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Shift happy transmission?

noJeepshere

noJeepshere

I Drove Trains!
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On a recent trip to Utah, my dad's 2005 Chevy Suburban displayed a very annoying trait. It would downshift for a grade, but if it didn't catch up to speed fast enough (steeper grade) it would go all the way to 2nd gear and catch back up, then shift into 3rd again and hold that. Is that normal? My 99 Yukon shifts less and holds gears better than this does. Is there anything I can do to fix that? either with programming or adjusting something in the tranny itself?

This is highly annoying.
 
If you had the cruise set that's what it will do. Trying to maintain that speed at all costs. My K3500 does it a little but if it's going to be up and down hills I just kick it into 3rd and take it off cruise.
 
black bear performance can change/clean up the shift points and give you a little more power and economy. I would send him an email and ask if he can help. Don't expect a very detailed response though, he's no good at that. Nelson, pcm for less, westers etc. all can do the same thing. Not sure if it would help but I'm thinking it would.
 
Avery4jc said:
If you had the cruise set that's what it will do. Trying to maintain that speed at all costs. My K3500 does it a little but if it's going to be up and down hills I just kick it into 3rd and take it off cruise.
Click to expand...
Thing is my Yukon has never done that, even towing a trailer (albeit a light one)

But this was on grades that their old Suburban never did and my Yukon never would either.
 
GsxrMike said:
black bear performance can change/clean up the shift points and give you a little more power and economy. I would send him an email and ask if he can help. Don't expect a very detailed response though, he's no good at that. Nelson, pcm for less, westers etc. all can do the same thing. Not sure if it would help but I'm thinking it would.
Click to expand...
A search by that name yielded nothing... little help possibly?:dunno:
 
1/2 ton 05 i'm guessing? The motor/trans combo in those trucks is built to REV, and the trans is programmed accordingly. To someone used to driving an older rig, it seems to shift too much. Really, i'm guessing all is well. Just plant your foot, and don't worry too much about it shifting.
 
For what its worth, my C6 in my F250 started doing that.
It seemed good and strong, didn't notice any slippage, but it would downshift under the slightest load. Only down to 2and in a 3 speed, but still should not have to do that.

I checked the vacuum modulator, kickdown lever, nothing. Finally took it to a transmission guy I knew.
Turned out when I knocked the line to the cooler loose during hunting season and lost most of my fluid, I burned the clutches and I had to get a rebuild.

He may have been lying, I still don't understand why it was downshifting unless there was some slippage I did not notice and that was causing it.
But, he had a deal where when his re-builders were idle, he would have them rebuild junkyard trannies or leftovers and put them on the shelf.

He had one to fit my truck on the shelf. $600 flat rate, and I drove it home the next day.
Its got over 100k on it now, so I'm not gonna gripe.
 
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