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2004 Silverado hard shift from 1st to 2nd...solutions?

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88K views 16 replies 9 participants last post by  davester3500  
D
#1 ·
Hi all,

I am new to this forum and new to Silverados. I just purchased a 2004 z71, and I really like it. I does have one minor issue that bugs me though. Sometimes it tends to shift a little bit more harsh than I would like it to when it upshift from 1st to 2nd gear.

I have looked all over this forum and all over the rest of the internet and from what I can tell this is a pretty common issue with the silverado transmissions. The funny thing about it is that it does not happen when the truck is not warmed up yet, it ONLY happens when the truck is at normal operating temp. From hours of searching, most people say that it is some sort of pressure issue.

Out of the possible solutions that I have come across, most people say it is a trans programming issue (like the ECM needs to be "re-flashed") or some sort of valve/pressure issue with the trans. Some people fix it with trans reprogramming kits, and one guy even said that getting his fluid changed helped.

My bottom line is that I have searched all over, and I have yet to find one consistent answer to this problem that seems to be quite common. Does anyone have any experience with this issue? I will add that this shift is not terribly hard, just a little bit harder than I would like it to be. It's almost like it delays a second, then suddenly shifts up to second and ever so slightly pushes you back in your seat. Like I said, it's not that bad, but I definitely notice it, and I would like it gone. I should also add that my fluid is a nice red and does not smell burnt, and upon taking my truck to autozone so they could pull the codes, it is not throwing out one single code.

I appreciate any insight in advance.
Dave
 
D
#6 ·
SilverSurfer said:
The latest tsb says to install new 1-2 accumulator valve kit. It says nothing (this time) about reflashing the TCM.
Mine shifts harder when cold and smooths out after it warms up.
Click to expand...
Which TSB is that? Here is one I found from another forum:
Transmission 1-2 Shift Shudder, Vibration, Slips, Chuggle (Install Generator Voltage Sense Circuit) #02-07-30-030 - (08/09/2002)

Transmission 1-2 Shift Shudder, Vibration, Slips, Chuggle (Install Generator Voltage Sense Circuit)

2001-2003 Chevrolet Silverado

2001-2003 GMC Sierra

with 4L60-E Automatic Transmission (RPO M30)

Condition
Some customers may comment that the transmission slips, a shudder, chuggle, or vibration is felt when the transmission shifts from first to second gear.

Cause
A 12 Hz electrical feedback from the charging circuit may be affecting the transmission pressure control solenoid, causing a fluctuation of the line pressure within the transmission.

Diagnostic Tip
Road test the vehicle under the following conditions:

Throttle position is less than 15 percent.
Engine coolant and transmission fluid are at full operating temperature.
The outside ambient temperature is warmer than 24°C (75°F).
If the condition is present, disconnect the generator 4 cavity connector (2 wires in the connector) and retest.

If the condition is no longer present, perform the correction listed below.

If the condition remains unchanged, the condition will not be corrected with this procedure. Look for other causes of the condition.

Correction
Install an external sense lead to the generator assembly. This is accomplished by adding a wire from the generator four wire connector to the generator output BAT terminal.

Disconnect the negative battery cable from the battery/batteries.
Slide the protective boot on the generator BAT terminal aside and remove the retainer and wire cable from the BAT terminal.
Unplug the generator 4-cavity terminal from the top of the generator.
Remove and save the orange weatherpack seal and CPA from the 4-way connector.
Using the proper terminal removal tool, remove the two wires from the 4-way connector.
Install a red cavity plug, P/N 12059168, into cavity "A" of the new 4-way connector, P/N 12186568.
Install the brown (Circuit 25) wire of the vehicle wiring harness into cavity "B" of the new 4-way connector.
Install the gray (Circuit 23) wire of the vehicle wiring harness into cavity "C" of the new 4-way connector.
Obtain a piece of 0.80 mm/18GA black wire, 254 mm (8 in) long.
Install a red terminal seal, P/N 12048086, and terminal, P/N 12048074, (crimp and solder) on one end of the new black wire.
Install the new black wire into cavity "D" of the new 4-way connector.
Reinstall the connector seal and CPA, from the original connector, to the new connector.
Plug the 4-way connector into the generator.
Route the black wire to the generator BAT terminal, sliding the wire into the small end to the output terminal boot, along side the generator output wire.
Crimp and solder the ring terminal, P/N 02977821, on the open end of the new black wire.
Place the generator output wire and the new black wire onto the generator BAT terminal and install the retainer. Tighten
Tighten to the BAT terminal retainer to 9 N·m (80 lb in).

Connect the negative battery cable. Tighten
Tighten the battery cable retainer to 17 N·m (13 lb ft).
 
