Is it normal? The transmission is in a 2008 silverado and it keeps breaking drums it is around 500 HP build is there a alternative drum?

 

4l70E Sorry

 

Where are they breaking?

Chris

 

Where the snap ring goes, blows the aluminum off the end of the drum.

 

alot of the time shift shock will cause things like that or cracks in the drum

 

Take a look at wot line pressure, clutch clearance, feed hole size and also the tune. If this trans has a shift kit and a tune, make sure that the line pressure settings are at the factory settings. These are all things that can effect the life of that drum. Good luck. Vince

 

After talking to the tuner I think I have a issue third time this trans has had drum issues, doubt its drums but the tuner has the TC locking up in 2nd. Do any of yall lock up under 50 M.P.H. or under 4th?

 

Having the converter locked when the trans shifts can be very hard on a transmissions internals. I'm sure it's not helping. I would correct this and also look at the other things I have mentioned. Vince

 

I don't see why locking in second would blow out a snap ring. But it is harder on the input shaft when you shift locked up. I think it would break the shaft or split the drum.

Chris

 

Breaking the snap ring out of the end of the drum has in my experince one of two likley causes and neither would be related to lockup in any gear though it is a bad idea to lock the converter during a shift or in the lower gears imo.
But the reasons for the syptom you have i have noted are
EXCESSIVE 3-4 CLUTCH CLEARANCE
EXCESSIVE MAX LINE PRESURE (Note max line is not set in tuning but rather mechanically for instance on our dyno many times when using for instance the sonnax or transgo boost valve we have to lower the max line as its excessive)

Hope this helps when you first mentioned breaking drums i assumed shaft or drum center this is not a power related failure more than likley a build or setup failure thats being repeated.

 

It was the boost valve.