2001 transmission flow valve and solenoid

[donpiontek]

Hello All:

I've been reading several posts on the valve and solenoid problems with the 4T56E transmission for the 3.5 My 2001 has 150K on it, and the tranny had been good until recently when the "hard shift" from 1st to 2nd is happening with greater frequency (especially in hot weather).

The pressure valve and solenoid replacement will run $600 - $700, or so it seems. I've had the tranny flushed on a regular basis, the last time about two weeks ago. Everything checked out then. I just spoke to a recommended transmission shop who told me that I should go with a complete overhaul and converter re-build for around $2,800! Is this necessary? The posts seem to indicate that the valve-solenoid service should cure the problem. Any thoughts?

[centennialman]

Have you had the car scanned for codes and has it gone into max shift adapt?

Secondly, and sorry to be vague, but I was having the same problem and the stealership mentioned that there was a TSB (don't know the number) concerning this problem, and that an aid (not necessarily a cure) was to reroute a pressure line )don't know which one) away from a hot spot. They did the reroute and I only get the problem maybe twice a year. It always clears after a restart. If you determine that the problem is heat related, a tranny cooler is a far cheaper alternative. Get one that has a thermostat - there are a few posts around on this topic.

[aurora2001tan]

If anyone wants a gm tech flyer that came out oct 2000 that details the problems with these transmissions, the magnastear system and other things send me your email. If you want the gm tech bullitan on the PCS hard shift issue tell me to send that too. Just PM me


I am getting my PC solonoid done this fall or sooner for under 400 bucks i think, first quote was 500 bucks but after i talked to them again about how to test it and the procedure the price seemed to come down, I dont think they are scared of the car anymore LOL. Esp since I fixed all the other problems. They know I could do the job myself if I wanted to.

Transmission shop. I asked our local transmission shop the same question and offered to pay for a diagnostic, after talking to the guy for a bit he told me the same thing, install a new transmission.

I then went to the dealer to schedule a by the book diagnostic with the pressure gauge. They said
" not worth doing" " Transmission shop said what? you dont need a transmission. A new PCSolonoid takes care of 99 percent of them"

10 years ago you could have a transmission rebuilt for 400 bucks. Not anymore. I assume that has something to do with the "you need a rebuilt transmission".

[aurora2001tan]

4T65E Transmission Delayed Shifts, Slips, Flares or Extended Shifts During Cold Operation (Replace Shift Solenoid Valve Assembly) #01-07-30-014
4T65-E Transmission Delayed Shifts, Slips, Flares or Extended Shifts During Cold Operation (Replace Shift Solenoid Valve Assembly)
2001 Buick Century, LeSabre, Park Avenue, Regal

2001 Chevrolet Impala, Lumina, Monte Carlo, Venture

2001 Oldsmobile Aurora, Intrigue, Silhouette

2001 Pontiac Aztek, Bonneville, Grand Prix, Montana

with 4T65-E Automatic Transmission (RPOs MN3, MN7, M76, M15)

Condition
Some owners may comment on one or several delayed shifts, slips, flares or extended shifts during cold operation. These symptoms can affect the 1-2 shift only. The transmission won't shift out of 1st gear until the temperature is high enough to unstick the solenoid. This condition can last up to several shift patterns. These symptoms can return after the vehicle sits, usually 6 hours or more.

Cause
The 1-2, 3-4 shift solenoid valve not exhausting may be the cause of these conditions.

Correction
Replace the 1-2, 3-4 shift solenoid valve. Refer to the appropriate Service Manual information for replacement procedure.
==================================================================
I HAVE GOTTEN ONE OF THESE DIC CODES MAX ADAPT AND SINCE IT IS INTERMITANT I AM GOING WITH THE FOLLOWING INSTRUCTIONS.

Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly) #00-07-30-002B
Table 1: Line Pressure Specification Table
Slips, Harsh Upshift or Garage Shifts, Launch Shudders, Flares, Erratic Shifts and Intermittent Concerns, DTC P1811 or P0748 Set (Replace Pressure Control Solenoid Valve Assembly)
1997-1999 Buick Riviera

1997-2002 Buick Park Avenue

1998-2002 Buick LeSabre

1999-2002 Buick Regal

2000-2002 Buick Century

2002 Buick Rendezvous

1997-2001 Chevrolet Lumina

1997-2002 Chevrolet Monte Carlo

1999-2002 Chevrolet Venture

2000-2002 Chevrolet Impala

1997- 1999 Oldsmobile Eighty Eight

1997-2002 Oldsmobile Silhouette

1998-2002 Oldsmobile Intrigue

2001-2002 Oldsmobile Aurora (3.5L)

1997-2002 Pontiac Bonneville, Grand Prix

1999-2002 Pontiac Transport/Montana

2001-2002 Pontiac Aztek

with Hydra-Matic 4T65-E (RPOs MN3, MN7, M15, M76)

This bulletin is being revised to add additional models and model years. Please discard Corporate Bulletin Number 00-07-30-002A (Section --Automatic Transmission).

Condition
Some owners of the above vehicles with a Hydra-Matic 4T65-E transaxle may comment on harsh upshifts or harsh garage shifts, soft shifts, shudders on hard acceleration, or shifts erratic. These conditions may appear intermittently or set a DTC P1811 or P0748. During diagnosis, a low or high line pressure (actual versus desired) may be observed.

Cause
The above condition may be due to any one of the following which may affect line pressure output:

Sediment inside the pressure control (PC) solenoid valve, causing the PC solenoid valve to mechanically bind.
Sediment in the valve body, causing the torque signal regulator valve to stick.
Incorrect transaxle oil level.
Correction

Important
Any of the above conditions may be intermittent, therefore, this test should be performed at least three times.


Refer to the Line Pressure Check Procedure in SI, along with the Line Pressure Specification Table below, to determine if actual versus desired pressures are within the values specified. The Scan Tool is only able to control the PC solenoid valve in PARK and NEUTRAL with the vehicle stopped. This protects the clutches from extremely high or low pressures in DRIVE or REVERSE ranges.

Refer to the Line Pressure Specification Table below. The pressures in the table assume a temperature of 70°C. The pressure will vary with a change in temperature.

Line Pressure Specification Table Pressure Control Solenoid Valve Current
Approximate Line Pressure*

Metric
English

0 amp
1675-2137 kPa
243-310 psi

0.1 amp
1662-2124 kPa
241-308 psi

0.2 amp
1613-2103 kPa
234-305 psi

0.3 amp
1551-2068 kPa
225-300 psi

0.4 amp
1448-1986 kPa
210-288 psi

0.5 amp
1310-1903 kPa
190-276 psi

0.6 amp
1172-1751 kPa
170-254 psi

0.7 amp
1000-1531 kPa
145-222 psi

0.8 amp
793-1227 kPa
115-178 psi

0.9 amp
565-896 kPa
82-130 psi

1 amp
469-641 kPa
68-93 psi

1.1 amp
448-552 kPa
65-80 psi

*Approximate Line Pressure is measured at an engine speed of 1400 RPM.


If the actual versus desired pressures are not within the values specified, clean the valve body and replace the PC solenoid valve, if necessary.

Check the PC solenoid valve actual versus desired pressures to verify the new PC solenoid valve is responding correctly.

Refer to the Automatic Transaxle Section of the Service Manual for the proper repair procedure.

Line Pressure Check Procedure
Tools Required
J 21867 Universal Pressure Gauge Set


Important
Before performing a line pressure check, verify that the pressure control (PC) solenoid valve is receiving the correct electrical signal from the PCM.


Install a Scan Tool.

Caution
Keep the brakes applied at all times in order to prevent unexpected vehicle motion. Personal injury may result if the vehicle moves unexpectedly.


Start the engine and set the parking brake.
Check for a stored Diagnostic Trouble Code (DTC).
Repair the vehicle, if necessary.
Check the fluid level. Refer to the Transmission Fluid Checking Procedure.
Check the manual linkage for proper adjustment.



Turn the engine OFF. Remove the oil pressure test hole plug and install the J 21867.
Put the gear selector in PARK range and set the parking brake.
Start the engine and allow the engine to warm up at idle.

