MyslowGTO

Ok I'm helping my brother install new forged ls2 in his 05 GTO that is the awesome part. We are having a problem with a RPM trans and a Circle D converter. I installed the converter just like I have done on other builds. Well when I try to turn the converter it will turn then stop. You can turn it back then forward again and it will turn then make a light pop sound. Of course I was like s**t that wasn't suppose to happen. Tried it once again think it was just popping in place same thing. The converter just came back from being worked. The engine builder said that is not normal. The trans was working fine before the engine cracked a piston. Of course everybody is closed for the 4th so we need some help from you guys. Any ideas would be great.

MyslowGTO

Ok... after messing with it for a hour I try it again just now and it spins freely now. Thank you baby Jesus. I spoke with another trans guy also and he said it could have been that the trans had been setting for a few months (waiting on the engine build) that something in the trans was a little stuck. Well thanks just glad it fixed itself.

ABA383

iTrader: (1)

I hope it all works out for you. The new owner of my Formula hurt my 4L60E (had a "stall wall" issue when he raced it with a vig 4000..he fixed the tune but he hurt the trans) and went with an RPM level 5 and it lasted 10-15 runs before it broke. It was installed by a very reputable shop that I've used for years. Their customer support was insulting, blaming everyone but them. I've used and continue to use a local builder, but the new owner had read online about how good the RPM trans was. $2500 in the trash. I'd contact them now because if it fails they are probably going to try to blame you due to your above posts. Good luck with everything.

--Alan

MyslowGTO

Just to let you guys know what happen the pop sound was the pump its broke. Not sure how it happen as of right now the trans isn't 6-7 months old. After speaking with RPM we are going to have our trans guy do the repairs.

I also think we are going to do a 4l80 swap soon this trans isn't going to hold the HP level the car is at. The car is should put down some where in between 900-1000 hp. Sucks we are only going to have it tuned for around 700 to try and make the trans last as long as we can for now.

ABA383

iTrader: (1)

We believe that the pump went up in ours too. RPM says that their trans was bullet proof and indestructible...and it had to be our fault at install. I didn't recommend them to begin with and definitely won't now. And my old Formula only makes 375 rwhp...

--Alan

MyslowGTO

For the price they should be... but guess they aren't that strong. Our local trans guy is saying this isn't the first one he has seen break like this. They won't get any of our money again. The price we got from our trans guy on a 4l80 to hold the hp level we want is the best bang for the buck for sure.

RevGTO

iTrader: (12)

Broken pump comes from the converter being not fully seated on the input shaft. This problem comes up frequently on this forum and it has nothing to do with the quality of the tranny build.

Jake's Performance

iTrader: (2)

Bravo!, some common sense...

MyslowGTO

I would agree with that any other time, but the when the trans guy looked at it he said it was from the hp level. The trans was taken out with the engine blew and I found the problem before it was installed. It was not from the converter not being installed the right way. But either was it is fixed now and getting tuned this week!!! I'm not a first timer.

Jake's Performance

iTrader: (2)

How does HP break a pump?

Simply put, it doesn't.

The pump never sees HP, HP goes through the input shaft, some effect on the stator shaft, but the pump gear/rotor only sees the HP required to drive it against the pressure it creates.
It sees RPM, it sees pressure, it sees hopefully lube, but anybody that believes HP breaks pumps is mistaken.

A pump breaks because it is assembled wrong (usually nearly immediately fails), converter installation (BY FAR the most common cause), contamination (2nd most common cause), cavitation (common failure mode on industrial hydraulic pumps), pressure spike from a regulator issue, or possibly a faulty part.

In the case of your unit, if it made it several thousand miles, it wasn't an assembly issue, or any issue with the initial install, but more likely an issue with the removal of the trans, or re-installation the 2nd time around.

I've been building transmissions for some time now and I've seen just about every failure that can happen. I've seen MANY converter installations gone wrong, and in almost every case, it's NEVER the installers fault according to them.
I've seen professional shops break pumps, I've seen experienced installers do it, I've seen novices do it and in only a few cases have I ever had someone admit they did it.

Now the other side of the story. A 4L60E uses a vane style pump. It's not as strong as a gear or gerotor style pump. The cuts in the rotor for the vanes make it weaker and I have seen them break from pressure spikes or cavitation. 13 vane rotors seem to be more likely to do so.
That is why they make billet rotors for them.

It's possible the pump was already injured and the noise you heard was a broken rotor.

MyslowGTO

It is possible the trans guy damaged the pump when he had it. People will cover their own a** most of the time. I know I installed the converter correctly. I will be honest I know my stuff when it comes to engines but auto trans I am a dumba** and I just take the advise of the trans guy. I have always had t56 cars. I can tell you RPM customer service dept. sucks IMO.