DIY transmission fix

I've recently purchased a 99 Silhouette. It had most of the problems I see posted in these pages and I knew what I was getting into, but still the price was right.

I'm ready to tackle the transmission issue next. It has the whine & shift hard symptoms I've seen lots of posts about. The trany is th 4T65e which is the only one for the 99 model, don't know about other years. It sets the code for the TCC valve stuck once in a while, but not often.
I've installed an extra transmission cooler and that helps a bunch but I'd like to get that TCC valve replaced
I plan to purchase the valve and install it myself. I've read this is not too bad of a job but wondered if anyone else has done this? The driver's wheel and shaft need to come out, the frame bolts need to come out, the engine needs to drop and roll downward, etc. Anyone been here or am I on my own?

Sonnax.com sells the valve body repair kit and reaming tool, this is a fairly complex job, make sure you want to do this. Also it should be scanned with a trans capable scanner to check for codes and confirm actual tcc slippage that is traceable to the tcc valve bore being worn, there are other conditions that could set code p1870 which usually associated with the valve body issue.

I certaintly don't want to do this, but its either I do it or it won't get done. There is just no money in the hat!

The code I get is 0742, which is TCC valve stuck on. Couldn't remember the code on my 1st post. Anyway, thanks for the tip on sonnax. Unfortunately, I couldn't find the 4T65-E transmission on their site. I've located a source for the valve, and an axle seal (small leak on left side) and it was my plan to replace just the TCC pwm valve.
Have you had any experience with this proceedure? Perhaps I'm naive, but once I lower the engine down and expose the side cover I was thinking it might be pretty straight forward to replace the TCC valve. Any tips anyone might have would be welcome.

Just a difficult messy job to access, make sure you know exactly which solenoid you are looking for once apart, try and get some kind of shop manual for exact procedures and precautions. Look for debris in the solenoid or bore for the TCC valve, keeping in mind the worn vb bore for the valve can also cause it to cock and not release, but 1870 would normally accompany that condition.

I certaintly don't want to do this, but its either I do it or it won't get done. There is just no money in the hat!

The code I get is 0742, which is TCC valve stuck on. Couldn't remember the code on my 1st post. Anyway, thanks for the tip on sonnax. Unfortunately, I couldn't find the 4T65-E transmission on their site. I've located a source for the valve, and an axle seal (small leak on left side) and it was my plan to replace just the TCC pwm valve.
Have you had any experience with this proceedure? Perhaps I'm naive, but once I lower the engine down and expose the side cover I was thinking it might be pretty straight forward to replace the TCC valve. Any tips anyone might have would be welcome.

If you're asking about how difficult it is to replace the PWM solenoid once you've got the side cover off, it's a piece of cake... the connector pops off easily and the springy clip that retains the solenoid in the valve body is easy to get out and back in too. Getting the side cover off is the hardest part. One tip, I would not even consider doing all this work unless you were also going to change the PCS... these things are notorious for wearing out early, so if you're going to be in there anyway, I'd definitely spend the $29 (gmpartsdirect.com pn 10478146) and take care of it too.

Ok, but what is a pcs? I've got the helm's books but not here at the office. As I recall, there are about 6 or 7 various valves in there and I'm not registering in my mind one called a pcs valve; I'll have a read again tonight.

Thanks for the tip on gmpartsdirect. I located a transmission parts house (www.bulkpart.com) that shows the tcc valve, but I had no way to determine the gm part number for it so couldn't order from gmparstdirect.
Is there another source to find part numbers? Helms manual doesn't seem to call out very many part numbers at all. It be nice to match up the item in the manual to a gm part number somehow.

Ok, but what is a pcs? I've got the helm's books but not here at the office. As I recall, there are about 6 or 7 various valves in there and I'm not registering in my mind one called a pcs valve; I'll have a read again tonight.

Thanks for the tip on gmpartsdirect. I located a transmission parts house (www.bulkpart.com) that shows the tcc valve, but I had no way to determine the gm part number for it so couldn't order from gmparstdirect.
Is there another source to find part numbers? Helms manual doesn't seem to call out very many part numbers at all. It be nice to match up the item in the manual to a gm part number somehow.

PCS = pressure control solenoid. It is the part that control the line pressure in the transmission. The original equipment design from Delphi has a soft steel armature rubbing against a hardened steel bearing, so the armature gets a groove worn in it quite quickly. The groove catches on the bearing and keeps the part from regulating pressure correctly.

There is a link from the gmpartsdirect website that goes to a separate catalog site... this site has exploded views of systems and will allow you to find part numbers.