Transfer case whine

[zmusclow]

I have a 2002 Tahoe and the transfer case whines while in 2high, it gets quieter while under a load and goes away when shifted into 4high. Seems like the chain could be stretching and whining while not under a load. I am capable of rebuilding the transfer case myself, but there are so many rebuild kits that very in parts and price. Please give me your insight! Thank you

 

[Bill 1960]

I’d call precision transmission in Texas and see if they will sell you what they use. They have a popular YouTube channel and are well respected.

Rebuild kits are not very costly but there’s so much chyna crap floating around in the marketplace it’s hard to know what is safe to buy these days.

 

[Bill 1960]

Afterthought- be leery of noises in the driveline, they can telegraph through the shafts and appear in places other than where they originated.

 

[PNWYukon]

I have a 2002 Tahoe and the transfer case whines while in 2high, it gets quieter while under a load and goes away when shifted into 4high. Seems like the chain could be stretching and whining while not under a load. I am capable of rebuilding the transfer case myself, but there are so many rebuild kits that very in parts and price. Please give me your insight! Thank you

What is the transfer case ID? NPxxx?

Have you ever changed the fluid in it?

Does yours have the Auto4wd button? That adds to the complexity of the internals.

Many times the oil pump pick up tube gets clogged with silicone or debris causing issues, but you can't know without opening it up or a get lighted borescope.

NP246 Transfer Case Master Rebuild Kit (NP246-M)

This NP246 transfer case rebuild kit has everything you need to restore your early- to mid-2000s Chevy 1500, Tahoe or Suburban 4x4 transfer case, including bearings, seals, a chain and output side case half.

www.allstategear.com

Transfer Case NP246 Rebuild Kits, parts and drawing - drivetrain.com

NP246 Transfer Cases Rebuild Kits and Parts. Free diagnostic troubleshooting help including illustrated parts drawing!

www.drivetrain.com

 

[rockola1971]

Unlikely the chain is whining. More likely its a bearing whining. You checked the fluid level in the case? Have a small pinhole on passenger side of Tcase half way up just forward of output shaft? (The pump did it).

 

[zmusclow]

What is the transfer case ID? NPxxx?

Have you ever changed the fluid in it?

Does yours have the Auto4wd button? That adds to the complexity of the internals.

Many times the oil pump pick up tube gets clogged with silicone or debris causing issues, but you can't know without opening it up or a get lighted borescope.

NP246 Transfer Case Master Rebuild Kit (NP246-M)

This NP246 transfer case rebuild kit has everything you need to restore your early- to mid-2000s Chevy 1500, Tahoe or Suburban 4x4 transfer case, including bearings, seals, a chain and output side case half.

www.allstategear.com

Transfer Case NP246 Rebuild Kits, parts and drawing - drivetrain.com

NP246 Transfer Cases Rebuild Kits and Parts. Free diagnostic troubleshooting help including illustrated parts drawing!

www.drivetrain.com

I will have to look for the model number on the transfer case. It does have the auto 4wd button though.

 

[zmusclow]

Unlikely the chain is whining. More likely its a bearing whining. You checked the fluid level in the case? Have a small pinhole on passenger side of Tcase half way up just forward of output shaft? (The pump did it).

I bought this Tahoe as a mess. Rebuilt rear end and got rid of that whine, then replaced front end to get rid of that whine. I changed the T-case fluid when I bought the truck and haven’t seen any leaks at all.

 

[zmusclow]

Afterthought- be leery of noises in the driveline, they can telegraph through the shafts and appear in places other than where they originated.

I agree! The only reason I believe it to be the T-Case is because the noise goes away while I’m 4wd and resumes after back in 2wd

 

[Fless]

You probably have the NP246 TC and, if so, hopefully the fluid you used was the Auto Trac II blue fluid.

 

[rockola1971]

I bought this Tahoe as a mess. Rebuilt rear end and got rid of that whine, then replaced front end to get rid of that whine. I changed the T-case fluid when I bought the truck and haven’t seen any leaks at all.

When you changed the Tcase fluid how much did you get out of it? Did you check its level before draining it to make sure it hadnt been ran low? It is quite possible that you have a bearing inside the Tcase on its way out. If you plan on keeping the Tahoe around I would just drop the Tcase and do a quick rebuild. They are stupid easy to rebuild. Theres tons of videos on youtube. My 03's have the NP246E model Tcase with the Autotrac (Auto 4wd) which means theres some clutches in the Tcase. Rebuild kits expect to pay around $350 or less if I remember correctly for standard rebuild parts (Seals and Bearing kit, Chain, Clutches if you have the Auto 4wd, fluid, Internal/External snapring pliers with long reach). But the pump rub fix plate for around $25. If yours is already rubbed through and many are then expect to buy a replacement rear half case. Inspect for the rub hole in yours. Tons of youtube videos on this also.