Confused, leaking NVG149 T/C

[analyte]

I'm slightly confused and getting somewhat frustrated. I bought my Denali earlier this year, and it was running great with no problems. I was trying to diagnose a vibration/noise after awhile, and the local GMC dealer said it was the T/C and it needed rebuilt. I got the T/C rebuilt by a GM tech friend with all new bearings, seals, and chain. Since that time, I've been trying to figure out why I continue to have a T/C leak.

 

When I reinstalled the T/C, I filled it with just over two quarts of Mobil 1 ATF. The T/C began leaking after the first drive as I could smell the ATF and the leak was present on the underside. I thought I had just overfilled it, so I checked the level daily for two weeks to see how much it dropped off. it finally stopped leaking when I dropped from around 1600mL to around 1125mL as drained from the T/C. I refilled it again with new M1 ATF, and it again started leaking until around 1125mL give or take.

 

The yoke doesn't have a groove or wear marks, and the seal continues to look brand new when checked. It only leaks when driven so could pressure be building up in the T/C pushing ATF out?

 

Any advice on this issue or possible causes? My T/C did not have the weep hole from the pump rub, and I had the kit from Merchant installed to correct. Did this kit change the overall volume to fill the T/C?

 

Thanks,

Kerry

[NicoMega]

I'm slightly confused and getting somewhat frustrated. I bought my Denali earlier this year, and it was running great with no problems. I was trying to diagnose a vibration/noise after awhile, and the local GMC dealer said it was the T/C and it needed rebuilt. I got the T/C rebuilt by a GM tech friend with all new bearings, seals, and chain. Since that time, I've been trying to figure out why I continue to have a T/C leak.

 

When I reinstalled the T/C, I filled it with just over two quarts of Mobil 1 ATF. The T/C began leaking after the first drive as I could smell the ATF and the leak was present on the underside. I thought I had just overfilled it, so I checked the level daily for two weeks to see how much it dropped off. it finally stopped leaking when I dropped from around 1600mL to around 1125mL as drained from the T/C. I refilled it again with new M1 ATF, and it again started leaking until around 1125mL give or take.

 

The yoke doesn't have a groove or wear marks, and the seal continues to look brand new when checked. It only leaks when driven so could pressure be building up in the T/C pushing ATF out?

 

Any advice on this issue or possible causes? My T/C did not have the weep hole from the pump rub, and I had the kit from Merchant installed to correct. Did this kit change the overall volume to fill the T/C?

 

Thanks,

Kerry

 

 

Have you considered transmission issues?? Or I guess I should ask if the trans is original??? There could be pressure building up in the T-Case from a malfunctioning rear shaft seal in the trans and it is pushing fluid into the T-case. I have seen this happen. Also it could be the cheap gaskets that GM uses in there rebuild kits.

 

Also, I am pretty sure ATF is incorrect to be using in your T-Case especially if it's All-time All-Wheel drive. What you need to be using is that Blue T-Case fluid only found at the dealership. It's pricey but meant for this applications viscosity(again especially if it All-time All-whell drive) requirements and you only need one quart anyway.

 

Good luck

 

Nico

 

P.S. These are just my two cents and I am in no way a reliable source. Just trying to pass on what knowledge I have through experience.

[tayldss]

I'd had my drivetrain serviced earlier this week and now my transfer case is leaking too - I'm back sitting at the stealership right now. Rear output shaft seal is puking fluid all over underneath. They're telling me it could just be the seal or the yoke or bearings are bad.

"With such high mileage on an older vehicle are you sure you want to fix it or get a new vehicle?" I hate that lazy sales-pitch.

I'm ONLY at 198,000mi on an '04 and YES I am keeping the truck and want it fixed. I'm having a new seal installed now. Hope it stops the leak, my DD is on the fritz.

 

I see you've already had your T/c rebuilt and your yoke/seals look good...and you're in a newer model truck... How much do new transfer cases cost if we can't figure out our leaks? (No other issues)

 

I had a wicked vibration and narrowed it to a bad u-joint. Just my 2cents.

Sorry I'm more questions and ranting than help,Goodluck!

[tayldss]

...seal didn't fix it for me. FML

[ChevroletCustomerService]

I'd had my drivetrain serviced earlier this week and now my transfer case is leaking too - I'm back sitting at the stealership right now. Rear output shaft seal is puking fluid all over underneath. They're telling me it could just be the seal or the yoke or bearings are bad.

"With such high mileage on an older vehicle are you sure you want to fix it or get a new vehicle?" I hate that lazy sales-pitch.

I'm ONLY at 198,000mi on an '04 and YES I am keeping the truck and want it fixed. I'm having a new seal installed now. Hope it stops the leak, my DD is on the fritz.

 

I see you've already had your T/c rebuilt and your yoke/seals look good...and you're in a newer model truck... How much do new transfer cases cost if we can't figure out our leaks? (No other issues)

 

I had a wicked vibration and narrowed it to a bad u-joint. Just my 2cents.

