BANG then slippage in nag1 transmission.

stangtmb

New member
Hi, I greatly appreciate anyone's input or help on this. Working on a 2006 long and tall.

At 100,600 miles there were zero issues with the transmission except for a slight RSN. I performed a transmission service: Drained torque converter and pan, performed Doktor A's RSN fix with a #55 drill bit, replaced the trans filter, then filled with Shell ATF 134. Brought up to operating temp and verified correct level with dipstick at the 80ºC range. After this, the transmission performs beautifully.

At 101,800 miles I hear a very loud bang from the transmission and it immediately starts slipping. Still drive-able but it has to rev a lot higher than normal to get going and stays in high rpm. Arrived home and shut it down. Moments later I started it up and it acts like nothing ever happened. Over the next few days I experience intermittent slippage. Not as bad as the first time but definitely noticeable. I checked the trans fluid: it is clean, smells good, and the level is perfect. Plugged in my generic scanner and there are no codes. Now I am at a loss. I plan on driving it on a little road trip this coming weekend and would really like to get it back to normal before. Not sure if it is relevant, but the GDE tune is installed.
 

stangtmb

New member
I would speculate something with the converter clutch as well. But why would it be intermittent and what is the suspect for the loud bang?
Is there any record of this ever happening due to the RSN mod?
 

Axiom

Mike from Florida Van Man
Sounds like what I just had happen to me. My EGS module had a code for RPM Sensor 3 faulty. The TCM under the driver’s seat was dry.

Drop the pan and clean the rpm speed sensors. Verify the 13 pin connector is clean and has no contamination. I put a new conductor plate on personally but had found metallic goop on the sensors. If you don’t drive it too much like that it may still be salvageable? Best of luck!

I drove mine for a week clearing codes to get it to start shifting again. By the time I had done the fix, it was still “slipping” in every gear but after driving it 100 miles today and manually shifting it sooner, the computer is shifting the engine sooner with significantly less flare.
 

stangtmb

New member
Turns out that my situation also had a code for RPM sensor 3 faulty. Just like Axiom, I found goop on the sensor but replaced the conductor plate anyway. Put in a new filter and electrical connector socket, filled up with new fluid and its been running great for a couple thousand miles now. Thanks for the advice!
 

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