No 4lo

cumminstroked

cumminstroked

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Dec 7, 2009
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I have a 99 F250. If refuses to engage into 4lo. Its an electric shift t-case NV273. I replaced the shift motor on the case and nothing changed. What else could be causing this issue? I don't want to just start replacing parts until I find it. Any help would be appreciated

Thanks
 
It was having this issue before i replaced the shift motor or the cummins conversion too. I replaced the shift motor because it was cracked and no longer worked and the cummins conversion because it sounded like fun... Anybody have any ideas on what could be the issue?
 
I have heard this before. I'm not even sure where the module and how to test it... Mo Smoke could you get me on the right track here?
Thanks
James
 
See it the GEM has codes. Does it go into 4x4 high ?
 
Yes it goes into 4hi no problem at all. But 4lo i get nothing. I tried about everyhting on it... Held the break with the clutch in. Neutral and a few different gears. Rolling slowly in forward and reverse. Hubs locked and unlocked. I figured it would be the switch on the dash or the module. It did this before I did the 12v conversion on it too at the time it just wasn't a big deal to take care of it but it is now lol.
Thanks
 
Look closely @ each pin on the transfercase connector, I have had the plastic melt around the pins on the connector so they can look ok but not make connection. It was on a 05 but I think they are the same style connection.
 
I will have to take a look. Its a little tough to do some trial and error right now, my truck is in about half a million pieces and I'd like to get some of my bugs worked out while i'm waiting on the rest of my parts which will be here at the beginning of next week!!!!!:woohoo::ft:
 
Okay My truck is all back together now. I cleaned all the connections on the t-case plugs and still no 4lo. It goes in to 4hi though no problem. The 4x4 module... Where is it located and how can I test it? That is the next step i figure.
Thanks
 
The 4x4 module is behind the glove box. You have to take out the glove box access it.

I have heard of wires corroding and breaking for the transfer case. There was a thread about it on psn. They showed pics of corroded wires on the drivers side inner fender well. Mine is doing this also and I believe this is my problem.
 
I know the trans needs to be in neutral and foot on the brake. the MLPS has a seperate set of contacts just for the shift on the fly 4x4 low circuit.
 
The Fummins I bought the wiring was hacked to hell. Is there anyway to bypass the switch on the dash. Like splice into the actuator and have a switch for 4hi an 4lo? Also if this can't be done can't I take the tcase to a tranny shop and have them make it a manual tcase?
 
No you can't. there is contact plates inside the t-case that tell the computer when to stop the forward or backward relays. there is no hi and low relays just one that moves the fork oneway and another that goes the other way.
 
Mo Smoke said:
No you can't. there is contact plates inside the t-case that tell the computer when to stop the forward or backward relays. there is no hi and low relays just one that moves the fork oneway and another that goes the other way.
Click to expand...

Im a little confused by this. When u say no is that a no to wiring up a 4hi an 4lo switch? Transfer cases are new to me. I have always had a lever to yank on not a button. Can a tranny shop replace the actuator with a lever? Thanks
 
That is correct. The relays you see under the truck move the servo either forward or backward. If you really have your heart set on it go for it but it will yeild you either 2wd or 4lo because those are the 2 extremes of each end of the tcase shift. also after about 10 min it will catch the servo motor on fire from being powered all the time.
 
Ok I understand. So the best route will be to get a tcase with a lever instead of the electrical bs? It should bolt right up correct, just need to put a hole in the floor?
 
It will bolt up, converting a S-O-F to manual requires different internal and external parts.
 
wow I sure missed a lot while at PCB. Is the module used to go into 4hi? Does anybody have any more info on the broken wiring by chance too? Thanks again guys
 
So finally got some time to do some looking around, Is the module the little white plastic box behind the glovebox? It sits right on top of some heating and air duct it looks like. Has one blue plug going to it and it looks to have about 4-6 wires into the plug. If i remember I'll get a pic tomorrow. If this is it how can I test it?
 
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