Default Still having pronounced shudder issues"Is anybody out there?(for Floyd fans, lol).

Still having pronounced shudder issues in my '95 3.4L that sat for 13 years. But, ONLY after 45 mph and above & ONLY after overdrive lowers rpms above those speeds.

I replaced tranny filter and cleaned a relatively spotless pan last fall but only drained old fluid out and added 2 tubes of shudder fix w/ minor improvement. So, after winter pause, I'm back at it. I just flushed 8 more quarts through dipstick (2 at a time) to get TC flushed a bit to start the spring off.

My last ditch effort b4 replacing converter will be replacing PWM solenoid, TCC solenoid & all the others since I'm in there of course. The service manual excerpt pic below says to check TPS and other electronic parts first. My tranny shifts very smoovely through ALL gears so I don't know if replacing the coolant sensor & the others would help in my case. I don't even think the solenoid replacements will help but the TCC PWM & the other TCC solenoid failure symptoms sound more relevant to me.

Thoughts on both TCC solenoids fixing shudder? Also, the solenoid kits make $ sense but should I stick with ACDelco or is there a decent non-OEM kit I can use?

Thanks gents.
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That makes me suspect the problem is the TCC lockup. Especially since you say it sat a while. Maybe the lockup clutch didn't like that.

Replacing the solenoids shouldn't hurt anything, except the wallet. Your thought process makes sense to me.

 

Thanks Green. Wow, <24 hrs for a reply on here. Last time I think I waited a week lol. It's sad what a ghost town these forums have become .

Do know if there's any useful data on garydoug's scan9495 app, or ANY scanner for that matter, that may help pointing to TCC issues? Not necessarily even direct or definitive data but perhaps peripheral data somewhere in the app that points to a bad or faulty TC?

 

I am relatively new here myself. I joined because this place came up somewhat often in Google searches and when I looked at recent posts they were at least from this year. But yeah, it does seem like there like three relatively active users and a bunch of one-time posters screaming into the void about their one problem they are working on...

If this is what I think it is, I kinda doubt it.

I am not a transmission expert, but I know a few things about wet clutches from motorcycles. I know that a clutch friction plate can change how it grabs when sitting a while. I also know that if you have a plate sitting half in and half out of fluid might get uneven. So, if it sat a while and fluid was low, the lockup clutch might slip and do so unevenly.

Don't take this a gospel, tho. Like I said, I am not a transmission guy.

 

Thankfully, last summer when I took the first two quarts out and changed the filter, the tranny fluid actually looked really good, zero clutch material or metal specks. I felt so lucky. Until..I took it up to 45-50 of course and felt the shudder. Its seemed so counter-intuitive to think of a clutch or similar friction material operating normally in liquid until I inherited an old JCB backhoe with "wet" brakes. .I'll have to replace the TC on my back in a gravel driveway so I'm not looking forward to dropping this tranny. Solenoids should be here next week so wish me luck bruv.

 

So... I was just thinking...

If you have a scan tool that lets you command functions in the drivetrain, you could potentially make it not lock up the converter. If the shudder isn't there, then you know it's the lockup.

Otherwise you can see if the shudder happens right when it locks up.

I would do that kind of thing with two sets of ramps. Drive up on one, then jack up the other side and slide the other set under the wheels. It should be the most solid way. And get a sheet of plywood or something to maneuver the jack with the transmission on it.

 

Funny you said that cuz I was just reorienting with the scan9495 earlier and I saw that option/function I think. And, thanks for the tips. I forgot to mention my driveway is on about a 7-10 degree incline also so I end up stacking 16 cinder blocks (2x2 stacked under each wheel) when I need a lot of elbow room. Getting it up that high took a bit of planning and It's prolly overkill but I definitely feel safe under there.

 

I have a couple more considerations (for now):

Most importantly, given that I don't have a Tech II, do you know if I need a scanner for the pcm/ecm and gm software to recalibrate the data when I replace the solenoids? I only saw reference to reprogramming them on a video or two but most vids just slap 'em in and refill the tranny. I thought the ecm just adjust the new parameters itself, like it does after disconnecting battery.

Also, replacing the PCW solenoid may not matter if it should be modified or bypassed anyway. Given the 4L60e PWM disaster, modding/replacing it is a no brainer. The decades-old Sonnax HP-4L60E-01 Performance Pack seems like a better mod than just notching out the solenoid. The TRANS-GO HD2 shift kit looks even better.

I know the irony here is that none of this will prolly help my shudder issue. However, even if the solenoids don't help, the old ones were 126,000 miles old. And, protecting the clutches in a new TC with the mod(s) in place is another no brainer.

 

Hola three amigos. Do any of you know how to "reprogram" the ECM on my '95 3.4L Camaro. Evidently, when I swap my TC shuddering, PWM-equipped, '95 4L60E out with my, parts only, '94 (non-PWM) tranny, I have to program the ECM not look for or just forget that the PWM isn't there. And, change the % values when the TC locks up.

Someone posted these 3 potential fixes a long time ago; 1. reprogram PCM so it doesn't look for the PWM solenoid, 2. swap the '95-96 harness into the car ALONG WITH the PWM solenoid connected but leave the solenoid in the pan, 3. wire up a manual TCC lock switch by which you can lock the converter.

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Otros advice:
https://forum.hptuners.com/showthrea...you-delete-PWM
⦁ Setting the TCC duty cycle tables as I described fixes the TCC PWM. Your TCC duty cycle will now be either 0 or 100%. Works great!
⦁ Block the 3-2 downshift and 3-2 control valve
⦁ Flip the inner valve in the TCC lineup
⦁ Then just run whichever solenoid matches the year of the ECM
⦁ That's all you need to do to make any of these years work together.

