Pics of the GM trans PCS problem

[Flatrater]

This is a cut apart PCS.

[Flatrater]

Another view of the parts of a PCS.

[Flatrater]

Here is the business end of the PCS.

[Flatrater]

The PCS is in the closed position here. The last pic shows the PCS in the open position.

[Flatrater]

The picture text explains everything.

[Flatrater]

Here is where the damage is located at. Look close at the bottom arrow.

[Flatrater]

A close up view of the damage.

[Peter Solarik]

Thank you Flatrater for your extensive report, including the pictures of the culprit solenoid. You really 'bent backwards' to inform us more in detail about the hard shifting problems and how the trans works.
I took the car back yesterday and complained about the noticebly hard steering. The did not raise any objections, put the car up on the hoist and found what they did wrong during re-assembly. There is some ruber sleve which they did not positioned right and this sleeve was rubbing against the steering linkage (or something like that).
Took them two hopurs to correct it. (No charge of course). The car is back to easy steering.
I already gave them the welded covers. If I knew that the locations of the cracks would be of interest to you, I would take a digital photos of the 'Before and After' repair/weld. Just to satisfy your proffesional curiosity, I will go back there with camera and ask them whether they would not mind to take the pictures. I am afraid that they may be concerned and suspicious what are my intentions with the pictures. You understand.
I will try.
The owner too showed me the solenoid that they removed from my car. The needle was stuck even when he applied reasonable air pressure to it.
BTW,the crack was around the bolt hole, I had to cut (using a tool grinder) the whole area out, (about 1.5" around the hole - counterbore for the bolt), and slowly build up the cavity. Both cracked covers had almost identical hairline cracks in the same area. I see this as a weak point in the casting. If any of you guys are welding the aluminum covers and other componenets, get rid of the standard TIG machines. I was welding the covers with a new Miller Dynasty 300 series machine that allows you to set your pulses, HF intensity and you use 2% Thoriated Tungstens with the tip sharpened to the point ! This will allow you to put the heat exactly and sharp point to the spot you are welding. I am really impressed with this new welding technology. (Dont take this as an advertisement for Miller) (:-)
To make the long story short, my car is fixed, and I hope that the transmission will be free of trouble for at least next 30.000 miles.
Therefore I am trying to keep a good realtions with the shop that done the repair - not knowing when I will need them again!
Next time I will charge them for the welding job.

[BNaylor]

Originally Posted by Flatrater

This is a cut apart PCS.

Nice pics Flatrater. I know one of the symptoms of a defective PCS solenoid is harsh shifting. Another audible sign may be a whining sound. Is this due to leakage or the system going into a bypass mode due to high line pressure, etc?

Last question, do you know of any emissions type odb-ii DTC error codes that will trigger the ECU to command high line pressure even with a known good PCS solenoid and no other known mechanical problems with the tranny?

[Peter Solarik]

Hi Flatrater:
I phoned the owner of the trans shop where my car was repaired and explained to him that one of the forum participants/adviser would like to see where the cracks originated. He said, no problem, come and take pictures. How do I go about it? How do I send the picture attachments? To the web site or you personally? I will keep the resolution down to 40 - 60 KB (faster do download or emailed).. No more than 4 - 5 pictures.
Check my response to you also in thread 'To Flatrater, Bnaylor and alll our advisers, (Hard shifting) '.
One more question:
Since the steering unit had to be 'disturbed' will this affect also the front end alligment? The shop said - no.
Thanks again for all your assistance.

[Flatrater]

Originally Posted by Peter Solarik

Hi Flatrater:
I phoned the owner of the trans shop where my car was repaired and explained to him that one of the forum participants/adviser would like to see where the cracks originated. He said, no problem, come and take pictures. How do I go about it? How do I send the picture attachments? To the web site or you personally? I will keep the resolution down to 40 - 60 KB (faster do download or emailed).. No more than 4 - 5 pictures.
Check my response to you also in thread 'To Flatrater, Bnaylor and alll our advisers, (Hard shifting) '.
One more question:
Since the steering unit had to be 'disturbed' will this affect also the front end alligment? The shop said - no.
Thanks again for all your assistance.

