Anyone have the TSB for the Transmission PCM ground update?

[BlazerLT]

I was told that there is a TSB for a ground update for the transmission pcm connection ground.

I just had my transmission rebuilt and I have a soft 1-2 shift sometimes that was there before the work.

They say the PCM ground for the transmission portion has to be improved and it solves the shift problems.

Anyone have it?

[herkyhawki]

I don't have the TSB right here, but here's link to your own previous post on this. See the answer I posted there.

http://www.automotiveforums.com/vbul...light=12167310

also see this link http://www.fullsizechevy.com/forums/...p/t-40010.html

If you do a google search on "12167310" you will find lots of forums that have more info.

[MT-2500]

Give us the year and i will check TSB,s on it.
I have found some for a harsh but no soft 1-2.
Any code setting?
Here is a link to a good trans forum if you want to ask Transman about it.
Feel free to run a post on it.
He is one of the best trans tech I know.
http://www.batauto.com/cgi-bin/Forum...rum_name=trans

MT

[BlazerLT]

It essemtially is the 1996 VCM ground update that was mentioned earlier.

Anyone got the instruction set? I think this can be done with buying any parts from GM.

[blazee]

There's a summerized version in one of the links that herkyhawki posted.

1. Remove the negative terminal from the battery.
2. Move the wire located at connector J3 (WHITE/GREY/CLEAR), pin 18 to connector J1 (BLUE), pin 23.
3. Install the jumper wire between connector J2 (RED), pin 26 and connector J3 (WHITE/GREY/CLEAR), pin 18.
4. Install the tag included in the kit around the VCM wiring harness. This tag notes that the wiring harness has been modified.
5. Reconnect the negative battery terminal.

[blazee]

I'll go ahead and repost the whole TSB here so people can find it while searching our forums:

00-07-30-026 - (12/21/2000) Automatic Transmission 1-2 and/or 2-3 Upshift Slip/Flare, No 3rd or 4th gear, Launch Shudder (Revise VCM Wiring)
1996 Chevrolet and GMC C/K, S/T, M/L, G1, G2, P3 Models
1996 Oldsmobile Bravada
with VCM and 4L60-E (M30) or 4L80-E (MT1) Automatic Transmission

This bulletin is being reissued to ensure that correct procedures are followed for this condition. Please discard Corporate Bulletin Number 66-71-03A (Section 7 -- Automatic Transmission).

Condition
Some owners may comment that the automatic transmission has either a slip or flare on the 1-2 and/or 2-3 upshift, or no 3rd or 4th gear, or launch shudder. Upon investigation, the technician may find a DTC P1870 stored in the VCM.

Cause
A poor internal ground between the two circuit boards of the VCM may cause the VCM to command erratic line pressure at the pressure control (PC) solenoid valve.

Correction
Using harness jumper wire and instruction kit, P/N 12167310, revise the wiring harness at the VCM connector. Corrections were made to the VCM beginning 2/14/96. The corrected VCMs are identified with service number 16244210 on the VCM identification label.

Procedure
The following is a summary of the instructions included with the service kit:
1. Remove the negative terminal from the battery.
2. Move the wire located at connector J3 (WHITE/GREY/CLEAR), pin 18 to connector J1 (BLUE), pin 23.
3. Install the jumper wire between connector J2 (RED), pin 26 and connector J3 (WHITE/GREY/CLEAR), pin 18.
4. Install the tag included in the kit around the VCM wiring harness. This tag notes that the wiring harness has been modified.
5. Reconnect the negative battery terminal.

Road test to verify that the condition has been corrected. If any of the following conditions are noted, the transmission should be repaired or replaced using the most cost effective method. Canadian dealers should repair the transmission.
1. Transmission fluid oxidation or excessive sediment.
2. Transmission slip or flare after this service fix is performed.
3. DTC P1870 is stored on a 4L60-E (M30).

The following tools are available from Kent-Moore (1-800-345-2233) for use in removing and relocating the VCM wires:
1. J 41758 Terminal Tool; used to remove the wire from the VCM connector.
2. J 41759 Punch; used to punch a new hole through the connector seal.

Parts Information
Part Number: 12167310
Description: Harness Jumper Wire Kit
Qty: 1

[BlazerLT]

I was wondering if anyone has actually done this and whether or not they have some photos or a scan of the instruction sheet which sometimes has some illustrations.

With this information I might be able to fix this myself.

[MT-2500]

BlazerLT
I can post the VCM wiring and pin out if that would help.
MT

[blazes9395]

I have done this update when I rebuilt my tranny as a precautionary measure. I picked up the repair kit at my local dealership. It was complete with all the necessary stuff , including the instructions. Cost me around $50 canadian. It took me about twenty minutes to install.

[BlazerLT]

Sweet, and did it fix it?

[blazes9395]

As I said, it was done only as a precautionary measure. I never had a problem with it, I just did it to rule out that issue, had anything developed. I was there, it was apart, and so I did it.

[blazes9395]

Originally Posted by BlazerLT

I just had my transmission rebuilt and I have a soft 1-2 shift sometimes that was there before the work.

Anyone have it?

Do you know if they did a complete overhaul, with all the updates, or was it just soft parts, clutches/band? Big difference. Also do you know what was worn out in the tranny, this will always tell you where to look to find the problem.

[BlazerLT]

Yea, they showed me the parts.

The clutches were shot and you could see where the coolant was eating the clutch material away.

That and the plastic solenoid housings were soft from the dexcool leaching them.

But to save this thread from going off-topic, the soft 1-2 shift had nothing to do with the coolant seeing it was there before and after.

[BlazerLT]

Well, I bought the kit which is a foot long wire with pin connectors on it for CDN$58. What a friggin ripoff!!!!!

Looks at the instructions and they were beyond my capabilities seeing they needed a special tool to remove the wires from the PCM harness.

Went back into the dealer and they charged me an hour to install it which in my mind is ok seeing a screwup could have been much more costly.

No weird 1-2 shifts yet though, shifting is nice and tight.

[BlazerLT]

THIS IS AMAZING!

Over 1000 miles into the change over and ground update and the truck is performing flawlessly.

This also has stopped the random pinging which must have been caused by the bad internal ground and the transmission not being able to retard the timig during the shift properly.

I am so happy.