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Issues with transfer case swap

Jorge6.5

Jorge6.5

Well-Known Member
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Location
Upstate New York
Last month i swaped out my np243 case for an np241 t case and had problems with it shifting properly and the speedometer was reading way off. Shifts very hard at high rpm.

Brought it to my mechanic to figure it out and he claims that it will not work right because I don't have the encoder motor plugged in and I call bs on that.

Any suggestions on what it might be? I'm gonna pick it up later and do some checking on the wires and sensors. If I can't figure it out I'm gonna have to it to my other mechanic. Help please
 
I did swapped to a np241 on my 97 truck,and everything worked fine. I just ran a switched ground to control the front differential.
 
With the TCCM still present and not hooked up to the transfer case, who knows if it is grounding the ECM for 4X4, 4 low, or who knows what.
 
I swapped to 5spd at the same time,lots of plugs disconnected,but the speedometer still worked. This was on a gas truck that had a 4l60-e.
 
OK, i disconnected the TCCM and no change. Also unplugged the shift button and again no change. the wires going the speed sensor and t case switch sensors appear to be all good. Im totally lost here, not sure what to do next. I cant understand what could be the problem, everyone else who does the swap has no issues but not me with my luck.

I have a posi lock cable actuator to engage the front axle so the stock thermo junk is disconnected. Will a scanner be able to tell me codes and what is going on with the transmission and t case? Any more suggestions?

Thefermantor, what did you mean about the ecm wiring?
 
Can i have the ecm flashed for a lever t case? Or does the problem lie somewhere else?

I really need this truck working, i just cant get it figured out

can i test the plugs going to the t case switch sensor and vss? This is unreal, its driving me crazy!
 
Speedo reading being way off is the clue. Aren't there two different reluctor and pickup versions between them? Will your old t-case speedo parts swap into your donor t-case?..

Maybe there's a different 'tooth' count on the reluctor that affixes to the output shaft.. And maybe the 'pick-up coil' has a different resistance or something...:dunno:
 
I was under the impression the reluctor wheels are the same between the 2 cases. Actually started a thread in this section asking that.

Gonna have my other mechanic check it out this week along with the original t case.

Thanks for all the suggetions guys.
 
Jorge6.5 said:
I was under the impression the reluctor wheels are the same between the 2 cases. Actually started a thread in this section asking that.

Gonna have my other mechanic check it out this week along with the original t case.

Thanks for all the suggetions guys.
Click to expand...
There was a 17 tooth option for awhile for the reluctor wheel behind manual trans trucks, so maybe you have a 17 instead of a 40 tooth reluctor in your new transfer case.
 
Forgive me for posting this as a first post, but I found this on a google search.
Im having problems with the 4wd on my truck. Its a 98 k2500 with push button 4wd, 2hi, 4hi, 4lo. It will shift into 4lo and 2hi but no 4hi. Being that it does shift I figure it is either the TCCM or the Switch. The two OBDII readers we have wont connect to read the tranny codes. One is MAC the other is a Snapon Solus. Since it wont connect to read(it did before) were thinking TCCM. I have heard there can be a connection issue, corrosion on the connectors. Part of the issue is I dont know where the TCCM is or what it looks like. Jorge I dont want to bogart your thread but you obviously know where it is located and it looks like you may have a switch and TCCM you dont need. Want to sell them? Can you at least help me with where the TCCM is? Thanks
 
Mikeb1 said:
Forgive me for posting this as a first post, but I found this on a google search.
Im having problems with the 4wd on my truck. Its a 98 k2500 with push button 4wd, 2hi, 4hi, 4lo. It will shift into 4lo and 2hi but no 4hi. Being that it does shift I figure it is either the TCCM or the Switch. The two OBDII readers we have wont connect to read the tranny codes. One is MAC the other is a Snapon Solus. Since it wont connect to read(it did before) were thinking TCCM. I have heard there can be a connection issue, corrosion on the connectors. Part of the issue is I dont know where the TCCM is or what it looks like. Jorge I dont want to bogart your thread but you obviously know where it is located and it looks like you may have a switch and TCCM you dont need. Want to sell them? Can you at least help me with where the TCCM is? Thanks
Click to expand...

Sorry, just saw this post now. Check your PMs
 
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