Have you noticed any automatic transmission fluid leaking from the 4L60E?

I ask because, often powertrain control module diagnostic trouble codes P1870 and/ or P0741 will present should a leak from the transmission pump assembly bushing/ front seal occur. (as well as many other potential causes).

Both the P1870 (NON-specific slip detected, torque converter clutch stuck not applied) and the P0741 (torque converter clutch stuck not applied, four gear TCC slip) may be stored in the history diagnostic trouble codes in the GM Tech Two diagnostic tool. Also look at the freeze frame information stored at the event of setting the diagnostic trouble codes. Get us some more information please. When an intermittent problem occurs, this would be the best course of action.

Now getting back to the transmission having an automatic transmission fluid leak...
When automatic transmission fluid leaks at this location, a significant loss of ATF flow and pressure occurs and the torque converter clutch apply valvetrain will not move to apply the lock-up clutch in the torque converter. In this scenario the ATF leak would be from a worn pump assembly bushing or simply a pump housing front seal that no longer functions properly.
There is also an O-ring on the turbine shaft that can cause a leak between the apply and release sides of the torque converter clutch circuits.

It is also possible that the torque converter clutch regulator valvetrain that you installed from SONNAX is not installed correctly is creating a leak.
When the transmission control valve body is drilled for the new torque converter clutch regulator valvetrain, there is risk for error.
The new parts must have a precision fit in the bore and sleeve.

The other possible causes to the P1870 are less likely base solely on the information you have provided thus far.
More information from you would be helpful in aiding you to a solution.

 

Ok so I have done some more troubleshooting.

It turns out the tcc is not locking at all. The freeze frame data shows the TCC slip as 300rpm after the tcc is commanded on, which explains the code.

It sounds like the tcc regulator valve is the first thing to check, as is the o ring on the Input shaft. Is there anything else I should be looking for initially?

There is no visible fluid leak of any kind.

 

The amount of times I've seen someone do a bad ream-job and end up with a bore just as bad as they started would surprise you.

Vacuum test the valve body.

But I'd check the wiring at the trans first and foremost.
You have the TCC pwm solenoid but that doesn't do all the work. You also have the TCC on/off solenoid.
Both have to work in conjunction with each other.

Ensure they are both functioning properly before taking drastic measures.

Also...do a pressure test in all gear ranges and while driving even. See if you can pick up any anomalies

 

The TCC on/off solenoid (the one bolted in the pump) is easily replaced if needed and there have been several posts about them going bad.

Unless there is a problem with the input shaft o-ring or the converter itself, there is a high probability of fixing this without pulling the trans again.
Do you recall replacing and installing that o-ring?

I think most people on this forum would be happy with or even prefer an On/Off TCC and not PWM.
Does Fitzall make an oversize TCC On/Off valve?

 

Thanks for all the assistance.

I've dropped the valve body, but I can't get the sonnax sleeve sleeve out of the tcc regulator valve bore. Does this picture look correct?

Still working through the checks on the tcc apply valve in the pump.

 

This spring moves freely , should it?

 

Here's how it's assembled in the valve body. There's a significant gap between the spring. I'm not sure if that's normal.

 

From looking at the photo provided, The automatic transmission torque converter clutch isolator/ regulator valvetrain looks 100.00% correct.

As just mentioned above by "MaroonMonsterLS1", the automatic transmission control valve body assembly should be wet vacuum tested.

Perform this test directly over the passages that are over the automatic transmission torque converter clutch isolator/ regulator valvetrain.

Also look to see if the new isolator valve, regulator valve, or regulator sleeve has been gouged, since you had a difficult time removing the new valvetrain from the bore.

If there is no vacuum leak found, and no gouge (would prevent valves from moving properly) found, let us know and we will proceed forwards to other potential root causes.

 

Thanks everyone.

I pulled the tcc apply valve from the pump and it's definitely correct.

I just need to make up a proper vacuum tester with some acrylic which should tell me if I did the ream job properly.

Assuming the vacuum test is ok, I guess I'll be dropping the trans again to check the o ring on the Input shaft ( even though I know it's on there), and to vacuum test the tcc circuit on the pump.

