shift solenoid replacement

[cyrez00]

Hey guys,

As mentioned before in another post my shift from 2-3 is sometimes a bit harsh.

So after digging trough the board it seems that i need to replace my shift solenoids. (Whatever they are and whatever they do...)

Planning on doing that and will need to start ordering stuff (gaskets/ solenoids etc. etc.) unless you guys say it's no use and will not cure my problem.

Now there is also a mention in the FSM of a Pressure solenoid, having no clue what it does (regulating some kind of pressure? ), should i replace this one as well whilst i have everything apart?

Also, anything else which i can replace whilst i'm there?

Thanks for your input.

Marc.

p.s. already found a thread describing the whole procedure, so don't worry about that! seems i need to keep my balls in check (now i sound like my wife )

[wiz6728]

Hey guys,

As mentioned before in another post my shift from 2-3 is sometimes a bit harsh.

So after digging trough the board it seems that i need to replace my shift solenoids. (Whatever they are and whatever they do...)

Planning on doing that and will need to start ordering stuff (gaskets/ solenoids etc. etc.) unless you guys say it's no use and will not cure my problem.

Now there is also a mention in the FSM of a Pressure solenoid, having no clue what it does (regulating some kind of pressure? ), should i replace this one as well whilst i have everything apart?

Also, anything else which i can replace whilst i'm there?

Thanks for your input.

Marc.

p.s. already found a thread describing the whole procedure, so don't worry about that! seems i need to keep my balls in check (now i sound like my wife )

if yoU change them make sure yoU install the filter retaining bracket they give you BEFORE you reinstall the valvebody. i didnt had 2 do it 2x

[BodybyFisher]

Marc are you getting any tranny codes?

Correct me if I am wrong guys, but the symptom of a bad shift solenoid is NO SHIFTING, I don't think I recall HARD shifting solved by replacing the shift solenoids.

I do know this, when my ISS speed sensor went bad, one of the defaults, is for it to go into a default line pressure, and THAT caused hard shifts for me. Before I went to the trouble of changing the shift solenoids, I would put a gage on the LINE PRESSURE, to make sure your LINE pressure is not higher than normal. That could be the fault of the pressure solenoid in the side pan (that I also replaced for PM).

What kind of fluid are you using?, the new DEXRON VI?

[Ranger]

Yup, I think BBF is right on.

[cyrez00]

Marc are you getting any tranny codes?

Correct me if I am wrong guys, but the symptom of a bad shift solenoid is NO SHIFTING, I don't think I recall HARD shifting solved by replacing the shift solenoids.

I do know this, when my ISS speed sensor went bad, one of the defaults, is for it to go into a default line pressure, and THAT caused hard shifts for me. Before I went to the trouble of changing the shift solenoids, I would put a gage on the LINE PRESSURE, to make sure your LINE pressure is not higher than normal. That could be the fault of the pressure solenoid in the side pan (that I also replaced for PM).

What kind of fluid are you using?, the new DEXRON VI?

Mike,

No codes at all and the shift from 1-2 is smooth and 2-3 is only harsh when i push the car a bit, when with a relaced drivers style it is a smooth shift as well when WOTting is feels normal as well.

So... only under medium to high throttle it 'bumps' into the next gear.

I didn't use the newest Dexron, i think i used Dexron IV or V (need to check the container, its in the car and it's raining like h*ll here at the moment)

But i replaced the fluid only a month or so ago in the hopes to get rid of the hard shift..

gages on line pressure... there you lost me... which line and what should it be at?

[BodybyFisher]

Its either Dexron III or VI if I am not mistaken, unless you have different formulas near you, so check it if you would.

Try disconnecting the battery, I think that should reset the transmission adapts. Can someone verify that disconnecting the battery resets the tranny adapts or does it need to be done with a Tech 2?

If you have a manual, you will find a port on the leading edge of the tranny that you can connect a gage to, to see what your line pressure is. It is sounding to me like your line pressure might be higher than normal. That could be due to the transmission adapts. The tranny adjusts itself to your driving habits, since you have no codes, its possible that is the cause (just a guess) and resetting them could solve your problem.

