48RE Converter Locked After Rebuild

Tobin

Tobin

5.7 IDI Powaa!
Beating my brain on this one, pretty sure it is VB related but want to make sure.

Customer destroys the input shaft (stock) on a aftermarket transmission. I think the converter had issues. Everything else in the transmission looked pretty good.

Rebuilt the transmission (48RE), cleaned, new billet input, new (used OEM) front cover and pump. Valve body sent out to be cleaned and new electronics, converter rebuilt, clearances measured and set. All soft parts replaced. New clutches, bands, etc.

Put it in the truck, reverse works great, put it in drive and it instantly kills the engine.

My thought is something with lockup circuit in the VB. Pulled solenoids and the screen looks clean.

What am I missing?

Thanks for the help.
 
Tobin said:
Beating my brain on this one, pretty sure it is VB related but want to make sure.



Customer destroys the input shaft (stock) on a aftermarket transmission. I think the converter had issues. Everything else in the transmission looked pretty good.



Rebuilt the transmission (48RE), cleaned, new billet input, new (used OEM) front cover and pump. Valve body sent out to be cleaned and new electronics, converter rebuilt, clearances measured and set. All soft parts replaced. New clutches, bands, etc.



Put it in the truck, reverse works great, put it in drive and it instantly kills the engine.



My thought is something with lockup circuit in the VB. Pulled solenoids and the screen looks clean.



What am I missing?



Thanks for the help.
Click to expand...
Put a pressure gauge on it. If it's locking the TCC the pressure will max out in the forward gears. I don't think it's an internal TC failure because it's working in reverse? (Be warned I'm not a trans guy)

For example, mine jumps from 150 psi to 200 once the TCC is applied

Sent from my motorola one 5G using Tapatalk
 
biggy238 said:
Put a pressure gauge on it. If it's locking the TCC the pressure will max out in the forward gears. I don't think it's an internal TC failure because it's working in reverse? (Be warned I'm not a trans guy)

For example, mine jumps from 150 psi to 200 once the TCC is applied

Sent from my motorola one 5G using Tapatalk
Click to expand...

I should have check the pressure but I already shipped the VB out. Now I wait to see what they say.
 
FYI for anyone that experiences the same problem, valve body had internal cross leakage. Re-installed VB and works as it should.
 
1320Cummins said:
Sounds like someone installed a valve backwards...
Click to expand...

I'll have to study the valves to understand them a little more.

I will require all valve bodies sent out to be bench tested now.

Would like to build a test stand now and start figuring out the VB magic.
 
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