressure is supplied to the reverse pressure switch when the manual selector valve is in any position except REVERSE. When the manual selector valve is moved to REVERSE, pressure to the reverse pressure switch is cut off, causing the switch to close.

 

DTC P1713 is a type A DTC.

 

Conditions for Running the DTC

The components are powered and ignition voltage is greater than 9.0 volts and less than 18 volts.

Engine speed is greater than 200 RPM and less than 7,500 RPM for 5 seconds.

The park/neutral position switch (PNP) is enabled and functional.

The transmission fluid temperature (TFT) is greater than 0°C (32°F).

DTC P0708 and P1714 are not active.

Conditions for Setting the DTC

 

DTC P1713 sets when PARK, NEUTRAL, or a forward range has been selected and the reverse pressure switch remains in the mechanically closed/electrically on position for a period of time that is calibration dependent.

 

Action Taken When the DTC Sets

The transmission control module (TCM) will illuminate the malfunction indicator lamp (MIL).

The transmission will lock in NEUTRAL.

DTC P1713 will be stored in TCM history.

The TCM freezes shift adapts.

The TCM inhibits torque converter clutch (TCC) engagement.

Conditions for Clearing the DTC

 

A scan tool can clear the code from TCM history. The TCM automatically clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without failure.

 

Diagnostic Aids

Inspect the wiring for poor electrical connections at the TCM. Look for the following conditions:

A bent terminal

A backed-out terminal

A damaged terminal

Poor terminal tension

A chafed wire

A broken wire inside the insulation

When diagnosing for an intermittent short or open, massage the wiring harness while watching the test equipment for a change.

You may have to drive the vehicle in order to experience a condition.

This DTC could indicate a hydraulic leak path exhausting pressure from the reverse pressure switch.

An inactive DTC P1713 set in combination with DTC P1711 often indicates an internal PNP switch failure occurred on a previous drive cycle. If this combination returns after clearing the DTCs, replacement of the PNP switch may be necessary.

The intent of this code is to detect discrepancies between the range selected at the PNP switch and the actual position of the manual selector valve.

Test Description

 

The numbers below refer to the step numbers on the diagnostic table.

This step tests the TCM response function.

This step tests the transmission wiring harness integrity.

This step tests and evaluates the internal wiring harness.

This step tests the PSM for a failed condition.

 

 

Read more: Chevy Questions - What does code P1713 mean I have a 2001 Chevy Silverado 2500 - JustAnswer http://www.justanswer.com/chevy/2x2fk-does...l#ixzz1BishORJJ

[gmtech4]

like chevytech (who does not have name lol) says the PRNDL switchws are crap but i have never diag'd a psm on an allison,...

 

i dont recommend throwing parts at it at all..

 

up to you though

[kurt1993]

http://www.gm-trucks.com/forums/index.php?...p;#entry1123385

 

most likely the best answer to my question....

[gmtech4]

yes the prdnl switch.why 3 threads kurt?

[kurt1993]

yes the prdnl switch.why 3 threads kurt?

 

why did i post the link on 3 threads or why did i make 3 threads in the first place? whats the question? lol

[gmtech4]

replace your prndl switch kurt and do not ask a question in 3 different topics areas again

[kurt1993]

replace your prndl switch kurt and do not ask a question in 3 different topics areas again

 

but um... the problem hasn't reoccurred so i mean im guessing its good for now and if it acts up again i sure will replace the prndl switch

[gmtech4]

change it anyways ,they are junk ,the new ones are better