Ive got a 2003 5.4 Auto with the Shift in the fly 4X4 system and whenever I shift from 4H to 4L, It seems to have some problems. Going from 2 to 4H is fine, but whenever I go into 4L, I get a loud grinding noise that lasts for about 10 seconds. After the noise stops, both the 4x4 and 4Low lights flash on and off a few times, then it engages and is fine. Also, when the grinding is going on, my speedo is slowly climbing as if i'm moving. It goes up to about 15 -20mph before it comes back down. Any ideas on what might be wrong here? I'd really appreciate any advice.
Thanks!

 

No body has any ideas on this?

 

Transmission in neutral? Vehicle stopped? Foot on the brakes? Any answer that is a no may cause grinding. If all three yes there could be problems with the GEM, shift motor if electric shift, relays or transfer case.

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Thank you for your input, All three questions are a yes. Oh and also, when my truck was at the dealership, they said my tranny was on its way out. Do you think because of that, there could be an issue?

 

With the transmission in neutral the output shaft can not turn the t-case input shaft. The vehicle is stopped it to insure that the T case output shaft is not being turned by the wheels. Foot on the brakes sends a signal to the GEM to allow the shift. While a defective transmission could cause the t-case input shaft to turn I would suspect the shift motor or a shift fork in the t-case.

Regards

Jean Marc Chartier

 

Sweet, thanks a lot for the info Jean.