If you have dog bones check them and look at your engine and tranny mounts, maybe its not tranny related?

Did this happen before the fluid change or is this the reason you changed the fluid?

[rmac-etc]

I have had very hard shifting from 1st to 2nd intermittantly for years. It was pretty frequent several years ago but rarely happens now. I have had the Input Speed Senser code ocassionally and that is probably the source, but I am not going in there ... ( there is a legend of one who did that very thing on this board and came back to tell the tale )

As to the shift solenoids, mine went bad, a while back and the symptom was that the transmission dropped down to 2nd gear and stayed there. Thats the 'limp home' feature. Your shift solenoids are not likely the source of the hard shifting, imo.

[cyrez00]

Hi guys,

Am using Dexron III, now i recall that i've seen somewhere that the higher specs were not advisable with my old tranny for whatever reason so i decided to stick with III.

Dog bones were replaced about 6 month's ago, those should be ok.

Will try the reset thing by removing the battery one of those days to see if that resolves anything.

Other ideas are more then welcome!

Thanks

Marc.

[BodybyFisher]

I found this, its under the term HARSH SHIFTS but maybe it will help

Harsh Shifts

Checks

Causes

DEFINITION: High Line Pressure

Actuator Feed Limit Valve

Stuck open

Calibrations

Not updated or incorrect platform

Checkballs

Missing

Final Drive Internal Gear Snap Ring

Missing

PCS Feed Valve

Stuck

Pressure Control Solenoid (PCS)

Failed OFF, intermittent short

Loose connector

Pressure Reg. Boost Valve

Stuck open

Pressure Reg. Valve

Stuck at high torque signal due to undersized bore, sediment or Pressure Control Solenoid failure

TFP Val. Position Sw.

Loose connector

Transmission Wiring Harness

Loose connection at vehicle harness

[cyrez00]

hmmm.... so much for an easy fix.....

So the first line of action is checking the pressure on the tranny and then take it from there?

[BodybyFisher]

hmmm.... so much for an easy fix.....

So the first line of action is checking the pressure on the tranny and then take it from there?

I would try resetting the adapts and if possible check the line pressure, I hope the below info is readable. This might be a job for a Caddy dealer to do with your instructions

Line Pressure Check Procedure

Line pressures are calibrated for two sets of gear ranges-Drive-Park-Neutral, and Reverse. This allows the transmission line pressure to be appropriate for different pressure needs in different gear ranges:

Gear Range

Line Pressure Range

Drive, Park or Neutral

Minimum line 50-55 psi, Maximum line 230-250 psi

Reverse

Minimum line 90 psi, Maximum line 300 psi

Before performing a line pressure check, verify that the pressure control solenoid for the transmission is receiving the correct electrical signal from the vehicle computer:

Hook up the scan tool.

Start the engine and set the parking brake.

Caution

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

Check for a P0748 malfunction code from the pressure control solenoid of the stored transmission. Check for other malfunction codes.

Repair the vehicle if necessary. Include the following areas:

Inspect the fluid level

Inspect the manual linkage at the transmission

Install the line pressure gage.

Put the gear selector in Park and set the parking brake.

Start the engine and allow the engine to warm up at idle.

Enter the diagnostics routine and select MISC TESTS.

Select A/T OUTPUTS-PC SOLENOID.

Increase the transmission fluid pressure by commanding low amperage. Read the corresponding line pressure on the pressure gage.

Compare your data to the Drive-Park-Neutral line pressure chart below. This line pressure is valid for PC solenoid overrides with the vehicle stopped at idle and in Park-Neutral.

If your pressure readings differ greatly from the line pressure chart, refer to Symptom Tables.

