Every now and then...2nd/3rd/2nd/3rd

[Dan K]

Just at part throttle while cruising the trans in the GN will upshift into 3rd and then it seems to get a little confused. It tries to downshift to 2nd then back to 3rd then back to 2nd. WTF?
I don't let it get too far, I always get out of the throttle and let it pick a gear. It'll usually settle in 3rd but as soon as I get back in the gas it kicks back down to 2nd and shifts to 3rd when it should and is fine again.
This only happens every now and then...but it's really got me confused.
Trans has 38k miles on it, fluid level and condition are good, tv cable is adjusted right, has a PTS shift kit and pressure regulator system, and shifts really nice at part throttle and wot throttle.

Anyone know why it's doing this? Is this a sign of something starting to fail?

 

[chris718]

LOOSEN THE TV CABLE 2 CLICKS AND SEE WHAT HAPPENS .THE FACTORY OPENS THE WOT DETENT CIRCUIT SLIGHTLY BEFORE WOT SO YOU HAVE SOME ROOM TO GO UP AND DOWN EVEN AFTER USING THE MASH IT TO THE FLOOR AND LET IT PULL OUT METHOD OF ADJUSTING THE CABLE.

 

[Dan K]

I'll loosen it and drive it this weekend then. Thanks Chris!

 

[RareT]

Could this be the TCC switch engaging/disengaging?

Ed

 

[77 cruiser]

I too have the same prob. doesn`t do it all the time. I`ve tried adjusting the TV cable too just seems to change what speed it does it at. All I`ve got is a code OG.

Jim

 

[87LtdT]

Same thing happened to me after my shift kit install....only happened at low throttle/speed...things had to be just right.

Lonnie Diers explained to me how the shift kit removes the "overlap" which exists in stock trans. Something about the stock trans has a bit of overlap in which the trans remains in 2nd for a small time while shifting to 3rd....makes the shift smoother. Shift kits remove this overlap....which results in the jerky 2-3-2-3-2 shifting if the conditions are just right.

Hope I explained it correctly.

Bob

 

[Dan K]

Originally posted by 87LtdT
Lonnie Diers explained to me how the shift kit removes the "overlap" which exists in stock trans. Something about the stock trans has a bit of overlap in which the trans remains in 2nd for a small time while shifting to 3rd....makes the shift smoother. Shift kits remove this overlap....which results in the jerky 2-3-2-3-2 shifting if the conditions are just right.

My car still does it. I might take 1 more click out of the TV cable and see what happens.
Sounds like from what Lonnie told you there isn't much I can do about it.

 

[87LtdT]

Yes you are correct. It is just a fact of life. If it happens to me I just add a bit of throttle and it goes away. I re-read my post and it appears that Lonnie told me of the "overlap" after he installed a shift kit. That is not what happened. Long ago, I had a Kenne-Bell shift kit installed by a local guy, and later noticed if things were just right the 2-3-2-3 thing happened. About a year later, when I first met Lonnie we were talking about transmissions and he then explained the "overlap" to me. Said it smooths the gear shifting process.

Over the years he has also cautioned me on TV cable adjustments....ie don't get too far from nominal setting.

He knows so much about transmissions that if he told me to put it in backwards I'd try . I wish I could do a better job of explaining what he explained to me.

I'd HIGHLY recommend him for your trans work...he's in Cincinnati.

Regards, Bob