Hi everyone,

I’m currently rebuilding a 2006 4l60e. I have a few parts from another transmission but I do have a 300mm input shaft with reluctor, with a matched iss style stator.

I was performing some air checks before reassembly and I seem to have a significant cross leak between the 3-4 clutch circuit and forward clutch circuit when the input drum is in the pump. The input drum itself is air tight, but I think this leak is between the Teflon rings on the input shaft. I think this is the case based on the drum its clutch itself seems fine and on all the GM diagrams, the 3-4 and forward clutch circuit do not have a much of a chance to cross leak inside the pump (being the forward circuit is straight drilled through the body into the bore).

I found other thread similar to this when people use scarf-cut seals, but I used the normal resizing type. I even replaced the input shaft seal again between 3-4 and forward clutch with an official GM seal, but still leaks.

My question is, do these seals expand more once they warm up? Do I need to worry about this?

There was something else that I noticed. It seems to leak more from the 3–4 clutch into the forward clutch circuit, compared to when air is applied to the forward clutch (with overdrive plugged), it seems less severe. I did think that the forward clutch will be applied in the 3-4 circuit, so at least the leak is worse than that direction, however, I’m still very worried about my 3-4 accidentally applying and burning up the clutches.

I attached a video showing the air leaks!

https://youtu.be/xhBpOTBUNAo?si=Hzk-tjZg8c2Hmxsd

Let me know if you guys have any input, and if I’m just overthinking this!

Thank you!

 

This may help

 

Those seals generally seal pretty good , I would check of course inside of stator for wear and for leaks between stator and pump body and with pump disassembled look at surfaces particularly in the areas to do with forward and 3-4 see if you have any dull looking areas (erosion leaks) Last if for any reason you swapped either pump half they must be machined. I have seen this on the lathe over and over , The pumphalve warp over time together, As long as they stay matched you are probably ok but when swapped it will leak like hell between halves .

 

Thanks for the advice! I ended up getting a GM stator/pump cover on closeout from RockAuto for really cheap.

Then after struggling to find a pump body online, I got a really nice machined pump body shipped from Jim at Built Right Transmission in Louisiana. He was very reasonable priced and the machining looks great.

Nonetheless thank you for the advice to prevent my 3-4 dragging and burning up from a crossleak!