[BodybyFisher]

Here is a description of the Adapt Function. You can see why I thought of this with your symptoms. The adapts do not appear to be easily reset and a dealer might have to do it with a Tech 2

Adapt Function

The 4T80-E transmission uses a line pressure control system, which has the ability to continuously adapt the system's line pressure. This compensates for normal wear of the following parts:

The clutch fiber plates

The seals

The springs

The PCM maintains the following adapt parameters for the transmission:

Upshift Adapt - The PCM monitors the Automatic Transmission Input(Shaft) Speed Sensor (A/T ISS) and the Vehicle Speed Sensor (VSS) during commanded shifts in order to determine if a shift is occurring too fast or too slow. The PCM adjusts the signal to the transmission pressure control solenoid valve in order to maintain a set shift feel.

Steady State Adapt - The PCM monitors the Automatic Transmission Input(Shaft) Speed Sensor (A/T ISS) and the Vehicle Speed Sensor (VSS) after a shift and the PCM calculates the amount of slippage in that gear. The PCM then adjusts the signal to the transmission pressure control solenoid valve in order to maintain slippage below a set amount.

Garage Shift Adapt - The PCM monitors the Automatic Transmission Input(Shaft) Speed Sensor (A/T ISS) during a shift into a given range (P,R,N,D) and the PCM calculates whether the engagement is occurring too fast or too slow. The PCM adjusts the PC solenoid valve in order to maintain a set shift feel.

WOT 1-2 Adapt - The PCM monitors the Vehicle Speed Sensor (VSS) and the engine rpm during a 1-2 Wide Open Throttle (WOT) shift. The PCM will adapt the 1-2 shift point during WOT.

Learn Tap - Accelerated PLM learn mode. A technician must road test the vehicle for 15 minutes (normal time 2-3 hrs).

Important

The transmission may experience harsh, soft or mushy shifts for up to two days later.

Transmission adapts must be reset whenever the transmission is overhauled or replaced. In order to reset transmission adapts, select the following:

Scan tool

Miscellaneous test

A/T outputs

Clear or reset all adapts

[BodybyFisher]

Here is where the pressure tap is located, that is the leading edge near the side pan close to the ABS.

Line Pressure Adapter and Gage Installation

Tools Required

J 21867-94 Line Pressure Adapter Kit

J 21867-100 Pressure Gauge Adapter

Remove the air cleaner assembly.

Raise the vehicle and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.

Remove the Line Pressure Plug.

Install J 21867-100 using a ratchet box wrench. Tighten the adapter so that the insert hole for the dowel rod is in a 1 o'clock position.

Lower the vehicle.

Install the dowel rod from J 21867-94 .

Attach a line pressure gauge and hose to the dowel rod fitting.

Secure the hose in a safe position to avoid damage to the tools and vehicle during the line pressure testing.

When you have completed the testing procedure, remove the line pressure gauge and hose from the dowel rod fitting.

Remove the dowel rod.

Raise the vehicle and suitably support the vehicle.

Remove J 21867-100 using a ratchet box wrench.

Install the line pressure plug.

Lower the vehicle.

Install the air cleaner assembly.

[cyrez00]

Mike...

AAAAAAHHHHHHH!!!!!!!!

I'm almost at the point that i might just live with the occasional hard shift.....

However, will surely start asking around for someone owning a Tech 2 tool..

Thanks for all your input anyway! it's much appreciated and it gave me a LOT of food for thought.

Marc.

[BodybyFisher]

Mike...

AAAAAAHHHHHHH!!!!!!!!

I'm almost at the point that i might just live with the occasional hard shift.....

However, will surely start asking around for someone owning a Tech 2 tool..

Thanks for all your input anyway! it's much appreciated and it gave me a LOT of food for thought.

Marc.

No problem, I was going to say if its not too bad to let it go, the fix if you need to replace a pressure solenoid is a project as the side pan has to come off. If I were you I might try flushing your tranny a few times (I DO NOT MEAN MACHINE FLUSH), we have a method where we drain the fluid while the car idles with an adapter attached to the return line on the radiator. You get most fluid out this way. Do a search for the procedure, I actually made a custom adapter for it, but you can just buy a fitting with a nipple on it and use a hose. If you can reset the adapts that might help. You could be experiencing internal wear, but that does not seem to be the answer since you dont have the problem on WOT, which to me tells me that the LINE PRESSURE is high at 1/2 throttle maybe you have a sticking solenoid (although you would probably get a code), but I am just brainstorming here. Mike

[cyrez00]

Turned out that i'm able to reset the adapt function from the console (it's in the FSM!).

