6-speed question

[TheBac]

Mechanics at work are stumped. 6 spd Alli 1000, same as in the 06-up pickups, will once in a while show the "range shift inhibited" light and no matter what gear you select, it will not shift. If you restart the truck a couple times, everything will go back to normal. No codes are set. Truck does not have manual mode.

Any ideas?

 

[emerson]

Nsbu?

 

[TheBac]

Nsbu?

Do the internal ones for the 6-speeds screw up too?

I was thinking it was a solenoid, but I'm no tranny expert.

Figured I'd ask here, since problems such as this are old hat for Mike....I figured he'd know what was wrong with it.

 

[McRat]

I would check any grounds and connectors for corrosion if it's intermittent and runs good when it's not freaking out.

 

[TheBac]

Thats the thing...you can shift into any gear, whether drive, 1st, or reverse, etc...and nothing happens. The light pops on. Shut truck off for a bit, restart, and the light is gone and it shifts normally.

Allison tech that works with our mechanics told them that next time the light pops on, to have driver leave truck running rest of day, and he'd meet driver and scan truck for codes. At Christmastime?!? I doubt any driver would give up any time for an on-road diagnosis.

BTW, the 6.7/Alli combo in my truck is flat out badass, except for the Alli having learned that I'm a lead-foot. LOL That 6.7 is a quiet, powerful motor. Alli could use a transgo Jr kit or whatever is used to firm up the shifts.

 

[Mike L.]

Got to have a code to help out. The internal mode switch ( NSBU ) is known for going bad.

 

[offtohavasu]

Don't know if it's true or not, but heard some buzz about bad TCMs as well.

 

[jpowel29]

My 6spd Allison would throw the Range Shift Inhibited message and not go into gear. At the time my trans was slipping while under full throttle and had likely suffered tie-up. I did get error codes however.