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More advice:
Putting a 96 trans in a 94 is easy:
⦁ Just block the valves as stated above.
⦁ Use the 94 3-2 control solenoid.
The ECM doesn't do any more than a circuit check on the solenoids. So it can "tell" between an on/off and a pwm based on the resistance and amperage draw...but that's all it can tell.
So, blocking the valves takes them out of the equation. Using the right solenoid makes sure the ECM doesn't get pissed off. You'll be all good

Also...if you want to put that 94 into a 96...just use the 96 harness and since the 94 doesn't have TCC solenoid...just leave one plugged in and dangling in the pan...or zip tie it so it can't move. But just having that solenoid there for the circuit is all it takes to make the ECM happy
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*4L60E year differences and interchanges
UPDATE BELOW: SWAP IS POSSIBLE!
None of the '93 -'97 4L60E's are directly interchangeable, except '93 and '94 and '96 and '97!!! Here's a list of yearly differences that will show you why. Yes, some years will fit in others and may not even throw a code, but there will be an issue in the long run. The big issues become forced 3-2 downshifts, and converter lock up issues and burnt lock up clutches. When a converter cluych cause it to lose lock up, the 3-4 clutches, in the transmission will soon follow because the 3-4's need lock up to keep them cool while cruising in overdrive.

1993: These were used in TRUCKS only. Not available in F-Bodies, B-Bodies, or Vettes

1994: Interchangeable with '93 4L60E with no modifications. The '93-'94 is a NON PWM transmission. This means that the lock up apply strategy is an on /off arrangement. It has an 11 pin case connector. Does not have PWM cast into front pump. 1 piece TCC control valve in the valve body. Plate has holes in plate, marked in diagram below. 1st design 3-2 valve

1995: Stand alone year! Will not interchange with any other year. This is a PWM transmission. An extra solenoid was added to the valve body to control the pulsed lock up strategy of the conerter clutch. It has a 12 pin case connector, extra wire in the transmission to computer harness and different computer to control the new PWM circuit. Has PWM cast in front pump. Front pump internal passages different to match new TCC strategy. 2 piece TCC control valve in valve body. Has holes in plate, marked in diagram below. 1st design 3-2 valve. 12 pin case connector. '94 computer won't recognise new TCC strategy., and will burn lock-up clutch and 3-4 clutches up. '96 computer isn't compatible with '96 3-2 control solenoid.

1996: The 3-2 downshift strategy was changed to an on /off arrangement. The 3-2 downshift solenoid was changed to a 20-31 OHM solenoid, from the previous 10-15 OHM solenoid. The 3-2 control valve was changed to the second design valve. The easiest way to identify the valve is, the second design valve will fall out as soon as the solenoid is removed. The first design has a plug and retaining clip. TCC solenoid remains 10-15 OHMs, which is the same as the '95 arrangement. Has PWM stamped cast in pump. pump is the same as '95. Will not interchange with '95 unless changing 3-2 solenoid, valvebody casting, and seperator plate. Has holes in plate marked in diagram. '94 or '95 computer will not accept the 20-31 OHM 3-2 solenoid and will throw an SES light and throw the transmission into limp mode. Some less knowledgeable builders will swap the solenoid so the computer will see the correct resistance, but the valve itself then causes downshift issues. If only the solenoid is changed, it will result in a 3-2 downshift cut loose. In other words...3-neutral-2 downshift. Speedo moved to passenger side of tail housing, but easily changed.

1997: Basically the same as '96.

*** ADDITIONAL INFORMATION***. We have found that the '94 and '95 cars share the same part number for the PCM. This means that the PWM function is part of the tuning. It appears as though it's possible to install a '94 4L60E in a '95 vehicle as long as the PCM is reprogrammed to delete the PWM function. A '95 can be installed in a '94 as long as you add a wire into the trans harness that connects the PCM PWM pin to the transmissions PWM pin. The pin is pin 6 in connector d, the blue connector on the PCM, to pin U on the trans. This ia a brown wire on 95's.
Last edited by CPT; 07-06-2015 at 03:57 PM.
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If you want to disable the PWM function on your 1995 Camaro PCM, specifically regarding the torque converter lockup, here's how you can do it using tuning software like HP Tuners:
Access the TCC Duty Cycle Tables: In your tuning software, locate the settings for the TCC (Torque Converter Clutch) duty cycle.
Adjust Duty Cycle Values:
Set the TCC duty cycle max table to 100%.
Set the TCC duty cycle min table to 99%.
Save and Flash: Save the changes to your tune file and flash the updated calibration to your PCM.

Important Considerations:
⦁ Potential Side Effects: Disabling the PWM lockup can result in a more abrupt engagement of the torque converter.
⦁ You may need to raise the TCC lock-up speed to mitigate potential low RPM surging or bucking.
⦁ Valve Body Condition: If your transmission has high mileage, the valve body bore might be worn, which could affect the TCC lockup even with a disabled PWM. Consider checking and addressing any potential mechanical issues in the transmission.
⦁ Professional Assistance: If you are unfamiliar with PCM tuning, it is highly recommended to seek assistance from an experienced tuner or a transmission shop. They can help you properly tune your PCM and address any potential issues.
⦁ Note: This procedure specifically addresses disabling PWM for the torque converter lockup. If you are interested in disabling other PWM functions, the steps may vary.

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