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Joe
Joe, ASE Certified Technician
Category: Chevy
Satisfied Customers: 7136
Experience:  ASE, electronics, Marine inboards and electronics, automotive drivability, all around repair tech,
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I have an LQ4, with 230 comp cams, 8.1 injectors, headers,

Customer Question

i have an LQ4, with 230 comp cams, 8.1 injectors, headers
JA: Thanks. Can you give me any more details about your issue?
Customer: 4l80e trans, is banging into OD at 40-45 mph all of a sudden, sorry i hit send to soon
JA: OK got it. Last thing — Chevy Mechanics generally expect a deposit of about $18 to help with your type of question (you only pay if satisfied). Now I'm going to take you to a page to place a secure deposit with JustAnswer. Don't worry, this chat is saved. After that, we will finish helping you.
Submitted: 8 months ago.
Category: Chevy
Expert:  K. Wiggins replied 8 months ago.

Hello, are you running an aftermarket transmission controller or stock PCM

Customer: replied 8 months ago.
No transmission controller
Stock pcm
Expert:  Joe replied 8 months ago.

Hello,

Thank you for allowing me to assist you, my name is ***** ***** I will be happy to assist you with your concern today.

So the problem only occurs in o/d and only at 40-45mph?

Are you running a programmer and or have any tunes written?

Factory or aftermarket converter?

Thanks,

Joe

Customer: replied 8 months ago.
No programmer and yes it has been tuned HP tuned
Yes only at 40-45
Other then that it shifts smooth
Also I forgot it has a 3000 stall convertor
Expert:  Joe replied 8 months ago.

Ok so it has a custom tune written which I suspected with the work that has been done. Where any shift or trans adjustments made in the tune?

Did this only happen after the engine was built with these parts and installing the 3000 stall or did everything work correctly with these changes but has now became a problem?

Thanks,

Joe

Expert:  Joe replied 8 months ago.

I am checking because a couple of things that come to mind are first to connect a scan tool and watch the TPS in that range to be sure it is not having a problem in that range and is correct readings throughout it's range and next is the torque converter itself, thus why I was wondering if it has been this way since installing the stall converter or if it worked with that stall convert up until now. Has the transmission had any modifications done other than a stall?

Thank you!
- Joe

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