In kind of running out of idea =(

 

If it were me, I'd swap the valve body before pulling the trans; of course I do have spare VBs kicking around. Oh, and did you swap the TCC On/Off solenoid yet?
Without reading the entire thread again, are you sure your converter has working lockup?

 

Agreed, unfortunately i don't have any spare VBs laying around, and i'd rather test my current one before forking out for a new one.

I've purchased a cheap chinese vacuum pump and am in the process of making up a sonnax cloan vacuum tester. That will proove weather theres a leak on the valve body in the TCC circuit somewhere. I'm hoping that I did a bad ream job and can sort this without dropping the trans.

the Torque converter is a re-manned one from a local reputable shop, so I'm trusting thats correct, unless it was DOA.

I tested both TCC and PWM solenoids and they have the correct resistance reading, and they also have a noticable 'click' when applying power to them. So i'm confident its not a solenoid problem.

If the valve body passes vacuum test, i'll pull the trans and vacuum test the TCC circuit in the pump, as well as check the o-ring.

Anything else I should be checking ?

 

In terms of a leak in one or more of the automatic transmission torque converter clutch circuits...
Usually leaks will be found at:

-TCC regulator valvetrain.
-Automatic transmission control valve body to case gaskets/ separator plate (valve body/ or case may not have a flat enough surface to seal or may be damaged),
Also using an incorrect year or model separator plate and/ or gaskets can cause an interrupt in the circuits.
-TCC apply valvetrain.
-Automatic transmission pump assembly to case gasket (pump assembly or case may not have a flat enough surface to seal or may be damaged).
-Automatic transmission pump assembly (pump halves may not have a flat enough surface to seal or may be damaged).
-Automatic transmission pump assembly front seal.
-Automatic transmission pump assembly stator support front bushing (if badly worn, will create a leak between apply and release circuits).
-Automatic transmission turbine shaft (input shaft) assembly/ O-ring/ encapsulated check ball.
-Torque convertor assembly.

I may have missed something as i am exhausted, however that should be the bulk of it.

 

Cool thanks, thats exactly the detail i wanted. Ill work through each item on the list once my vacuum tester arrives.

Looking through the list, specifically at this item:
-Automatic transmission control valve body to case gaskets/ separator plate (valve body/ or case may not have a flat enough surface to seal or may be damaged),
I used a transgo seperator plate, with new stock gaskets. Was I supposed to change any of the holes in the new plate? I understand there are two types of valve body gaskets, the ones labled 'V' and 'C', and the ones labled 'VB' and 'CA'. - The transgo site doesnt say which of the two sets of gaskets to use. Could that be where i went wrong?

 

Yes that is definitely possible that the wrong gaskets were used...

I do not know off the top of my head which would be correct in your situation...

Please call them and inquire.

 

When using the TransGo separator plate, they use the late gaskets. The late gaskets from them do not have the white stripe on them, however they are the same, just no white stripe on them. C or CA = case side. V or VB = valve body side.

 

Hmm ok.

According to the atsg the earlier style gaskets have c and v labels to identify the case side and valve body side, and the later models have ca and vb on them. My understanding is that is how they identify the early versus late style gaskets.

Because the transgo separator plate documentation doesn't say which to use, I went with the atsg recommendation which is to use the c and v labeled gaskets based on my transmission year.

is there any documentation anywhere which clarifies the correct gasket to use for the transgo plate? I'm hoping that this is the cause of my issue.

 

PBA is your documentation.
If he says that transgo plate uses the late gaskets...then use the late gaskets.

Also...vortechiroc it was a nice gesture to make a list...but sonnax has a free vacuum test guide for the 60e posted on their website. It highlights every passage/valve that is critical to check.

 

While this most likely isn't the cause of your TTC problem, yes you are to change the hole sizes on the TransGo plate as per the instructions. This is a generic plate that fits many applications and hole sizes need to be tailored to fit your application.

As for valve body gaskets I like to match them to the old gaskets to make sure none of the holes are blocked off.

 

How do you identify early from late gaskets? Part No., I suppose...would anyone have that?
Mine's a '95 4l60e...and it was a GM Reman (looked fine, tho).
Thanks for any help. Jake

 

Late has a white stripe and VB, CA.
Early has no stripe and V, C.