coryforsenate

iTrader: (1)

I'd imagine you're correct, since the Fitzall would have to be sized for the OEM TCC bore.

But if you do the Sonnax reaming fix to maintain PWM, if you ran the transmission so many miles that the valve became worn again you should just be able to replace the kit with a new one because the Sonnax fix creates a new "bore" within the bore so that the valve body bore never gets worn. So just put a new valve kit in the already reamed bore that shouldn't have gotten any wear.

But I've read somewhere on here that having PWN on/off works better for high stall converters?

bbond105

You are correct. Sorry, I was thinking of this valve.
TCC Apply Valve Kit
Part No. 77805E-K

Jays_SSZ28

iTrader: (2)

Here’s a real-life example of a problem that came into our shop. A 1998 Chevrolet pickup with a 4L60-E was brought in with complaints of no reverse, no 2nd and no 4th gear.We figured this was a routine job. In fact, it’s usually a “gravy” job.We started the job by scanning for codes and found a P1870 and a P0300.

The P1870 (transmission component slipping) could have been the result of a stripped reaction shell, or it could have been a TCC problem. A quick look at the freeze-frame data on the scanner had us leaning toward believing the P1870 was being caused by the no 4th condition. Either way, the cause of no 4th and the TCC system were all going to get covered during the overhaul, so we figured we had that code covered.

P0300 is a random engine misfire code. Because we don’t specialize in engine performance, we noted the code on the invoice for reference only. Both P1870 and P0300 are common codes we see quite often.

A quick test drive verified the complaint, and our initial thought was that the problem was stripped reaction shell splines. We called the customer and received the authorization for an overhaul. Everything was going great, routine.We got it out and, sure enough, the reaction shell was stripped. So we did a basic overhaul.

When we got to the valve body – with the thought of the P1870 in the back of our minds – we ran a Wet Air Test and found the TCC regulator bore was worn, so we repaired the worn bore.

Everything was going fine and the customer called mid-afternoon to check our progress.With the unit ready to go back in, we told him that if everything went well, it would be ready the next day. That gave us plenty of time.

About 4:30 p.m. we filled it up with fluid and got ready for a test drive. After about 10 minutes I got word that the truck worked and shifted great. But ... it had no lockup. The technician said he thought he felt it lock up one time. What is it with 4:45 p.m. and no lockup? So I grabbed the scanner and took it for a test drive and, just as noted by the other tech, it had no TCC apply. I scanned for codes and there were no codes. I took a quick look at the TCC data and saw that the Vehicle Control Module was commanding the TCC enable: NO.

It was snapshot-movie time. A quick word on snapshot-movies: I feel they are the safest way to diagnose problems like this. (If you think talking on a cell phone and driving is dangerous, you should see how I drive with my nose rubbing a scanner’s screen.) So I took a snapshot and put it on the shop’s computer to study the data (see Figure 1). After several minutes of looking at the data I saw no reason to stop it from applying the converter clutch. The throttle position sensor, brake, speed, coolant temperature, rpm and any other data that could cause the VCM to not apply the converter clutch all looked fine (see Figure 2).


Being a little confused, I decided to go for a test drive and use the scanner’s special functions to bi- directionally override and apply the TCC to see if it worked. Sure enough, it did. I smashed the button on the scanner off and on several times as if I could teach the VCM to apply the TCC itself. I pulled over and put the scanner back into the monitor mode and there was still no lockup for no reason! What could I have been missing?

I shut the engine off and scanned for codes again. While waiting for the scanner to retrieve the codes, I looked at which codes we had written down before we started the work: P1870 and P0300. This P0300 now had my attention. As many of us know by now, a P0300 can indeed cancel the TCC apply. The scan still showed no codes. By the way, this scanner is a Tech2 running on GM software, so it is unlikely to miss a code.

I cranked it up and started back to the shop and noticed TCC engaged. I glanced at the scanner and, sure enough, the TCC Enable went to YES. But all the joy evaporated as I felt a slight engine misfire and the TCC Enable went back to NO. I drove it for about a mile or so and couldn’t get the TCC off to return to TCC on. I pulled over and turned the engine off and scanned for codes. Still no codes. I restarted the engine and took off and once again the TCC Enable went to YES and again I felt a little misfire and the TCC Enable went back to NO. So as I drove back to the shop, I performed the “clear codes” function even though the scanner showed “no codes present.” The TCC Enable went back to YES with the TCC coming on instantly. Now I was really confused. Why does TCC come back after clearing the codes, even when there are no codes present to clear?

I got back to the shop and made another tech get behind the wheel. I wasn’t sure if I needed another tech because I was all over the road or if I just wanted someone else to witness this bizarre event.We started the test drive by scanning for codes – again – and no codes were shown. At about 45mph the TCC Enable went to YES and the TCC slip went to 50 rpm or less, until we felt the engine misfire. At that point it seemed as if the VCM recognized the misfire and decided to turn the TCC system off to avoid more misfires. This was done without recording any codes, but the instant I cleared the “ghost codes” that weren’t there, the TCC Enable went to YES until it once again detected a misfire. I backed the scanner up in to the Misfire Graph Mode and looked to verify that what we were feeling was indeed a misfire. It was. But why wasn’t it recording any codes?

