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1997 P30 Gm Stepvan not shifting out of 2nd gear

Messages
5
Likes
1
Location
Brooklyn New York
Thread starter #1
Hi,
I have a 1997 Chevy p30 stepvan. Hoping someone can help. Truck was driving fine till I brought it in a shop for an engine oil change and a brake adjustment. I pull out of the shop and truck wouldn’t come out of first gear. Park, reverse and drive is fine, no jerk at all. Fluid clean. Truck drives and revs not going out of first gear. Brought it in to a few trans shops and all are saying needs a rebuild trany without looking and checking it.. any help would be appreciated!
 

Jaryd

Love my 6.5
Messages
779
Likes
997
Location
Hodges, SC
#8
Limp mode is when the transmission won’t shift like yours is doing to protect itself from more damage and to help you make it home in a pinch.

I think there are a couple different reasons for the transmission to go into limp mode. Like said above, You need to get a scanner on it to have some sort of idea of which way to go.

If it was running fine when you brought it to the oil change station then I don’t see why you would need a rebuild all of a sudden.

I’m betting that they have done something to the transmission wiring harness while they were under there.

@THEFERMANATOR
 
Last edited:
Messages
5
Likes
1
Location
Brooklyn New York
Thread starter #11
Thanks,
So I went to a shop today and they believed the truck was in limp mode as you guys said. They also think it’s a glitch and unplugged the battery for 20 min to reset the computer. They tested some sensors and found no problem with wires or sensors. Truck now shifts out of gear and drives normal. I feel like this problem will come back. Any thoughts? Does this sound about right?
 

Jaryd

Love my 6.5
Messages
779
Likes
997
Location
Hodges, SC
#12
I’m just guessing here but, you might have a nick somewhere in the harness and it’s grounding out. They got up under there and moved stuff around and “ungrounded” the wires.

If it ever happens again. Shut it off. Climb under it and try moving the wiring harness around and then start it up and see if it fixed the problem.
 

WarWagon

Well it hits on 7 of 8...
Messages
8,350
Likes
2,851
Location
AZ
#13
Hi,
Thank you for replying. There is no check engine light coming on.
To be blunt so it makes sense: Service ENGINE Soon is NOT Service Transmission Soon! The "It's going to cost GM warranty money SES light" only comes on because the EPA is holding a gun to GM's head. The light is nearly for emissions failures only.

@MrMarty51 is correct in suggesting getting a code reader on it. 'Disconnected the batteries' should not clear the code from memory. Older stuff it can clear codes completely and I am fuzzy if it would for your year. (Battery disconnect can reset the limp mode, but, this is generally done by normal key off key on. @Jaryd eludes to key off key on reset. The ECM checks for the condition after key on and only limps again if the condition still exists. ) The correct way to reset a limp mode is with a scanner - the battery disconnect is an outdated hack to get you down the road hoping it's intermittent without fixing it. Stop by an auto parts store and have them scan for codes. Did the shop tell you what codes were in the computer? Again this code is just for future reference if the problem comes back. The shop may have fixed the problem, like pinched wires, w/o telling you.

Again it limped so it will have a code as to why it limped.

What's the trans oil look like? Level?

What items do you move to change the oil? Look around the oil filter for damaged wires. Doghouse pinching wires?
 

Will L.

Well-Known Member
Messages
7,838
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6,871
Location
Boulder City Nv
#14
Something I did once was trans filter change and pinched the wire inside the trans with the pan. That one took a bit to realize. Everytime I started the truck it would drive theough all 4 gears. Then when slowing down it would default to 2nd gear only. It reset every time the key was cycled. Annoying. I had 3 different trans shops tell me “full rebuild”.

I only found it because he brand filter I used, I heard had some tearing problems. (Wasn’t my issue) So when I threw in a different filter, I saw the wire. Figuring a rebuild was needed, I just left the flattened wire but not pinched this time. Over 30k miles later, all is good.
 
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