12 Speed With Deep Reduction Switch On Dash

[rich]

when i try to use the air switch for low low i can hear the air piston move but nothing happens . I took the piston off to top of the tranny and i could not engage it by hand. it moves back and forth a little I know there is a lock out when low low is being used. I think maybe a bent or broke shifting fork is the culprit. Any body have any experiance with this problem and can i change the fork with out breaking the tranny down. I have good access with tranny in the the truck (superliner) Thanks, Buddy

[Lmackattack]

Its been 10 years last time I worked on one but I think you can pull the shift cover off to access all the parts that shift the transmission. If the air cyl was clean and operates as it should the next thing to look for is a bent fork.

[fjh]

Its been 10 years last time I worked on one but I think you can pull the shift cover off to access all the parts that shift the transmission. If the air cyl was clean and operates as it should the next thing to look for is a bent fork.

I've Seen this happen before!

Where is the cyl located front or second lid back?If it is located in the front lid you can disable the lock out by cutting off the lock out portion of the shift rail !This can be done in the truck.we Need to idenfiy shift lid configuration!!! If the air shift is mounted on the front remove that lid and try to move the fork manually if it moves ok,cut the lock out grooves off of the frist speed shift rail that is sticking thru into the foward case with a zip disc Or grind a bit off the top part of the lock out groove and re assemble. There is also one other Possible fix Buy the proper gasket for that lid that may raise it up enough to clear the lock out groove!

[rich]

I've Seen this happen before!

Where is the cyl located front or second lid back?If it is located in the front lid you can disable the lock out by cutting off the lock out portion of the shift rail !This can be done in the truck.we Need to idenfiy shift lid configuration!!! If the air shift is mounted on the front remove that lid and try to move the fork manually if it moves ok,cut the lock out grooves off of the frist speed shift rail that is sticking thru into the foward case with a zip disc Or grind a bit off the top part of the lock out groove and re assemble. There is also one other Possible fix Buy the proper gasket for that lid that may raise it up enough to clear the lock out groove!

the air cylinder is up front and on drivers side directly next to main shifter i checked and cleaned the cylinder and it works fine tried to move the fork on the shif rail but it only moves i little about 1 inch back and forth and is more forward then back. I am wondering if i can take the shift fork out by sliding the rail back after i take the lock bolt out?

[fjh]

the air cylinder is up front and on drivers side directly next to main shifter i checked and cleaned the cylinder and it works fine tried to move the fork on the shif rail but it only moves i little about 1 inch back and forth and is more forward then back. I am wondering if i can take the shift fork out by sliding the rail back after i take the lock bolt out?

if your inch is the same as mine ? 1 inch is almost the stroke of the forks total movment.

You might be able to remove the fork By pushing the rail into the clutch housing! MAYBE!I beleive the lock out is your problem thou no need to remove it!

Tri making a thick gasket from a cerial box and installing it under the lid of the center section where the stick goes thru! 20 thou may let it work again!Also check to make sure when you remove the front cover of the trans that there is NO spring under it! The detent spring is ment for stick shift apllications it shouldn't be there in your app!That somtimes will cause the air style to stick! The shift lock out sticks thru into the next section of the box so you need to remove that lid to access the lock out .But if you pull the lock bolt on the shift fork you will likly be able to slide the shift rail into the belhousing enough fo grind off the lock out ridge on the compound rail!

[rich]

if your inch is the same as mine ? 1 inch is almost the stroke of the forks total movment.

You might be able to remove the fork By pushing the rail into the clutch housing! MAYBE!I beleive the lock out is your problem thou no need to remove it!

Tri making a thick gasket from a cerial box and installing it under the lid of the center section where the stick goes thru! 20 thou may let it work again!Also check to make sure when you remove the front cover of the trans that there is NO spring under it! The detent spring is ment for stick shift apllications it shouldn't be there in your app!That somtimes will cause the air style to stick! The shift lock out sticks thru into the next section of the box so you need to remove that lid to access the lock out .But if you pull the lock bolt on the shift fork you will likly be able to slide the shift rail into the belhousing enough fo grind off the lock out ridge on the compound rail!

thanks for the info, i will be working on it this morning (monday) Buddy

[rich]

thanks for the info, i will be working on it this morning (monday) Buddy

I took the top of thr=e tranny off and found that the lock out that is applied to the cover with a spring and detent ball was broken in half. it is a rectangle box type mechamism thar the shifter tip goes through. looks like it was desinged so when you use deep reduction the only gear that can be used is 1st gear. so i popped it out and now i have deep reduction. Hmmm wonder where the broken piece is Yuk Yuk going to see if i can find one somewhere, man it is a flimsy piece made out of some kind of cast steel or iron if i could see a whole one i could make my own with the part i have :}

[fjh]

I took the top of thr=e tranny off and found that the lock out that is applied to the cover with a spring and detent ball was broken in half. it is a rectangle box type mechamism thar the shifter tip goes through. looks like it was desinged so when you use deep reduction the only gear that can be used is 1st gear. so i popped it out and now i have deep reduction. Hmmm wonder where the broken piece is Yuk Yuk going to see if i can find one somewhere, man it is a flimsy piece made out of some kind of cast steel or iron if i could see a whole one i could make my own with the part i have :}

Hmmm wonder where the broken piece is

Check the drain plug!