Np243c transfer case

[svcattle]

I just rebuilt the np243c transfer case in my 96 k2500 i got it re installed but I had to take the motor off to shift the case into 2wd with a wrench so that I could twist the output shaft and line up the input shaft of the transfer case with the transmission . Anyway I got it all mounted and shifted the transfer case back to the position it would line up with the motor and bolted the motor on hooked up the harness plugs to the motor and transfer case I tried shifting it without the engine running and I heard it try to shift so I figure that it would be ok once I got the Trans full of oil and run the engine to help line things up well I filled everything up and started the truck shifted the transmission into gear and I heard the gears grind and then the transfer case shifted into 2wd the 2wd light in the switch came on and now truck would move forward and back but now when I push the button to shift into 4wd the lights in the 4 hi and 4 lo switch flash and I can hear a relay click in the dash but the lights just flash for a few seconds but no transfer case motor noise I tried rocking the truck forward and back a little to see if it would help the transfer case shift but it didn't . Anyway any ideas did I fry my tramssfer case motor ?
Thanks Shaun

[svcattle]

Ok I went back out again when I push the 4 hi switch nothing no light flashing or anything but when I push the 4 Lo switch the lights will flash then finally the 4 lo Light will come on steady but I have no gears shifting the transmission from drive to reverse I can hear the motor on the transfer case working but I don't think it's going far enough to engage the gears when I shift the transfer case back to 2wd I can hear gears grind and then it will engage 2wd any ideas
Thanks Shaun

[svcattle]

At least I didn't come to a Chevy drive train forum

[trbankii]

Both of mine are manual shift t-cases, so I can’t help you with the electric shift version. Does it turn point-to-point? If so, it may need to be properly indexed if it is not getting to the ends of each point.

I’d start by bench testing the actuating motor to make sure it is working properly.

[svcattle]

Thanks for the reply ya I can shift through all the ranges with a small crescent wrench I bought a new motor and installed because the original wouldn't not shift at all the new one will shift to 4 hi but not lo so I took it back off to make sure that the transfer case would shift through all Ranges manually and it will so I guess I will reinstall the motor and see what happens

[DieselDavy]

I like trbankii idea about having to index the motor when you install it. I'm guessing you have to have it and the transfer case in a known position so everyone is on the same page.
There is probably some installation instructions someone has. Maybe they'll see this and post them.
Good Luck!
Dave

[convert2diesel]

From AllData:

Important:

•If the encoder motor is being replaced because it is defective, ensure that the transfer case is in the neutral position. Manually shift the transfer case at the shift shaft, using a crescent wrench if necessary.
•When installing the encoder motor, ensure that the encoder motor is indexed correctly and the motor is flat against the transfer case before tightening the bolts.
•A NEW encoder motor does NOT come with locating pins.

Bill

[DieselDavy]

There you go SV! Isn't this a great place!
Let us know how it works out.
Dave

[svcattle]

Instructions with the motor said it ships in the 2wd position which it was so I indexed the transfer case shifter to 2wd and the motor bolted right up 2 and 4hi work 4 lo will not work I've got to pull the transfer case off and see what I did wrong when I assembled the case I just rebuilt the case because is a bad input shaft and range hub .
Yes this a great site I guess there aren't that many 6.5 left in the world anymore ?

[DieselDavy]

SV,
I think there are quite a few folks with the 6.5s on the road. This time of year, I think most of them are working their 6.5s instead of here talking about them! Hopefully, someone will be able to help you out with your transfer case problem. I know nothing about them or I'd help out.
Good Luck,
Dave

[convert2diesel]

Instructions with the motor said it ships in the 2wd position which it was so I indexed the transfer case shifter to 2wd and the motor bolted right up 2 and 4hi work 4 lo will not work I've got to pull the transfer case off and see what I did wrong when I assembled the case I just rebuilt the case because is a bad input shaft and range hub .
Yes this a great site I guess there aren't that many 6.5 left in the world anymore ?

From what you are saying, you have both 2hi and 4hi and I assume 4auto. This would seem to say that you have hooked up the shift motor correctly. I have found that in my truck, sometimes I have to have the truck rolling before it will shift into 4lo. This is perhaps your issue.

This was taken verbatim from my owners manual:

"Shifting into Four-Wheel Low

Notice: Shifting the transfer case into Four-Wheel Low while moving at speeds faster than 3 mph (5 km/h) may cause premature wear to the transfer case, and may cause the gears to grind. To avoid causing premature wear, and grinding the gears, do not shift the transfer case into Four-Wheel Low while the vehicle is moving faster than 3 mph (5 km/h).

To shift to Four-Wheel Low, the ignition must be in RUN and the vehicle must be stopped or moving less than 3 mph (5 km/h) with the transmission in NEUTRAL (N).

The preferred method for shifting into Four-Wheel Low is to have your vehicle moving 1 to 2 mph (1.6 to 3.2 km/h).

Press and release the Four-Wheel Low switch. You must wait for the Four-Wheel Low indicator light to stop flashing and remain on before shifting your transmission in gear.

Notice: Shifting the transmission into gear before the Four-Wheel Low indicator light has stopped flashing could damage the transfer case. To help avoid damaging your vehicle, always wait for the Four-Wheel Low indicator light to stop flashing before shifting the transmission into gear.

It is typical for your vehicle to exhibit significant engagement noise and bump when shifting between Four-Wheel Low and Four-Wheel High ranges or from NEUTRAL (N) with the engine running.

If the Four-Wheel Low switch is pressed when your vehicle is in gear and/or moving, the Four-Wheel Low indicator light will flash for 30 seconds and not complete the shift unless your vehicle is moving less than 3 mph (5 km/h) and the transmission is in NEUTRAL (N). After 30 seconds the transfer case will shift to four-wheel high mode."

Hope this helps

Bill

[trbankii]

Yes this a great site I guess there aren't that many 6.5 left in the world anymore ?

Well, the Duramax came out in 2000, so you’re talking about vehicles that are a minimum of sixteen years old. My pair are hitting 22 and 23 years old. The average person just doesn’t hold onto a vehicle that long. In the past week, two friends have made comments about their “ancient” cars - neither of which is even ten years old.

[svcattle]

Well I finally got it figured out I forgot the snap ring that holds the input shaft into the planetary gear so that was keeping the range shift hub from bieng able to engage the planetary for 4 lo . So I get the dummy of the year award . I have a factory service manual coming so that will help a lot next time I need to overhaul something .

[svcattle]

The old shift motor will run when I put power to it with the modulator or whatever removed but won't do anything with it installed and plugged into truck wiring harness