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Transmsision shift problem

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NV4500 rebuild lost 3/4 gear

Cruise control problem

JScelso

TDR MEMBER
My 1999 3500 with a 5.9 engine just started not shifting into 4th gear and overdrive. I drove around a bit and it shifted correctly 2 times but then went back to the problem. Nothing has been done to the engine or electrical but I just serviced the fuel and oil filter. Wondering if I moved something I shouldn't have as it worked perfectly before that.
 
Fuse gone?
Sure sounds like it, or the Transrelay that feed power to the solenoids.

OD and TCC lockup are both commanded electrically, if both refuse to work at the very same time you have to dig into that.
 
Does power reach the transmission? Check at at the connection to the transmission itself.
Get a service manual to know which pins you have to check.

Just to say, these trannys are fairly simple and quite easy to diagnose compared to modern one.
 
I have a manual but for the life of me can not decipher the diagrams. I found power on the green cable with the ignition on and the green and black and white cable with the trans in drive. The lavender cable has no power at any time. Are there other wires I need to check, and wonder why the lavender cable has no power.
 
Okay, disregard the last post which makes me feel pretty dumb. Got back under the truck and found the appropriate connection and checked for power and there is none, ignition switch off and on, and trans in drive or park. I believe you may have something to provide with the correct info, and thanks for your help.
 
Jumper the relay and check again for power.
With the relay installed there should be power feed to the transmission as soon as the engine is running.
The solenoids in the transmission itself are switched by ground connection from the PCM.
 
How do I jump the relay, there are 5 terminals. There is power to 2 of the slots and I do not know where the other 3 go although it looks like one of them is blank.
 
Does your A/C work? If it does, swap out the A/C Clutch relay with the transmission relay. If the A/C still works, the relay is good. If the transmission still has no power, you have a wiring problem.

All those relays are the same as long as it will plug in.

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Per the diagram that @BigPapa supplied, the terminals are labeled the same as any standard 5 pin relay. If you'd look at the bottom of most relays, they give terminal numbers that then help with how they work and where power goes when energized. Step back and look at the bigger picture. That site really helps with how relays work. Hope you get it figured out!
 
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