cracked converter hub? 2x?

[JDSfastGN]

Alright, just looking to see what others thought. Some think its pump harmonics and some think its just the converters but the converter hubs cracking is pretty common from what I understand. I have a PTC 9.5 that I love. About 2 months ago I installed a 10 vane pump that put out great pressures (275) and worked great. Soon after I installed it, on its first long trip i got a smoke show behind me. I assumed it was the front seal, but it turned out to be a cracked neck. It was intermittent and would come and go depending on TV pressure and rpm. I talked to Dusty and since the shootout in Noble OK was less than 2 weeks away, I took it to a well known local converter shop that installed a new neck. While putting the pieces to this puzzle together I figured it must have been caused by the 7 vane pump that I had just taken out, because it whined and buzzed when it got hot. I just figured I hadn't driven it with that pump in a while(the whine annoyed me to no end) so it never got hot enough to open the crack and let it spew fluid everywhere. So I installed the converter with the new chromoly neck and took it to Noble with no issues. Now after I took it on a 3 hour trip its doing the same thing. Every once in a while I get a large amount of fluid that spews out and I'm assuming its the same damn issue. So now with a new neck, I have to assume it was my new 10 vane pump that caused the the neck to crack, and here goes another 500$ into this damn thing for another fluke problem haha. Has anybody seen this and found what the issue was? :redface: I'm positive its not the converters fault so nobody think bad of PTC.

 

[challengermike]

Make sure you have the 2 dowel pins in the engine block,also make sure the pilot hole in the crank fit the converter nice.And when you install the trans that it has some play before you draw the converter up to the flywheel.Im pretty sure a cracked neck is a alignment issue.

 

[bison]

Make sure you have the 2 dowel pins in the engine block,also make sure the pilot hole in the crank fit the converter nice.And when you install the trans that it has some play before you draw the converter up to the flywheel.Im pretty sure a cracked neck is a alignment issue.

+1. Id replace the entire pump assembly too.

 

[JDSfastGN]

Both dowel pins are present and the snout measured out perfect. The Flywheel isn't cracked and the engine has only had a line hone, not a line bore so alignment with the crank should not be an issue. There was almost 0 runout on both the flywheel and converter. I would imagine the pump rotor would crack before a chromoly hub would if it was some kind of misalignment. This kinda stuff would only happen to my personal car haha. I have close to 30 200-4rs under my belt for local guys lol and have never come across this problem using 7-10 or 13 vane pumps or any brand converter

 

[Alky V6]

Have you checked for any line pressure spiking under different driving conditions?
Were the slots in the hubs properly radiused?

 

[JDSfastGN]

I have only been a few miles with a gauge attached and all was normal. I've smoothed out the tangs on the converter neck on mine because it was a tight fit but I wouldn't call it a radius or anything. Never done it on any other converters

 

[Alky V6]

At the base of the hub slots, it was determined a long, long time ago (20-30 yrs.) that a generous radius corner resisted hub cracking better. If the slot has a sharp angle (90 degree cut) at the base, I'll bet that's where the crack started. Right?

 

[JDSfastGN]

At the base of the hub slots, it was determined a long, long time ago (20-30 yrs.) that a generous radius corner resisted hub cracking better. If the slot has a sharp angle (90 degree cut) at the base, I'll bet that's where the crack started. Right?

Good to know, yes the first time that is where it cracked. I dont have the current one out (in fact I have a 150 mile drive ahead of me). I will be replacing the pump and i will radius the new hub after its installed. So what other theories are out there as to why this happens?

 

[Dusty Bradford]

At the base of the hub slots, it was determined a long, long time ago (20-30 yrs.) that a generous radius corner resisted hub cracking better. If the slot has a sharp angle (90 degree cut) at the base, I'll bet that's where the crack started. Right?

The real interesting question for me is why are the 200r's more likely to crack here than other trannies? All of them are slotted the same way, yet the 200r's are more likely to do so.

 

[Alky V6]

The real interesting question for me is why are the 200r's more likely to crack here than other trannies? All of them are slotted the same way, yet the 200r's are more likely to do so.

I believe the wall thickness of the hub is thinner than say for a 400. I know the OD is smaller. Add to that the high line pressures that the 2004Rs are forced to use to keep things from slipping. A 400, you can get away with 190 max psi line pressure. A serious 2004R is going to be closer to 300 psi, with a weaker hub to drive that pump.

 

[Dusty Bradford]

I believe the wall thickness of the hub is thinner than say for a 400. I know the OD is smaller. Add to that the high line pressures that the 2004Rs are forced to use to keep things from slipping. A 400, you can get away with 190 max psi line pressure. A serious 2004R is going to be closer to 300 psi, with a weaker hub to drive that pump.

Thanks.

 

[Chuck Leeper]

"i will radius the new hub after its installed."
Maybe, add a small "mouse bite" in each corner of the slot, B4 U install? Keeps the shavings out of the pump, and could be machined in a mill for a better finish??

 

[quickt]

Crazy the hub cracks. You can break one of those Rotors very easy.

 

[JDSfastGN]

Thanks for the replies guys. I made it back to town with no issues... its very off and on. I backed way down on the Tv to try and lessen the line pressure for the drive. Hopefully I'll have it out soon and I can look for any issues. Chuck thanks for the idea about the "mouse bite" Ill let ya know what I decide to do. Anything to relieve stress on the slots.

 

[Alky V6]

I agree with Chuck. Modify the hub BEFORE it is fitted to the T/C. It will be much easier to work with and you don't have to worry about getting metal in your T/C. Plus, if you screw up or have a change of ideas of how to do the radius, you can easily get another hub.

 

[turbobitt]

The real interesting question for me is why are the 200r's more likely to crack here than other trannies? All of them are slotted the same way, yet the 200r's are more likely to do so.

Another thing to consider is that there is not just a torque load on the drive hub but also a hoop stress from the pressure. Plus if the line pressure is not constant than it adds to the fatigue failure.

 

[mikestertwo]

Make sure your pump halves are aligned properly.

 

[JDSfastGN]

just wanted to update. The converter checked out ok and does not have a crack this time... now im a bit lost. I will be replacing the pump but honestly don't see anything wrong with it either.

 

[challengermike]

I would have the converter pressure checked,they can leak from the welds.It also helps some times when you check them to throw it in the hot tank for alittle bit to heat it up.i have seen a few not leak cold but leak when there hot.Was there a spray trail around the bell housing from the converter throwing the fluid around?Also look at the front of the converter and see if the fluid trail starts there going around the front of the converter and towards the edge.It will usually leave a trail you can see.That would tell you if its coming from the front of the converter or the pump seal.If you dont see that and you do see it sprayed all over the bell housing i would assume it would be out of the weld in the middle or i have seen them leak from under the mount pads.

 

[JDSfastGN]

it was air checked at a converter shop, but we didn't heat it up
I'm gonna heat it up myself and air test it though