Diagnostic advice request. Transfer case or transmission broke?

[Yoopercharged]

Looking for advice please. My 06 Denali (NR3 4L65e) lost power to the ground in all gears, forward and reverse, after pulling out into traffic. Park still holds and there's some awful noises when the engine is running in park, neutral, or gear. Transmission fluid looks and smells fine. It's currently on a trailer and haven't had a chance to pull any driveshafts. Any help or advice would be greatly appreciated. Thanks.

 

[Doubeleive]

Looking for advice please. My 06 Denali (NR3 4L65e) lost power to the ground in all gears, forward and reverse, after pulling out into traffic. Park still holds and there's some awful noises when the engine is running in park, neutral, or gear. Transmission fluid looks and smells fine. It's currently on a trailer and haven't had a chance to pull any driveshafts. Any help or advice would be greatly appreciated. Thanks.

sounds like pump/tc took a dump
the transfer case doesn't move while in park

 

[strutaeng]

That's the AWD TC, right? No option for Neutral? Have you tried manual 1 or 2?

Yeah, I agree with @Doubeleive Sounds like a catastrophic failure of the transmission, possibly pump and geartrain failure. May want to drop the pan to see what it looks like.

 

[Doubeleive]

usually the transfer cases are pretty stout, so that makes it even less likely

 

[Yoopercharged]

That's the AWD TC, right? No option for Neutral? Have you tried manual 1 or 2?

Yeah, I agree with @Doubeleive Sounds like a catastrophic failure of the transmission, possibly pump and geartrain failure. May want to drop the pan to see what it looks like.

Yes, no neutral. I don't think I tried 1 or 2.

 

[Yoopercharged]

Thanks much, I will check it out. I was originally thinking/hoping for the xfer case, but the more I thought about it, probably the transmission. I'll try to follow up here when I get it figured out.

 

[strutaeng]

Thanks much, I will check it out. I was originally thinking/hoping for the xfer case, but the more I thought about it, probably the transmission. I'll try to follow up here when I get it figured out.

I believe 2006 may have been a transition year were the Input Speed Sensor (ISS) was introduced on the 4L60/65e? If you could get ahold a scanner that has live data, it should provide information if the input/output shafts of the transmission are spinning or not. I think even the pre-ISS model should show that the transmission shaft is spinning or not, to rule out a bad transfer case (less likely the case).

Have you scanned it for any codes?

@NickTransmissions may offer some advice as well. He's our transmission expert on this forum.

 

[NickTransmissions]

Looking for advice please. My 06 Denali (NR3 4L65e) lost power to the ground in all gears, forward and reverse, after pulling out into traffic. Park still holds and there's some awful noises when the engine is running in park, neutral, or gear. Transmission fluid looks and smells fine. It's currently on a trailer and haven't had a chance to pull any driveshafts. Any help or advice would be greatly appreciated. Thanks.

Check fluid level if you havent done so already. If its way over full and level doesnt drop when you fire up the engine, the pump is shot and trans needs to come out.

 

[Yoopercharged]

Check fluid level if you havent done so already. If its way over full and level doesnt drop when you fire up the engine, the pump is shot and trans needs to come out.

Fluid level was good and didn't smell burned, but didn't check while running. I haven't scanned it yet. It makes some awful noises when the engine is running, like a shaft or something is broke and clanking and banging around. I'm at home, 120 miles away from it at the moment.

 

[mrhp]

The convertor most likely came apart and sent debris through the trans.

 

[strutaeng]

OP has a 4L60. Anything is possible, but torque converter failure is not common AFAIK on those.

 

[Yoopercharged]

OP has a 4L60. Anything is possible, but torque converter failure is not common AFAIK on those.

4L65e

 

[Yoopercharged]

@NickTransmissions Any idea if an 02 sierra 4l65e quadrasteer transmission would interchange? I can start a new post if requested.

 

[strutaeng]

Here's a post I've shared many times on compatability years:

What year transmissions interchange 100%? - LS1TECH - Camaro and Firebird Forum Discussion

Automatic Transmission - What year transmissions interchange 100%? - If I need a new 4L60e or one from a salvage yard, which years interchange electrically (same plugs and pinouts)? For example, if I had a 2002 model originally, would a 2008 one bolt and plug right in? Same question for a 4L65e...

ls1tech.com

 

[NickTransmissions]

@NickTransmissions Any idea if an 02 sierra 4l65e quadrasteer transmission would interchange? I can start a new post if requested.

Why not rebuild your unit or have it rebuilt by a competent shop?

I never recommend buying used transmissions (or reman units, for that matter), especially if your engine has been upgraded to make more power...Only potential exception would be if you plan on dumping the vehicle immediately afterwards.

 

[Yoopercharged]

Why not rebuild your unit or have it rebuilt by a competent shop?

I never recommend buying used transmissions (or reman units, for that matter), especially if your engine has been upgraded to make more power...Only potential exception would be if you plan on dumping the vehicle immediately afterwards.

I agree. Lack of funds and time/logistics. I found a used one with 80,000 for $450 with a tcase but seller changed their mind and decided to keep after inquiring. Merry . Was thinking about putting a used one in temporarily and rebuilding the original.

 

[kurtibm]

Noise (clanking, etc.) when running/parked? Potentially a flexplate?

 

[Grayswander]

Looking for advice please. My 06 Denali (NR3 4L65e) lost power to the ground in all gears, forward and reverse, after pulling out into traffic. Park still holds and there's some awful noises when the engine is running in park, neutral, or gear. Transmission fluid looks and smells fine. It's currently on a trailer and haven't had a chance to pull any driveshafts. Any help or advice would be greatly appreciated. Thanks.

Sounds like you're input shaft is no longer connected to the input drum.

 

[Yoopercharged]

I was able to get to the truck yesterday (it's 120 miles from my house) and found that Park was NOT holding. It was kind of but would jump out easy. Found some internal splines stripped out on the transfer case planetary F/R gear set. There was some transmission fluid that leaked out when I spilt the xfer case from the transmission. I assume a little bit is ok? I pulled the transmission pan and it looked free of any contamination.

 

[Doubeleive]

Why not rebuild your unit or have it rebuilt by a competent shop?

I never recommend buying used transmissions (or reman units, for that matter), especially if your engine has been upgraded to make more power...Only potential exception would be if you plan on dumping the vehicle immediately afterwards.

well when a person "maybe" has $500 to spend and a used transmission is $650 you gotta do what you gotta do..........
there have been plenty of times I had no option but to go used or learn to do it myself for cheaper or be homeless....