Trans Case wont engage 4hi/lo

[dodge123]

263hd (np1) replaced last october less than 6k since install

 

I am having an issue with the trans case not engaging 4hi/lo. I have replaced the encoder ring in the encoder motor. When I press either of the 4hi/lo buttons they will blink and I can hear the encoder making noise like its trying to shift positions (not a buzzing sound) but then it defaults to 2hi. I have googled the hell out of this and I know I need to get the TCCM scanned. I have tried pulling fuses and disconnecting batt.

 

Would the 4x4 actuator have anything to do with this? Can I check resistance?

 

My fear is the linkage in the trans case may be binding. I loosened the spring and poppet next to the encoder and tried to manually change the position with an adjustable wrench but it wouldn't budge. Maybe I wasn't using enough force but dont want to break it.

[gmtech4]

shifting a t case with the encoder off is a good idea however you have to have trans in neutral and all tires off the ground so you have ZERO driveline stress ,,,turning driveshafts slow while shifting helps ..

 

if it still wont shift while you do the above the t case has to come out and apart for an estimate

 

scan it first ,dont worry about resistances just yet lol

[dodge123]

I removed the case tonight shortly after posting. I haven't opened it up yet (went for wings and beers with some buddies) but I got the job down to 40 minutes. I cant wait to find out how much this will cost.

 

I pulled the bed last weekend thinking I could replace the fuel pressure regulator only to find its a returnless system and the sensor would need replaced instead. Unless I missed something the pressure of the system charges up to 52 psi then when shut motor down slowly starts dropping after a few minutes.

[txab]

Pressure should be more like 55-62. 52 is too low

[dodge123]

So ill need a new fuel pump soon.

 

Update on the trans case:

The story here is I ordered the reman case from drivetrain.com last sept. I bolted it in and put the original driveshaft back on not thinking the worn driveshaft slip yoke would damage the new t-case. Well it burned up the aluminum bushing the first day of driving. I pulled the case apart and had a new bushing installed in the rear case half, locally and had the driveshaft yoke replaced, u-joints and balanced. Since then I have been driving in 2hi and the truck wont engage 4wd at all. I know the encoder motor works.

 

Tonight after talking with tech support I figure "what do I have to loose?" Since I had opened the case anyway the warranty no longer applied and I am a few weeks past due (no big surprise). I begin removing the snap rings and pulling the gears making sure to put them in a clean box in the same position I removed them. I noticed that one of the gears riding on the main shaft didnt line up with the one above it, (this must have happened the first time I pulled the case apart) I pulled the main shaft out and re-aligned the gear put everything back the way it came apart and what do you know I can shift the case manually with an adjustable wrench now! So while spinning the main shaft (all back together) I notice it has a very slight visible wobble. No wonder why the bushing in the tail housing is ruined. This must have happened the first day of driving with the orig. driveshaft.

 

I want to believe that if I install a new mainshaft, the gear i found to be misaligned and bushing and replace the driveshaft yoke and rebalance it I will be ok. This reman case has less than 6k since new last sept. Can I get away with that? I will obviously need to flush it best I can prior to reassembly.

[dodge123]

I put the main shaft on a buddys lathe to check run-out at each end. 0.0025 and 0.0030 We could actually see the shaft wobble. I was told by tech support at drivetrain.com the absolute max run-out should be 0.002-0.004.

 

[ujtruck]

what is the run-out near the chuck(spindle)?

 

and ask buddy to put this on 3 jaw chuck - test run-out with high speed -

 

even brand new lathe have the spindle runout at .0003, i never seen .0000 - at this point you can use 4 jaw chuck and good dial indicator, but you won't get .0000

[dodge123]

Are you saying the lathe may give an inaccurate reading? We actually went to his work (plastic CNC machining) and used the machine there. He showed me the calibrated rod with a runout of +/- 0.001

[ujtruck]

Are you saying the lathe may give an inaccurate reading? We actually went to his work (plastic CNC machining) and used the machine there. He showed me the calibrated rod with a runout of +/- 0.001

 

 

Yes, but now you have use CNC which is pretty good