Performabuilt 4L60 with Circle-D 278mm single disk (non billet) 3200 converter with 4.10 gears. 2000 GMC 2wd single cab SBE LQ9 H/C/I and 150 shot.

Changed the fluid & filter last month at 20,000 miles on the transmission. The fluid was darker than expected which of course gave some concern. A few days later cruising normally at hwy speed I could feel the converter unlocking and locking around 60mph which it's never done before. Two weeks ago after a rolling nitrous hit the P1870 code triggered. Cleared the code in HP Tuners and this weekend during normal hwy driving it re-triggered the P1870... cleared and again re-triggered.

I'm thinking the converters clutch is worn causing slip and triggering the code. It's the budget Circle D converter and I've done a lot of 4th down to 2nd and back up through the gears WOT pulls. The transmission still shifts with no slippage and feels good. It's my understanding Performabuilt eliminates the PWM during assembly.

With the dark fluid would it be a bad idea to only replace the converter with a billet triple disk and hope for the best? Performabuilt offers a $1200 rebuild on out of warranty 4L60's but at the moment my budget is low at $2,500 which is short for both the rebuild and new converter.

I have the trucks original 4L60 to use while the built transmission is getting refreshed. I'm thinking maybe try to limp around with this old trans and worn Circle D converter for another month, until I have the funds for the rebuild and new converter. Can the P1870 DTC be disabled and the shift tables be adjusted to eliminate lockup in HP Tuners while I nurse the old stuff for another month? The truck is only driven twice a week is is my daily (retired old guy).

Fluid color after change (New vs Old)






Attachment 712198

 

There was a lot of problems like this that was discussed with live tranny dissasembly by Ryan @performabuilt
All of theyr trannies was in brand new condition durning that.
and yes, they get rid of pwm. Theyre valve body setup is unique.

My bet is that your TC cant handle the power.
Ask Frank or Ryan for a good recommendations for a TC or you can direcly ask @FTI Converters and @Circle-D for a good solution.

Btw, even your old oil doesnt look bad and honestly, i dont think you need a rebuild. Just swap converters.

 

With your torque converter being non billet there is a good chance that the torque converter clutch has worn out. If you wanted to just replace the converter, I think that would work out just fine as long as the fluid does not have a lot of debris in it. Just be sure to blow out the cooler line and cooler.

Before buying a high dollar billet triple disk converter and still have the same problem you could install a known good stock converter, (if you have one), to verify that the problem is actually the TCC.

As long as you are not applying the TCC under WOT a billet single disk converter should meet your needs.

 

Thanks for the replies.

I've filled out the "Ask Circle-D" form on their site with all my specs to get their advice on the new converter. The triple disk upgrade is $330 and may go that route for piece of mind.

After some research I've read you can't disable lockup in the tune as It will cause over heating issues. I know the P1870 code disables lockup and haven't seen any heat issues on the trans temp gauge. That confuses me somewhat... if the P1870 code disables lockup why am I still seeing normal temps? I do have the huge 40K Tru-Cool cooler that's bypassing the radiator.

Normal hwy driving temps with the P1870 code



Cooler from Performabuilt that came with the trans



Upgraded to the Tru-Cool 40K

Attachment 712261

 

Brian from Circle-D recommended the triple disk 258mm Pro Series 3,600 stall.
Just ordered with a 4 to 5 week build time.

Now to pull transmission and get it back to Performabuilt for the refresh.

 

The P1870 code has not triggered for about a month, trans is shifting great so I'm thinking it was converter related. Maybe the single disk converter ballooned on the nitrous hit and somehow retained it's shape enough to no longer trigger the clutch slip code.

What is the best way to drain any residual fluid after pulling the transmission?

The 258mm arrived today so it's time to get to work!

 

 

That P1870 can trigger for a variety of reasons. Its simply the PCM determing that engine RPM/ trans input speed (if applicable; newer 4Lxx trans) isn't matching what it expects for a given gear range/ command. It then infers that something MUST be slipping. For example, I found a 4th piston servo seal (the little aluminum disc piston in the 2-4/ "Corvette servo" assembly), had a torn scarf seal causing a slip in 4th only. I couldn't tell when driving, but when monitoring scan data, slip speed would increase in 4th only, which indicated to me there must be an issue with that piston assembly (or god forbid, the hydraulics somewhere). If you haven't already, you should try to isolate when/ why that code is triggering. Also, every time you make a tune change in HP tuners, it can be treated the same as CPS or PCM replacment from a repair standpoint meaning: you should perform a Crank Angle Relearn. The erroneous TCC unlocking can be caused by a false P0300 after a tune write, or the above mentioned component replacment.

 

The P1870 triggered coming off of a nitrous 2nd to 3rd pull... off throttle... coast... 4th... "trigger code". The last month it's back to normal no codes even under WOT shifting... no nitrous hits though.

 

Time to get to work

 

The best way to drain any residual fluid without taking the trans apart is to flush the trans or do a filter change start the engine run the trans through all of the gears, then dump the fluid and refill. This won't get all of the old fluid, but it will get a good bit of it. I do this whenever I get a lot of metal in my personal torque converters.

 

if you send metal through things...just take it apart
this is silly

would you smoke a rod bearing and send metal through your engine, then just knock a new bearing in it, change the oil, and keep on rollin? no
I mean...I would at a race to make the next round...but not on a street car like we're discussing here

flushes and fluid exchanges etc is not the proper way to deal with a converter failure sending metal through the trans. Just my $0.02
If you elect to do it that way on your own, that is fine. I don't have any quarrel with that. Just so long as you're prepared for whatever damage may or may not occur as a result. it may be fine for another 100k. It may cause a bunch of headaches and issues down the road. If you're good with that than OK

 

I agree and appreciate your post.

All I found in the pan was the usual silver goop on the magnate. I felt carefully for small pieces of metal bits and found none. I'm thinking I may have ballooned the OEM stamped cover with numerous 7000 RPM nitrous hits. From my understanding when the cover gets distorted like that only the very center of the lockup clutch material makes contact... then slips... then triggers the P1870. The truck still smokes the tires through 1st 2nd and into 3rd with no slip. Normal driving each shift feels firm as the day it was built.

I understand I'm rolling the dice here... hoping for the best.

 

Converter spacing was in excess of the maximum 3/16"

How the heck am I going to get those shim washers between the flexplate & converter??













Worked well without dropping and fishing out shims.

 

Cooler flush came out really clean