Did that tonight, got a P080 code meaning i needed to perform the idle learn procedure.

Did all the fun stuff (resetting 2 registers being P014 and P015) but hey guess what.... no change.

Decided to just live with it. the upshift is not to be called 'harsh' but i should call it 'less smooth' i think.

But... thanks for the ideas you gave me anyway, again i learned a few things about my car because of this!

[BodybyFisher]

Turned out that i'm able to reset the adapt function from the console (it's in the FSM!).

Did that tonight, got a P080 code meaning i needed to perform the idle learn procedure.

Did all the fun stuff (resetting 2 registers being P014 and P015) but hey guess what.... no change.

Decided to just live with it. the upshift is not to be called 'harsh' but i should call it 'less smooth' i think.

But... thanks for the ideas you gave me anyway, again i learned a few things about my car because of this!

Hey, it was worth a shot, good digging for the solution. Keep in mind that if you read above it says that when you reset the adapts it might be rough for a couple of days maybe it will compensate, drive it as you normally do and TRY to make it shift rough if you can,, Mike

[cyrez00]

Mike,

Turns out you seem to be right.

I notice a considerable increase on smoothness of the shifts.

the 1-2 shift i can't hardly feel at this moment. the 2-3 i feel is getting better as well but i haven't driven enough yet to get the car to sort itself out.

Had a strange one yesterday evening though.. i became to a point that it stayed in 1st gear and didn't shift at all anymore, the Service Engine light came on and gave me a P029 code.

Happened to have the FSM with me but that didn't mention the code at all, after stopping and starting the car again it seemed to have cleared itself and the shifts continued as 'normal'.

just checked and saw that was a shift B solenoid problem. seem to be ok at this moment though.

Will keep you up to date.

Marc

[BodybyFisher]

Hmmm, maybe YOU are right, maybe your shift solenoids are failing... Check your transmission plug, look for transmission fluid in it and plug and unplug it a few times to clean the pins. If the either side of the plug looks contaminated with coolant or tranny fluid, clean it with electrical contact cleaner...

You are a man after my own heart, having the FSM WITH you!!!!

[cyrez00]

Hmmm, maybe YOU are right, maybe your shift solenoids are failing... Check your transmission plug, look for transmission fluid in it and plug and unplug it a few times to clean the pins. If the either side of the plug looks contaminated with coolant or tranny fluid, clean it with electrical contact cleaner...

You are a man after my own heart, having the FSM WITH you!!!!

Great, you just gave me another challenge, trying to find this particular plug (from which i assume you mean electrical connector?)

The FSM's are even always lying on the passenger seat, nobody else sitting there anyway so it is their designated spot in the car

[BodybyFisher]

Hmmm, maybe YOU are right, maybe your shift solenoids are failing... Check your transmission plug, look for transmission fluid in it and plug and unplug it a few times to clean the pins. If the either side of the plug looks contaminated with coolant or tranny fluid, clean it with electrical contact cleaner...

You are a man after my own heart, having the FSM WITH you!!!!

Great, you just gave me another challenge, trying to find this particular plug (from which i assume you mean electrical connector?)

The FSM's are even always lying on the passenger seat, nobody else sitting there anyway so it is their designated spot in the car

Make sure the FSM has its seat belts on, it does not hold up too good bouncing off the air bags

Here is the location of the plug, its just opposite the ABS motor, near the front bank O2 Sensor.

[BodybyFisher]

Here is another shot, my plug had tranny fluid in it, I think what happens is that fluid leaks from the tranny and down the wires and into the plug, if you have wetness tie up the plug so that the fluid does not go into the plug

Here it is cleaned up

[cyrez00]

Thanks Mike, will have a look when i have the chance somewhere this week.

Let you know.

Marc.