95 K2500 4L80E problem

My transmission one day would not shift. It acts like it's in 2nd gear. The next day it shifted fine. The day after, it didn't shift again. I shut it off and started it right back up and it worked fine. It set code 81..1-2 shift solenoid, on the scanner. Has anyone had this trouble? What's the cure?

Pat
pjr1957@yahoo.com

The 1-2 shift solenoid can be replaced by dropping the tranny pan. There are 4 solenoids, 1-2, 2-3, 3-4 and TCC lockup.

I don't have a manual handy but I could look up which one is the 1-2 shift if you decide to do this yourself.

//2000CAYukon

So you think that changing the 1-2 shift solenoid would solve my problem? I am planning to do this myself so any info would be apreciated.

Is it code 81 or 82? 81 seems to be 2-3 shift solenoid not 1-2. See http://www.troublecodes.net/GM/

The solenoid or the wiring to it is probably bad. The solenoids themselfs are the same (i.e. 1-2 solenoid and 2-3 solenoid is the same part number).

A Factory Service Manual or a Hayes manual would be a good idea.

Of course, this would be a good time to change the filter while you are in there.

//2000CAYukon

Yes, It was code 81. Where is the solenoid located?

When you drop the pan, the 1-2 and 2-3 shift solenoids are at the rear. There are only 2 solenoids at the rear. The drivers side is 1-2 and the passenger side is 2-3.

I have a 96 FSM and it looks like they are held in by a screw (on the 4L60-E, they are held in by a clip). Just disconnect the electrical, remove the screw and replace.

//2000CAYukon

I took the pan off and the NAPA solenoid (#1-5404) I bought doesn't look quite like the original. It has a 2" (about) wire lead which the other just has a place to plug the connection on. I hate when the replacement parts are not exactly like the original. Is a GM solenoid the same or is it different too? What do you use?

I took the pan off and the NAPA solenoid (#1-5404) I bought doesn't look quite like the original. It has a 2" (about) wire lead which the other just has a place to plug the connection on. I hate when the replacement parts are not exactly like the original. Is a GM solenoid the same or is it different too? What do you use?

My experience is that the ac delco or dealer part is usually the same as what is being replaced. The exception is when something has been redesigned.

The Napa part probably fits many applications and they do not provide the terminal.

I have used Sonnax transmission parts but was unable to find a part number on their website for the 2-3 shift solenoid for the 4L80-E.

//2000CAYukon

I called GM and they told me the 1-2 solenoid was # 10478147 and the 2-3 solenoid was 10478148. Napa has the same # for 1-2,3-4 solenoid, 1-5404.

I called GM and they told me the 1-2 solenoid was # 10478147 and the 2-3 solenoid was 10478148. Napa has the same # for 1-2,3-4 solenoid, 1-5404.

Most likely the difference between 10478147 and 10478148 is the electrical connection. Since the Napa part does not have the terminal, it can be used for both.

//2000CAYukon

On my 95 overdrive and first are out would the new solenids fix this?

azlincoln,
Have you scanned for codes? Do you have a 4l60-E or 4l80-E?

This looks more like your problem: http://www.transmissionspecialty.com/parts/parts/77754-09K.htm

It has the 4l80-E with 206000 miles on it first gear will work first thing in the morning when its cold Its been doing this for quite a while and if i remember right it was showing code 81 or 82
thanks

I changed the solenoid and it's still doing the same thing. Code 81 is on it again.

I changed the solenoid and it's still doing the same thing. Code 81 is on it again.

Sorry to hear that. Sounds like something is wrong with the 2-3 shift valve (bad spring, seal or valve body is worn). Or there is an electrical connection problem to the solenoid.

There are valve body repair kits or the valve body can be replaced. I know that the 4L60E has some well known issues with the valve body wearing (the famous P1870 code). I don't know enough about the 4L80E.

Since the valve body needs to come out, now would be a good time to get the 4L80E-HD2 reprogramming kit installed (from Transgo). This kit probably includes new springs for the 2-3 shift valve along with other improvements over the stock tranny. It will also make your tranny last longer (by increasing pressure to the 3-4 clutch pack).

//2000CAYukon

Took it to a tranny shop and they said the ignition switch is not getting enough voltage to the trans. I guess I'm going to put in a new switch. I heard they were a pain to change.

Took it to a tranny shop and they said the ignition switch is not getting enough voltage to the trans. I guess I'm going to put in a new switch. I heard they were a pain to change.

Sounds better than a new valve body or transmission rebuild.

Did you have a remote starter switch installed recently? I have heard that they can cause low voltage to the transmission if they are not installed correctly.

//2000CAYukon

Took it to the local tranny shop and they said the ignition switch is bad. How much of a job is it to change that?

No remote starter on here.

It was the ignition switch.

It was the ignition switch.

How bad was it to replace.

//2000CAYukon

It was a bad ignition switch.

I've have the flu so I won't do it till next week sometime. Sounds like it's not too bad of a job.

You may also want to check the wiring from the ecm to the solenoids and make sure that its not broken...seen alot of people replace parts when the actual problem is in the wiring harness.

Put the new switch on and it shifts fine now. It was pretty easy to change out but you need and E4 torx socket, preferably a deep one to unbolt it from the column.