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Discussion Starter #1 (Edited)
My 2000 Yukon XL 4x4 1500 won't shift into 3rd gear. Everything was working fine, we went into a store and then when we left, no 3rd gear. The tranny fluid is full and I don't see any leaks. I have tried all gears on my column shifter but it won't go from 2nd to 3rd. There has been zero noise, difficulty shifting or any other indicator that there may be a tranny issue leading up to this. It shifts perfectly from 1st to 2nd but that's it. Reverse works fine also. I took it up to about 80km/h (50mph) at 3500rpm-4000rpm but no shift. When I let off the gas, there is no engine braking either, almost like I am in neutral. I hooked up my OBD2 and the only code I got was P0440 (EVAP control) which would not be related to my transmission issue. I think it could be a A/T control solenoid, but any other thoughts? Any idea how to confirm/rule out a solenoid? Thanks in advance for any help!
 

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The shift solenoids for the 4l60e are cheap last time i did one and easy to do. Drop the pan and both are mounted on the VB in the rear. What i would do is ohm out the trans harness and if it checks out throw a new solenoid(s) in there. I think the last time they were like $20.
 

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replace both transmission solenoids. this may correct the problem. make sure you use DEXRON VI not DEXRON III.

If you have had/or have DEXRON III in this transmission and did not replace the fluid every 40,ooomi. chances are the valve body has been damaged by the acidic DEXRON III which is what occurs if fluid changes are not done often with this fluid.
 

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BTW, is there any way to know if you have D3 or D4 in your tranny when you buy a used vehicle??? Jim
 

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Discussion Starter #5
Wasn't the shift solenoids, it was the 3/4 shift plate. Tranny is out and halfway re-built. Thanks for the tips....
 

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never heard of a shift plate. the valve body or the shell has failed / worn .

acidic fluid does this .
 

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Discussion Starter #7
I meant clutch plate...Turns out the shift solenoid failed, so no oil to the clutch plate. It burnt out and made a big mess!
 
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