Sorry I'm more questions and ranting than help,Goodluck!

 

Keep me posted on your progress. Feel free to contact me if you need additional assistance. Thank you.

 

Tricia, Chevrolet Customer Service.

[analyte]

Have you considered transmission issues?? Or I guess I should ask if the trans is original??? There could be pressure building up in the T-Case from a malfunctioning rear shaft seal in the trans and it is pushing fluid into the T-case. I have seen this happen. Also it could be the cheap gaskets that GM uses in there rebuild kits.

 

Also, I am pretty sure ATF is incorrect to be using in your T-Case especially if it's All-time All-Wheel drive. What you need to be using is that Blue T-Case fluid only found at the dealership. It's pricey but meant for this applications viscosity(again especially if it All-time All-whell drive) requirements and you only need one quart anyway.

 

Good luck

 

Nico

 

P.S. These are just my two cents and I am in no way a reliable source. Just trying to pass on what knowledge I have through experience.

 

I used a rebuild kit from Monster transmission rather than a GM kit, and the parts appears to be of good quality. I also got some feedback from other sources that the kits were good to use.

 

That said, I also switched to the Autotrac II based on a dealer recommendation, but my true reason for asking was to switch to the blue fluid to verify the trans wasn't a contributor. I'm comfortable after watching it over the past few days that it's not a trans problem. I called my friend to verify, and he confirmed all the internal bearings and chain was swapped along with the Merchant pump rub kit. The seal didn't look damaged, but changing to the blue fluid made it easier to verify the source.

 

 

I guess my only course of action left is to swap on a new yoke to see if the that helps even though I don't see a wear pattern or groove. If it still leaks, I'll swap on a new output seal. My last option will be to pull the T/C again and have him pull it apart for inspection. The stains on my driveway are starting to drive me nuts.

 

Thanks for all the suggestions so far.

 

Kerry

[tayldss]

Keep me posted on your progress. Feel free to contact me if you need additional assistance. Thank you.

 

Tricia, Chevrolet Customer Service.

 

Well, I still have a pretty bad leak from the rear output shaft seal. After a 4 mile drive it's about empty and has sprayed all down the underside of the truck. My yoke looked ok but that was going to be next in the troubleshooting... then if that didn't work they wanted to pull the T/C and rebuild it $$$$. I couldn't justify another lump in labor costs after the seal didn't fix it.

 

Analyte - keep me posted if your yoke does the trick... I might be more willing to jump at it then.

 

My transmission is just as old - I'd be tempted to try and find both new/built transmission and transfer case and be done with it. I don't plan on getting rid of the truck for a very long time. Any recommendations?

 

For now, I elected the cheaper route - bag of oil dry for the puddles and a few quarts of fluid to top it off once a week or so.

 

The fluid leaking after dealer service is sorta clear, almost like new motor oil. I bought GM Part #88861800 Manual Transmission and Transfer Case fluid from the same dealership's parts department that same day using my VIN and that fluid is red. My question now is, am I using the right fluid? Or could the dealership have used the wrong fluid?

Edited November 28, 2012 by tayldss (see edit history)

[Downeast Johnny]

Well, I still have a pretty bad leak from the rear output shaft seal. After a 4 mile drive it's about empty and has sprayed all down the underside of the truck. My yoke looked ok but that was going to be next in the troubleshooting... then if that didn't work they wanted to pull the T/C and rebuild it $$$$. I couldn't justify another lump in labor costs after the seal didn't fix it.

 

Analyte - keep me posted if your yoke does the trick... I might be more willing to jump at it then.

 

My transmission is just as old - I'd be tempted to try and find both new/built transmission and transfer case and be done with it. I don't plan on getting rid of the truck for a very long time. Any recommendations?

 

For now, I elected the cheaper route - bag of oil dry for the puddles and a few quarts of fluid to top it off once a week or so.

 

The fluid leaking after dealer service is sorta clear, almost like new motor oil. I bought GM Part #88861800 Manual Transmission and Transfer Case fluid from the same dealership's parts department that same day using my VIN and that fluid is red. My question now is, am I using the right fluid? Or could the dealership have used the wrong fluid?

 

TayldSS, Your post reminded me of this post;

 

http://www.silverado...+transfer +case

 

Thought that I would link it so that you can check it out.

 

Hope it helps you some, and good luck with your trouble.

 

Edit to add,

 

I should have included this link to my search of the forums for "Leaking transfer case".

 

Plenty here to check out.

 

http://www.silveradoss.com/forums/index.php?app=core&module=search&do=search&fromMainBar=1

Edited November 28, 2012 by Downeast Johnny (see edit history)

[tayldss]

Thanks Johnny!

[Downeast Johnny]

Thanks Johnny!

 

Welcome.

 

Good luck and let us know what you find.