Ian Mills

I have this 12 pin connector that goes to the back of the dual zone climate control module. It seems like there is a loose connection between one or more of the pins on the module and the plug. The screen on the module is intermittent but the blower motor and backlights work even when the screen is off. However, it doesn't seem like I can change the temperature or fan speed when the screen is off so I'm not sure what to make of that. Wiggling the plug or tapping on the screen will usually wake it up for a bit and then the screen will eventually turn off again. A few weeks ago I used electrical terminal cleaner and a little bit of dielectric grease but that didn't help much. I would like to take the connector apart and gently squeeze each of the pin barrels with a pair of pliers to try tightening them but I can't seem to get the pins out. I'm sure there is a proper tool for this but I don't know what this style of connector is called to search on Google/Amazon. If you think I'm chasing the wrong problem, I'm also happy to entertain other suggestions. For reference: this module was rebuilt in 2020 and has worked well since then.

I have a significant leak on the driver's side of the block. The oil is present above the rear main (replaced in 2022) and also above the oil pan gasket. It kind of looks like it's coming from the plug in the pictures which is on the driver's side at the back of the block about 3 inches above the oil filter housing. The block off plate for the optional oil cooler (I think) is visible towards the bottom of the second photo. The block and heads are dry and (relatively) clean above what can be seen in the photo. I don't see anything coming from the oil pressure sending unit (replaced in 2021). The plug with the wires coming out of it is what I have been calling my block heater, however I've been googling around and it seems like a traditional block heater would be in a freeze plug on the passenger side of the truck. The first question is: is this a block heater that goes into the oil gallery or should that be a coolant passage in that location? The second question (related) is: is that where the leak is coming from? I could be convinced that it's the oil pan gasket but the oil starts about 2 inches above the gasket and that seems like too much to me. Happy to entertain theories and ideas. Thanks in advance.

I'd be surprised if a whole new transfer case is cheaper than an input shaft and a set of clutches and steels. I'm sure it would be easier but I'm more budget-constrained than time-constrained

The question I actually have is about transfer case/trassmission interfacing. I was hoping to confirm that the 32 spline transfer case input shaft is a drop-in replacement for the 27 spline shaft. I'm hoping I don't also need to buy the low range planetary set but if I do, I would want to know before I had the case apart on my bench

Right, yeah. I used the wrong acronym. I do expect to eventually tune the truck (if/when I install the manual, I'm pretty tired of my 4l60e) but I've been reading other forums and it seems like other people who swap manuals into their GMT800 trucks have very few electrical problems even before the tune

Well the heated seats are controlled by the seat module in each front seat I believe. For the doors, have you tested the door sensors?

Like Swathdiver said, it could be warped but in most cases you could have a passable solution with just new gaskets (and bolts in this case) As far as replacing the manifolds, if I was going that route I would get some shorty headers that bolt up to my Y pipe.

Oh hmm... if they turn off at all that makes me less confident in my guess but I would definitely give that a look before replacing a module

It could be the module but my first guess is actually the switch. The contacts can corrode and basically "weld" themselves together. Many of the switches on a GMT800 can be opened and cleaned, you could give that a shot before paying for a new switch

Is this affecting both the driver and passenger seats exactly the same way?

That code is interesting because it's just check circuit for the PCM. I would check: 1) The plug for the PCM is properly connected and not leaking water into the connector 2) The ground for that section of the harness is secure and not rusty 3) There's not a place where the wire loom is worn off or burned off where water could come in and short the wires. Other than that it could be a faulty wiring harness or PCM but the fact that it's weather sensitive leads me to wonder if it's a poor connection exacerbated by water

Well I'm not planning going to an 80. I'm scoping out going to a NV4500. I've seen that if you leave the PNP switch in Park, unplug the 20 pin, and seal it up with a plastic cover, the TCM basically just thinks nothing is up. The VSS is in the transfer case so not an issue there. The transmission temp sensor (on 4l60e only) and the reverse lamp switch on (NV4500 only) might give me some grief but I'm doing research still.

Upon further research, I think it looks like the 32 spline input was installed in NP246 cases hooked up to a 4l80e in the 6.0 trucks. That means the 32 spline end would work with the NV4500 correctly but I still don't know if the planetary end of the input shaft is the same. NP246 cases with the 32 spline input are technically called NP246HD...

