Low gear in high range

Way I see it, if it were ok to use, Eaton would have included it in the shift pattern.

 

That information was not accurate.
The low gear spins the same speed in high range as it does in low range in relation to engine RPM.
The high range gear ratio is what makes the truck go faster.
Think of a ten speed.
In sixth gear your right back in low gear again only in high range.

 

There was a thing known as a Performance 9 speed that used that gear. It was set up with the 8th 9th gap as a split, so the over and back position was only used in 9th. 5th was the ghost hole to keep the steps even across 4-5-6. Which also indicates its not likely a structural issue.

I think the reason it's not used in most 9/13/18 is that the steps are better without reusing the LO ratio.

 

It's almost a redundant ratio is one reason its not a normal gear or rather part of the shift patern.

Like I said I use it a lot turning corners. 5th gear is just a touch to fast. And rather than dropping to 4th in the low side I just use low on the high side.

It's an odd ratio. I rarely split gears on my 18 speed but when I use that gear, low on the high side and high split I have to split down before going into 5th or its to much of a rpm drop. If I'm going from 4th high I normally go right to 5th high. If that makes sense. On an 18 I would normally count every gear. 5th high should be 12th gear in my book.

 

Or would have locked it out if you weren’t supposed to use it.

 

Back in the day, 13 speeds didn't have any interlocks on the splitter. You weren't supposed to split low range, but you could. Nowadays there's the mechanical interlock on the shift knob and an interlock in the air system that won't let the splitter work until the high range shift is complete. Those additions were likely driven by the demand for greater warranty coverage.

 

You can still get around that interlock on the shift knob though and shift a 13 like an 18. Definitely do not advise doing that though since its not meant to do it.

 

I'm pretty sure the newer 13's don't send any air to the splitter until the actual range shift. If I'm in a low range gear and hit the range and then the splitter (to fool the shift knob interlock) , it won't split like older models would. There's 4 lines on these newer shifters, 2 supplies and 2 signals.

 

You must be a “company man”……..

 

Thanks for the input, but I’ll take my drivetrain gurus advise.