All the pictures I attached here are located in the AF gallery. If you look at the top of the page you will see the headers 3rd one form the left is the gallery. Just sign in and you can upload the pics.

Moving the steering gear will not effect the alignment enought to worry about it but removing the engine cradle will change your alignment specs. GM recomends doing a front end alignment whenever the engine cradle is distrubed. If you loosen all of your cradle bolts and move the cradle forward or aft will change your caster angles. Moving the cradle side to side will change your toe and camber angles. All GM engine cradles have holes in them that line up with holes in the body. I always make sure to line up the cradle to body holes and then align the suspension.

If you want call an alignment shop and ask them if moving the engine cradle can change your alignment specs.


Also Peter you said the shop showed you your old PCS, showing you how the needle was stuck. Now how would low trans fluid level cause a needle to stick? It can't!

[Flatrater]

Originally Posted by bnaylor3400

Last question, do you know of any emissions type odb-ii DTC error codes that will trigger the ECU to command high line pressure even with a known good PCS solenoid and no other known mechanical problems with the tranny?

I would have to read every code to find out what codes would command high line pressure to be sure. But off hand most of the trans codes will default either to a high line pressure or default to a second gear start. For instance on some Buicks a bad alt will default the trans into second gear start. If you want I can research what problems will affect the trans when I have time.



Hey Peter I am rebuilding a 2003 GMC Envoy trans that was low on fluid. The only damage wa to the friction material to the clutch packs. This damage only happened after the trans was one gallon low on fluid.

[bignoisey]

Thanks Flatrater for the pics. Like they say, they're worth 1000 words. So it looks like the groove that's worn in the solenoid's armature causes it to hang up in the low current/high line pressure state which causes the jerky shifting. On my car this seems to happen only when the car is thoroughly warmed up and will remain until it cools off.
You describes somewhere that the PCS can be changed without removing the transmission and only lowering the cradle. I'm almost ready to try this myself on my 2000 Century. If I remember the time I changed a FWD transmission on a GM, you'd only have to disconenct the steering, the struts, and a couple of engine mounts. How about engine hoses/cabling? That may be possible with what I have to work with (basically, a floor jack and standard mechanic's tools). Does removing the side cover require draining the fluid first? Is the PCS exposed once the side cover is off? Any other pitfalls? Once I start, I won't be able to move it easily.
One more thing, I had a couple of instances of my TCC malfunctioning I think the code was P0742 TCC System Stuck On. That caused really rough shifting. This seemed to clear itself both times, but happened on a road trip in both cases. Could the PCS problem have anything to do with the TCC? Any advice is welcome.

[Allbert]

Originally Posted by Flatrater

This is a cut apart PCS.

Flatrater, if you wouldn't mind, I'd like to use some of the pictures you've posted in this forum in some marketing material. I work for BorgWarner, and we are about to launch an aftermarket PCS of our own design as an alternative to the OE PCS (made by Delphi). The pictures you've taken illustrate the Delphi design weakness very clearly, and since I couldn't do any better if I took pictures myself, I'd rather use your material and give you the credit. Please let me know if this would be OK with you.

Thanks.

[Flatrater]

Originally Posted by Allbert

Flatrater, if you wouldn't mind, I'd like to use some of the pictures you've posted in this forum in some marketing material. I work for BorgWarner, and we are about to launch an aftermarket PCS of our own design as an alternative to the OE PCS (made by Delphi). The pictures you've taken illustrate the Delphi design weakness very clearly, and since I couldn't do any better if I took pictures myself, I'd rather use your material and give you the credit. Please let me know if this would be OK with you.

Thanks.

I have no problem in you using these pictures but I am not the owner of these I just copied them from a friend of mine who did all the work. I am sure he wouldn't mind you using them. I also perfer not to get the credit for them. If you want I can email the person who took those pics and ask him if he wouldn't mind.