D
#7 ·
SilverSurfer said:
GM Parts Direct lists the conversion kit at $20, sale $12. Labor guide shows 1.4 hrs. So I'd guess $200 out the door if you went to the dealer. Disclaimer: THIS IS ONLY A GUESS, DON'T QUOTE ME ON THAT PRICE.
Click to expand...
Which conversion kit is it? Is this stated in the latest TSB? These service reps at the dealership just want to rebuild my trans unless I provide them with a specific TSB, they are worthless.
 
#8 ·
I left out the pics, there a PITA to transfer over. I've seen all the bulletins on this. This one's the cheapest fix I've seen so far.

TECHNICAL

Bulletin No.: 09-07-30-017B

Date: April 29, 2011

Subject: 1-2 Shift Flare with an End Bump or Harsh 1-2 Shift at Light Throttle (Install New 1-2 Accumulator Valve Kit)
Models:
2003-2007 Cadillac Escalade
2003-2007 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2003-2007 GMC Sierra, Yukon, Yukon XL
All Equipped with 4.8L or 5.3L Engine (RPOs LR4, LM7, L59, LM4, LH6, L33)
and 4L60E Automatic Transmission (RPO M30)
Please Refer to GWM/IVH
Supercede:
This bulletin is being revised to add a condition to the Subject and Condition Information. Please discard Corporate Bulletin Number 09-07-30-017A (Section 07 - Transmission/Transaxle).

Condition

Some customers may comment about a 1-2 shift flare with an end bump or a harsh 1-2 shift at light throttle.

Cause

This condition may be caused by the 2-4 band apply time extending through the 1-2 accumulator stroke.

Correction

1. Verify the customer's concern.
2. Remove the valve body. Refer to Valve Body and Pressure Switch Removal in SI.
3. Remove the coiled spring pin (360).
4. Remove the 1-2 accumulator valve sleeve (372).
5. Remove the 1-2 accumulator valve (371) and the 1-2 accumulator valve spring (370).
6. Install the new 1-2 accumulator valve kit, GM P/N 24255821.
7. Install the valve body. Refer to Valve Body and Pressure Switch Installation in SI.

Parts Information

Warranty Information

For vehicles repaired under warranty, use the table.
 
H
#9 ·
I'm sure someone has already mentioned/suggested this to you.. but, I would HIGHLY recommend a corvette servo kit for your transmission. It's easy to install and will greatly change your 1st to 2nd and 2nd to 3rd gear-changes for the better.

Basically, your transmission will shift like a corvette shifts. Nice and firm.. and the servo will have a better gear-holding capacity.. meaning less down and upshifting.. meaning a happier transmission.

Seriously, its something you should REALLY look into doing.

Best of luck.
 
S
#11 ·
Glad I found this thread. I took my 2005 1500 Z71 to the Chevrolet dealer and they quoted me $700 with fluids to replace valve body cover... or something to that effect. Advised I try TransX or Lucas equivalent first. I did that but it has not helped. I was about to take it back and spend the $700. Maybe this will save me a few bucks. :fingers-crossed:
 
S
#13 ·
Well... maybe I am NOT glad I found this thread, as it has cost me an extra $358, although I can deduct $56 for the filter kit, which I would have done if I had the valve body replaced. Now I will end up with about $1,000 in it eventually. The accumulator kit (they labeled it conversion kit $19.74) did not fix the hard shift from 1st to 2nd. I think it may be slightly better, but I need to drive it more. They did tell me that they found fine metal on the magnet that they cleaned off... could not tell where it was coming from.
 
G
#14 ·
Hi first time poster
I have a 2007 1500 classic with the vin b 5.3l and it randomly shifts hard 1-2 .
I have rebuilt the Trans and fix all the pressure and clearance issues they have put in a top quality tqconv and had the throttle body and acc pedal replaced with new parts not reman.
I swaped out the maf with a known good one whats left I'm at my wits end here any help would be greatful
Thanks
James
OH its seems to want 53% engine load at 20% throttle any one else think thats high? had it flashed too no help
 
B
#15 ·
I had this same problem with my 2006 l60e. it was not shifting smoothly from 1st to 2nd. It would rev higher than normal then shift. I took it to a transmission specialist and he new exactly what it was. A common problem with these transmissions. It was explained to me that the valve body wares out. there are check valves for the pressure regulation. These check valves ware. there are a steel check balls that seat in the aluminum valve body. The aluminum wares. There is a kit that puts new steel seats in the valve body. After that it shifted like new, never had another problem until I cracked the truck up. This is such a common problem with these transmissions that he new exactly what it was just by my description and had the rebuild kits in stock because he does so many of them. Cost about $400 for the work and kit. Replacing the valve body is expensive, I think the kit with steel seats will be better than a new valve body with aluminum seats that will ware out again. The seats on the valve body had worn to the point that the check ball was almost through the port. Steel check balls in aluminum seats, what the hell does Chevy think will happen? The kit taps in new steel seats.
 
D
#17 ·
What? That doesn't sound even remotely correct. Vacuum in the intake manifold won't be significantly affected by sucking up some oil from the crankcase instead of just vapors.
 
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