After several minutes of test-driving we determined that the software must have been written to turn the TCC off on the first few misfires without reporting and storing a code. If we continued to turn the key off and restart the engine and allowed it to go through the misfire cycle three times, it would report and store a P0300.

The fix was to replace a spark plug wire and eliminate the misfire. Once the misfire was gone, the TCC worked normally. We have seen this condition on several GM trucks. You can really chase your tail hunting the problem because once the engine detects the misfire and turns the TCC system off, the misfire goes away without the load the TCC puts on the engine.

Just keep my experience in mind the next time you have a GM vehicle with no lockup for no reason.

coryforsenate

iTrader: (1)

Thanks for the story, Jays_SSZ28!

Jays_SSZ28

iTrader: (2)

Not wrong, just have to read an entirely different thread from NOT the OP of this thread to get the information that the valve bore has been reamed.

Jays_SSZ28

iTrader: (2)

Not my write-up.
But this is my actual experience with misfires, no codes, and no TCC apply or P1870 code without P0300.

mntegra01

That is correct, I had the VB reamed by my local trans shop that had the tools, all I had to do was pay for the Sonnax valve. But now, I cannot go to a Fitzall or anything else unless I get a used untouched VB.

A few things here to note.....

I ordered my Sonnax Boost valve based off the old broken pump from transmission, so it was a late style. I went to put it in the other night and the valve I pulled was early style pump. Im guessing they are interchangeable are far as the basic pump goes, but replacing any part inside that pump has to match, the bores are different.

So I did not get my boost valve in, I talked to my trans shop again and they said to use the Transgo Boost valve kit. So I might go back and do that later, BUTTTT!!!!

I replaced the trans harness with the TCC solenoid made into it, replaced the PWM solenoid and Force Motor while I was in there. I went on a good long drive last night (40 miles one way and 30 the other way) and no codes or full pressure shifting. Before when driving It was getting to the point it would error within 10 or 15 miles and start slamming into 2nd, especially with the Vette Servo. I did notice right away driving home it seemed smoother, like maybe the pressure/force motor was working better?

I know replacing the electronics would not give me a 'fresh' trans like someone pointed out. Form me, it was a cheap option since I can get it straight from AC Delco cheaper. This trans did have 182,200 miles on it. Probably very worn out in many areas. I'll be honest, I did not replace the bushings, but If I ever need to go into the trans again, I will at that time. I had experienced guys at the shop just say, oh you have a bad case, gotta replace the whole thing, but no where in my research has led me to that conclusion. I replaced the 3rd checkball in the 2nd servo housing. maybe some guys dont even know its replaceable. I know one trans guy at our shop said 'what are you doing?' when I started with slide hammer and tapping in the new one.

So, I fixed my P1870 after a rebuild by replacing the harness and solenoids.

mrvedit

Glad to hear that the P1870 appears to be fixed.
To clarify, there are two Sonnax 4L60E boost valve models:
Sonnax 4L60E-LB1 - For years '94 thru '05 non-ISS - longer 1.907 length
Sonnax 4L60E-LB2 - For years '06+ ISS - shorter 1.810 length

Note: The change from non-ISS to ISS occurred around '05 to '06 but perhaps not the same year for all cars and trucks.

Only the length is different, the bore is the same.
Transgo deals with this difference by supplying a shorter boost valve and having you install the aluminum spacer for the longer earlier style.

mntegra01

​​​​​​
Thanks for the clarification, I was going off of the instruction sheets from Sonnax, But I will get the Transgo Valve or Sonnax that is correct for my transmission. But not sure what one is better if it even matters.

I had ordered the LB2 for my 03 and it was wrong. It is a non ISS trans, so you are right MrvEdit. As always, lol

-Cheers

mrvedit

Yup an '03 (non ISS) needs the LB1.

Here are the Sonnax instructions:
http://www.jegs.com/InstallationInst...-4l60e-lb1.pdf

One sentence is totally confusing: "Some late production, early-style pumps will use
the short boost assembly (4L60E-LB2)".
Best to look at their Figure 2 which shows the substantial difference between an early style and late style pump.
That is why I warned about checking '05 and '06 models carefully to ensure you get the right one. But anything pre '05 will be LB1.

clinebarger

They mean the ISS style pumps installed in Non-ISS vehicles such as '05/'06/'07 GMT-800 platform pick-ups. They were not machined for the ISS sensor early on & some of the late ones had plastic plugs in the ISS sensor hole.

EDIT.....You can machine a spacer to make-up the difference when using a LB2 in a '93-'04 pump body, More work than it's worth though!

mrvedit

Clinebarger: Always appreciate your taking the time to share your vast knowledge and fill in my gaps.