zbo2

have a 4l60e in a 05 astro..... had it rebuilt by a friend after the 3-4 clutch pack went. i had him get a rebuilt converter just because of the mileage 200,000+. worked great for 2 months then the pump impeller shattered. he went through the trans to make sure everything was ok and put a rebuilt pump in it and i was back on the road....again everything was perfect for about 2 months and the same thing happened again. so now i'm wondering what would make the impeller break like that.....i'm suspecting the converter since that was the only "hard" part that was changed but don't know if something in the converter could cause that. the guy that rebuilt it is pulling his hair out as well as me........... i don't want to "guess" as to what the problem is, i'd like to be sure so i don't have to go through this again. any ideas?
thanks
Joe

mrvedit

I don't think anyone here can "be sure" as we don't have the parts in hand to inspect and measure. So, I'll just share ideas of what I would do...
BTW, I assume by "pump impeller" your mean what GM calls the "pump rotor".

First, I would check if either "pump ring" broke - early year ones were susceptible to break and ruin the entire pump. I suspect this is not the case.

Second, I suspect you are right about the converter being the problem. I suspect the converter is wobbling; the pump has clearance for a bit of wobble, but not a lot. If either the mounting pads on the converter or the holes in the flexplate are out of position, it would wobble.
While a bit involved, you might be able to check this with the trans removed by mounting the converter to the flexplate and either starting the engine or at least spinning it with the starter to visually see if the converter is "true". (I have never needed to try this, so I admit I am guessing here.)

Perhaps someone else has better ideas...

zbo2

just to get things straight........ this is the 3rd pump. the original broke then the 1st rebuilt one. the rebuilder supplied a second rebuilt one for free and now that one has broke........ the original pump and converter worked fine, just the clutch pack went south so i'm pretty sure the flex plate is ok.... i will double check the mounting pads on the converter although i usually do take the paint from the rebuilder off before i install it. other than the wobble you mentioned i'm not sure what could be making this happen and the only thing different is the aforementioned converter.

mrvedit

I only mentioned the flexplate to cover all bases. With a prefect converter, even over-sized holes in the flexplate shouldn't matter.

Perhaps one of the converter experts will chime in soon...

Circle-D

iTrader: (21)

Are you checking the distance between the flexplate and converter? It might be to much and you are pulling out of the trans to much....

Chris

zbo2

I will check that chris..... pretty sure it was less than a 1/4 inch closer to an 1/8.... how much is to much?
thanks

mrvedit

Chris should confirm this, but my understanding is that 1/16" to 3/16" is the target distance. I'm guessing that somewhere around 5/16" will start to pull out.

zbo2

thanks........ have to get a moment to get the starter out and the bolts out to see...... but i'm pretty sure i'm right in those numbers.