Do I have a bad transfer case input seal?
 

Hello all

On my 2002 Zr2, I recently went through the whole issue where I had problems with vacuum leaks from my HVAC selector knob.

In reading much about this, I learned about how fluid overfilling the transfer case, then getting into the vacuum switch, is a common reason for this and yes, I think that is what happened.

Then in a next bit of fun, in a attempt to replace the vacuum switch I actually stripped the darn hole in the case. Btw in my defense and I did confirm this via a dial caliper, the A/C Delco switch I got it just a hair smaller by about .10th of a mm. OD of threads on old & org one measures 15.66mm, new A/C Delco is 15.56mm. May not seem like a lot but can feel the dif in a fitting an I think it was just enough that when I wrenched on this, it started the stripping very easily, which since I didn't suspect, I just kept tightening until it was to late.

Anyway, so now I had to remove the transfer case to repair this which is another story, but on the subject of where all this started....

...am I correct in understanding that if anything it could be that overflows the transfer case, it is the "Input Shaft Seal" of the transfer case that is the problem?

So that would be in this diagram of my NP233: TRANSFER CASE (NP1)(NEW PROCESS | Nalley Buick GMC Brunswick part in the pic numbered 42, which is GM part number: 14095609 ?

If this is correct, is that the only part I would need to replace to directly fix this issue as since I have the case out for the hole repair I might as well replace that.

But just want to make sure this is the fix.

Btw, one other related question I had, when I separated the case from the extension, there was a good amount of ATF that came out of the section, is that normal or is there some other seal that might be bad?

Thanks for any help.

Looks like you have the right PN on the seal, and ATF in the T-case adapter is normal... 4x4 4l60's don't have an output seal, so the only thing sealing tranny fluid from the T-case is that input seal, hence the issue with overfilling the case when they go bad. Just a heads up you'll also need some RTV to reseal the aluminum piece that the seal pops into (number 44 in that diagram), and a new gasket (or the RTV) to seal the t-case to the trans adapter. Sounds like you're on the right track tho, good luck.

Thanks greatly for the reply KM346.

Yeah, I was looking at the plate (#44) both in the pic an on the TC, and see there is no gasket, funny...would be a good place for one but guess there is a reason. But see that it has & needs something. Actually I was wondering as its been so long since I worked on stuff like this, if RTV is what is best to use?

I was at the hardware store today and they had red, blue and black RTV Silicon Permatex, an then some Permatex called Form-A-Gasket, with one saying it got hard, and other not. So I picked up the not get hard version as I wondered if RTV is what they used on that plate, as seems with no gasket, it might need something stronger then RTV.

Any thoughts on any of that?

From what I've seen the different colors/types have quite a bit of overlap for intended uses. It makes my head spin trying to compare specs on the back label on some of them. As long as its an automotive sealant rated for oil / heat I'd run it with confidence. I do refer "The Right Stuff" made by permatex to any of the ones you listed... but it is expensive.

Checked out that The Right Stuff product and sure looks like the closest thing to the factory stuff, plus 1 min cure time...looks like its worth it.

Just ordered up some.

Thanks for the heads up

BtwKM346, checked out the trucks in your garage, 4Dr blazer (aside from custom stuff) looks very much like mine. White Zr2 (2dr as they are) an with only 50k on.

But yours look great, really like the full leaf spring treatment, must be a blast to drive.

Thanks for the compliments! Its been a fun project for sure, and trust me i drive the wheels off it.

when I swaped out my transfer case it had a gasget and as normal it fell apart and nobody carrys one - I taped mine out the old school way with a small ball peen hammer out of bulk gasget material [makeing gasgets yourself is a lost art] - I also lightly coated it with RTV black