p1721 trans concern

nasty6.6

yes sir......
Mar 22, 2009
123
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San Angelo, TX
OK I had a dtc pop up today and truck act really funny. It did this a while back and feels like the clutches dont engage when going into third BUT when you get the truck to down shift into third it sticks fine. Well that went away and then today it came back but the dtc is a p1721 but does it in fourth gear now with the same concern and when it down shifts from 5th to 4th it sticks fine on the highway. I dropped the pan and found very very little material in pan plus fluid doesnt smell burnt and looks really good.

trans is a built suncoast and only has around 15k miles could this be a solenoid acting up? It is very random but then once it starts acting up it will act up for a day and then goes away for a few weeks and its fine again... Any input would be helpful was going to try and sell to buy a crewcab but need to fix first!
 

jc1843

New member
Sep 27, 2009
228
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86
So Calf
When you have a solenoid code-- it is rarely the solenoid. The TCM sends a signal to the solenoid, and that should open/close a valve in the valve body. If the TCM does not see the proper results, it will set a solenoid code. When the problem may be a stuck valve. :)