Notice
Total test running time should not be longer than two minutes, or else transmission damage could occur.


Access the PC solenoid valve control test on the Scan Tool.
Increase the PC solenoid actual current from 0.0 to 1.0 amps in 0.1 amp increments. Allow the pressure to stabilize for five seconds after each pressure change. Read the corresponding line pressure on the J 21867.
Refer to the Line Pressure specification table. Compare the data to the table.
If pressure readings differ greatly from the table, refer to Incorrect Line Pressure.
Remove the J 21867.
Apply sealant, P/N 12345382 (in Canada, P/N 10953489), to the oil pressure test hole plug.

Notice
Refer to Fastener Notice in Cautions and Notices.


Install the oil pressure test hole plug. Tighten
Tighten the oil pressure test hole plug to 12 N·m (106 lb in).

[mdub1666]

how long can you drive with this issue and not have a major problem or breakdown?

[littlet01]

I'm also curious if there are any long term issues with just driving with the hard 1-2 shift. It only appears in a WOT shift so its not that annoying.

[aurora2001tan]

Somebody said they had had this issue for along time and nothing has changed. Another person warned not to let it go for too long as it could cause damage.

Quick shifts used to be a hot rodders mod on a typical 350 auto trans. Personally since we are shutting it off, open door, close door. Resetting the fault...then the trans really isnt operating in fault that long. If its smooth than the pressure is correct. Right?

[droach2]

I've had the hard shifting probelm with my 2001 Aurora for some time now (about 2 years). It is very interrmittent, but it seems to happen more in the warm weather and not very often in the winter. Anyways, I had the pressure control valve changed because the transmission was making a high pitch squealling noise. I also had the pressure sensor assembly and some shift valves replaced for $750. This did NOT fix the problem. The hard shifting came back within one month. I found that the hard shiftings occur when I get codes P0716 & P0717. The PCM goes into some maximum pressure mode to make sure the valves shift. I clear the codes and the transmission begins to shift normally again.

Anyways the codes refer to the input speed sensor within the transmission. I also had that replaced during the pressure control valve replacement procedure. So it seems that the problem must be external, maybe in the wiring harness or PCM software. I will be checking the wiring this weekend to see if I can find something wrong.

[aurora2001tan]

The only trans code I have found was an OLd Max shift p 1811 and that was in November. The code has note returned. The transmission oil was good but a bit overrun. So maybe the new fluid took care of that old one time accurance. This code actually could have been caused by the faulty TPS sensor too as I was told by a gm service instructor.

There are alot of things going on in these transmissions and since I work on machines I know that codes can often show them selfs pointing to one area when actually something else caused another area to code. My pcm was replaced under warranty at 21000 miles.

My dealer swears the pc solonoid fixs 99% percent of the problems. I didnt ask about the other 1 % .

Shepards in kendallville IN One of their guys name in Kieth, Hes been there since forever... since he was a kid. He knows GM cars.

Back to a contact I have that is a GM instructor. He had this to say also.

" It is common for the PCS to fail due to sediment and debris in the valve, however there could be a sticking valve in the valve body, check the valve body good while changing the PCS.

If all shifts take longer than they should that could be a low line pressure problem. If only one shift takes too long clutchs or bands have a problem and it needs an overhaul.

PCS is diagnosed this way. INstall pressure gauge and command solonoid with the scan tool. The pressure should increase stedily as the current decreases with the engine running in park or neutral. If line pressure doesnt act in this way the solonoid may be at fault. Note: You can command the PCS current up or down with the scan tool while watching the pressure gauge. "
end of quote

Since I havent talked to the guy for almost a year I am going to be contacting him again about this transmission problem and a rumor that it really needs reprogramed and GM will not do it , something of that nature. Ill post back what he says about it.

[aurora2001tan]

Basically GM instructor refered to my previous ramblings about this subject. One interesting thing to note about this problem is that now that it is winter. This hard shift has NOT HAPPENED AGAIN. Cooler temps seem to be helping the solonoid I guess.
I almost want to do the job myself now since the car is totally running like a champ for awhile now. Owell its going to get done soon no matter what!!!

[buck91]

Is this something a DIY can handle? Any service manual procedures?