Big hats off to V70tdi - thanks man. I checked my transfer case last night and sure enough there was a damn hole right where you thought it would be. I find it frustrating that Chevrolet no doubt is aware of this defect in the design of the transfer case but has no recall out to correct it. After doing more reading online, it seems this issue is prevalent amongst the Chevy transfer cases NP236, NP246, NP261, and NP263.

Here are some pictures of the rear half of the case:





The one saving grace of this whole thing is that my transfer case has not yet grenaded - so it may be salvageable. If that is the case, all I will need to do is purchase a back-half of the case (available from Dorman on Amazon here for $140: ) and either the BRNY or Merchant Automotive transfer case oil pump upgrade kit), remove the transfer case, pop it open, install the new pump kit and reinstall with the new case backing.

Wow - what a great way to start my first Chevrolet ownership.

 

BTW this is a really helpful video explaining the issue and how to fix it.

 

wow great find! sorry for the trouble. But amazing what this forum is capable of

 

Sad to see that it was the transfercase
But as you say you hopfully find it right in tame to save it with a new case half and take the time to inspect/change the bearings and shaft seals when you dont know how log they been running dry out of lubricate.
Best luck to you with repairing the transfercase and if we are lucky here at the forum you post a DIY of your t-case drop and repair.

 

Thanks. Last night I used a steel brush drill bit to scuff up the area around the hole really well, and applied J-B Weld Industrial (first coating) to the hole and surrounding area.

My thinking is this. After doing a lot of reading on the subject the J-B Weld fix may only plug the hole for 5 miles, or 5000 miles, depending on who you listen to. Yesterday I got quotes from two local area shops for dropping the transfer case (and assuming no critical damage to the internals) to replace the rear back half of the case and install the oil pump rub fix. Both were in the vicinity of $1,000.

After that, I decided that I shouldn't get ahead of myself, and should at least try the $10 fix that has worked for some (J-B Weld), to see how things go. I do believe that over time the oil pump will rub off the J-B weld just as it has rubbed through the transfer case magnesium housing, however, I want to try this approach first.

Since I just bought this car, I am pretty sick of working on it at the moment (have changed most of the fluids, replaced all of the major pulleys, new steering pump (a real PIA), among other things), so the idea of dropping the case myself right now is not appealing.

That said, when I went to apply the first coat of J-B Weld last night, I was surprised that the transfer case on this vehicle is actually pretty accessible (there is a lot of space to get to the bolts where it connects to the transmission). This restored my confidence that dropping the case myself won't be so bad.

I will apply another layer or two of J-B Weld before driving, and then report back how it goes. If it does begin leaking, I will expedite my plans to just do the job right and drop the case.

 

BTW can I get a little friendly outrage here from my fellow Chevy owners? How ridiculous is this that these transfer cases are popping pinholes through their sides left and right? The transfer case shell should never need to be replaced - this is a clear as day manufacturing defect. Sorry just venting my frustration

 

Well I am holding my breath but the J-B Weld appears to be holding (for now) as a patch on the transfer case, and the clicking noise has disappeared.

It was strange. I finally drove the Suburban up the street to the gas station and let it really warm up for about 20 minutes while I put air in the tires. This was the first time I really drove the vehicle any distance since filling the transfer case.

While on the trip up to the gas station the "ticking" noise that started this thread in the first place persisted, on my drive home after the vehicle was fully warmed up the ticking noise was gone!

Additionally, this morning after a 10* ambient temp cold start and a few minutes of warm up, the ticking noise did not return.

My thought is the ticking was transfer case noise, and it took a little bit of driving for the new fluid to fully circulate in the case which has dampened the noise.

I am not naive enough to think my troubles are over - the J-B Weld patch on the t-case is a bandaid and it doesn't change the fact that the pump rub issue is not fixed. I am hoping the J-B Weld holds through the spring/summer, so that when it is WARMER (hate working on the car in the damn cold), I will drop the transfer case, replace the case backing and install the pump rub fix.

Will post back up with any updates on this front. I cycled back and forth through 2Hi and 4HI on my drive to work this morning (we just received about 7 inches of snow here in Northern Virginia and the roads are a mess this morning with the temperatures in the teens), and everything seemed to operate smoothly. Will be continually checking my J-B Weld to see if it is still holding over the next several months.

 

Just a quick update on this thread. With the JB Weld in place and the transfer case filled, the ticking noise has disappeared.

However, the past two days I have noticed the ticking returning - it is almost so quiet your average person wouldn't notice it. I rolled underneath the transfer case this morning and what did I find? Another pin sized hole on the opposite side of the case from the first hole, with fluid dripping from it after driving! I assume the slight ticking is returning from the fluid level slowly dropping below the full line. What a POS design GM!

I plan to clean that hole up tonight and JB Weld it shut and keep an eye on it. Per my prior post, the plan is to drop the trans case this summer and replace the case backing, but the JB Weld on the first hole I patched is holding great so we will see if that ends up being necessary.

 

Outrage supported.