If you have a multimeter that measures amps and milliamps, the procedure to test for a draw is: 1) Run the truck for a few minutes so that the alternator has a chance to fully top off the battery 2) Turn off the truck, take the key out, pop the hood, shut all the doors and lock the truck 3) Wait a few minutes 4) Turn on your multimeter to the highest capacity current measurement it has 5) Loosen the negative terminal of the battery (being very careful not to disconnect it fully) 6) Touch one multimeter probe to the negative cable, and one to the negative terminal of the battery 7) Keeping the probes in tight contact, remove the cable from the battery If the multimeter reads 0, move it to the next most sensitive setting. Repeat until on the milliamps setting. 9) A normal draw would be in the ballpark of 50 milliamps or so. If you have significantly more than that then you should have an assistant remove fuses one at a time while you hold the probes and watch the meter.

Just to clarify: The manifold itself is leaking? A more common failure is the gasket between the manifold and the head. Replacing the gasket is definitely cheaper and easier than replacing the manifold

My 4l60e is starting to show its age a bit. Not ready to condemn it yet but it occurred to me that it would not be too difficult (on the scale of trans swaps) to put a NV4500 from a GMT-800 HD truck in place of my 4l60e. I've done a bunch of research on which part numbers I would need and it seems mostly manageable but I have run across something I can't find the answer to online. My NP246 transfer case has the 27 spline input shaft because it's currently hooked up to a 4l60e. The NV4500 has a 32 spline output and was never (as far as I can tell) offered with a NP246, just the NP261 it seems like. However there's a part number for a 32 spline input shaft for a NP246. If I install that input shaft, will I be able to put my NP246 behind a NV4500?

Unless you're planning to do a rebuild yourself, I think you have basically two options: 1) Go to a reputable transmission shop and get a rebuild 2) Go to a junkyard and get a similar transmission from a similar truck and swap it in

More than likely it's a bad oil pressure sending unit and the truck is fine to drive. However, if it was my truck I would be nervous about driving (especially towing) without doing more diagnosis first.

I have a similar, but intermittent issue. I'm interested to hear what you discover

I had the same issue this morning with the voltmeter showing significantly below 14. I read the voltage and it was 12.8. However, I turned the truck off and back on and the voltage was 14.7. Would this be fixed with a new alternator? The current alternator is only about 6 months old (Ultima R110073A)

So I'm trying to chase down some sort of electrical issue that results in lost communication and low voltage codes intermittently. I had previously suspected a bad ground or failing module but today I was driving, CEL came on, and I noticed that my voltmeter was hanging out at <12. I pulled over (the gauge came up a bit right when I came to a stop) and read the voltage at the battery and alternator with my multimeter. Both were reading between 12.9 and 13.2. That's not right... right? The other questions is: is this another symptom or is this potentially what's causing all my communication codes (U1041, U1026, U0101, etc.) and low voltage codes (P0332, P0327, etc.)? How low would the voltage need to dip momentarily for the computers to start throwing codes like that?

I got a freeze frame of the P0332 code from my scanner (innova 5410) The pictures didn't turn out well so I'm just going to type out the results. This occurred after driving on cruise (set to 68) for approximately 10 minutes and then cancelling by tapping the brakes lightly and coasting. Do any of these look off? Fuel Sys 1 - CL Fuel Sys 2 - CL Calc Load - 13.7% ECT - 203 F STFT - B1 0.0% LTFT - B1 0.8% STFT - B2 0.8% LTFT - B2 3.1% MAP - 6 inHg Eng RPM - 1603 Veh Speed - 63 mph Spark Adv - 27.0 IAT - 70 F MAF - 1.21 lb/min TPS - 14.5% The other issues are still happening intermittently. This is by far the most common symptom, I cant figure out why it's happening. I rechecked the connection where the Knock Sensor harness plugs in the main harness, I rechecked the main harness ground to the firewall. Edit: The truck also threw a P0327 which (along with the other above symptoms) leads me to believe that it's not just a faulty replacement knock sensor

Could be the ignition tumbler, could be the key itself. It's hard to say without more information. Do you have a second key that acts the same way?

Without any more info, I would probably check the encoder motor on the TC. The encoder on the NV246 has been known to slip out of position

It kindof sounds like your transfer case is slipping into neutral. Have you done any investigation while it's not working properly to check if it is the transfer case? Also, what does the 4WD button or lever do during this? Anything?