99pewterZ71

iTrader: (3)

I have a buddy that I'm helping (bluestreak98) with his 4l80e swapped turbo 5.3 2000 camaro ss. The PCM seems to want to lock the TC almost all the time even though in the tune as far as I can see it should not be until 40 mph in 3rd gear. In the log it shows TCC “yes” once moving. I made a log and it showed "TCC apply" pretty much as soon as it started moving. I don't know if this is showing “yes” because it is locked or if its showing yes because its commanding it to be locked.(chicken or the egg what came first?? haha)

It will shift the 1-2 and then lock (feels like a double shift) and same with the 2-3. It appears to unlock during the shifts and relock once in gear creating a double shift feel. It’s not shown in the log above but when I commanded the TCC PWM or TCC solenoid off it didn’t seem to unlock (not sure how that works on a 4l80e tune) I bumped the PCS manually to 20% temporarily and the shifts became very firm (good) and it seemed to stay locked through the shifts now as the double shift feel was gone but the rpm drop was quite a bit due to no slippage.

The car is throwing a P0748 but I don't know if that could be from my forcing the PWM to a higher %? Could this code be causing the TCC to apply? It has a pretty loose triple disc circle D that takes 1400-1500 rpms or so before it really starts moving. I don't know if the car may have a bad TCC solenoid or something mechanically wrong. It doesn't apply in first gear since the fluid path isn't open during 1st, which makes me lean toward a electrical issue more than a mechanical. It has a speartech harness and has been segment swapped. It has a startup tune by a very reputable tuner. Thanks!

LilJayV10

iTrader: (39)

Does it do it all the time or just after it's warmed up? Does it ever lock up at idle?

99pewterZ71

iTrader: (3)

seems to do it all the time. It's never tried to lock at idle or in 1st gear although the log shows it being called for in 1st. The log is a pretty bad one as it's just a quick log through his neighborhood but I'll try and post it up when I get to a computer.

99pewterZ71

iTrader: (3)

Attached is the log where it shows "TCC apply" at pretty much anytime the car is moving

1bdbrd

iTrader: (12)

Not sure if you fixed the issue or not but a friend of mine had the exact same issue with his 80e swapped Silverado with a triple disc Yank converter. He had to install some special valve to control the fluid pressure. I am at work so I can't watch the video but I believe this explains it in more detail:


Swapped that into my friends truck and it worked great with a proper trans tune.

truckdoug

iTrader: (26)

the TCC apply enable doesnt mean the TCC solenoid is activated, it just means that parameters are right that it can be activated. can you drive it and command it on and off?

and usually you only end up with that clutch stuck on problem if you mechanically alter the pressure relief valve in the pump without drilling the little bypass hole as per the HD2 kit instructions

Compsystems

can you post the tune so we can see what its commanding?

Also as Truckdoug asked, can you manually force unlock in VCM scanner?
That will rule out any mechanical issues.

LilJayV10

iTrader: (39)

I didn't watch the video but a common problem with the 80's is that at idle/low speed, there isn't enough fluid volume to keep the TCC unlocked.

There are several "fixes" for this with include raising the idle speed, drilling a hole to allow more fluid to the TCC circuit or change a valve in the front pump.

Also if there is a restriction in the return of the trans cooler will cause it too.

I just went through this at the shop from a "big, well known" trans builder. I kept telling him there was an issue in the trans and he kept telling me it was an electronic issue.

After I disconnected the plug to the trans and it still did it. He said to send the trans back to him. Well wouldn't you know it, his "builder" didn't bother to do the fix they always do.

SMH.

99pewterZ71

iTrader: (3)

Thanks for the replies guys. I didn't get notifications that I had any more replies so this is all new to me this morning. I pulled the valve body and installed a new separator plate and replaced the pressure control solenoid and tcc solenoid and the trans is doing everything right now except its locking when getting heavier into the throttle. 2nd gear and easing into the throttle will make the TC lock, same in third even though the tune has it programmed to not lock until 4th and only under light load areas. Any ideas on this? I hate to sound incompetent but I built the trans over 2 years ago and am pretty sure I drilled the relief in the pump to help with TCC clutch dragging but Im not 100% sure. If this was the case wouldn't the issue be more at idle? When it locks while easing into the throttle its a very firm lockup.

wht/73

Wouldn't the dragging only be at idle?
Also what's " low" idle speed that this would happen?

99pewterZ71

iTrader: (3)

that is kind of what I was thinking. Are there any other codes that need to be turned off when doing a segment swap that could cause the tcc to apply if its sensing tcc slip? P0101-103 are turned to disable. There are no codes on the car other than the gas gauge.

99pewterZ71

iTrader: (3)

What happens if the hole was drilled in the pump for the charge circuit in the TCC and I install the 34200-14K valve as well? I don't want to damage his triple disc converter.

wht/73

Pretty sure it's one or the other. I had the latter done.

99pewterZ71

iTrader: (3)

Just to update for anybody doing a search we finally figured it out. We have suspected a segment swap issue for a long time now but not being extremely knowledgeable with hptuners I wasn’t 100% convinced, but we were running out of options. I started reading and the OS From his Camaro was 936036 which it turns out GM never made a 4l80e truck with that OS so it seems to be hit or miss using a same year different OS segment swap. Luckily he owns and daily drives my sisters old 2000 Z28 that happened to be unlocked and had a different more common OS 9360361 which we easily found a matching OS. I transferred all the tune setting over after completing the segment swap and did a “write entire”. And bingo. The trans works perfect and the TCC acts as it should. Hope this can help somebody in the future.