BW4485 (NR3) awd Transfer Case Rebuild?

[donjetman]

07 awd Denali w/193k miles.
No leaks but I think the chain is stretched.
Has anybody rebuilt their Borg Warner BW4485 (rpo code NR3) awd transfer case?
and did it reduce the Clunk?
I've watched some videos and the job looks easy enough and parts cost is about $300.
TIA

 

[Geotrash]

07 awd Denali w/193k miles.
No leaks but I think the chain is stretched.
Has anybody rebuilt their Borg Warner BW4485 (rpo code NR3) awd transfer case?
and did it reduce the Clunk?
I've watched some videos and the job looks easy enough and parts cost is about $300.
TIA

Following. I'm in the same boat with my '07 and for now I'm planning to just continue running it, but the clunk is annoying and I've done both the motor and diff mounts already. Rock Auto sells the chain and seals, but the planetary gears inside look intimidating to work with, and I'd like to know what else I should replace while I'm in there.

I took this video 20K miles ago and it certainly hasn't gotten any tighter. My 2012 doesn't have this play but I think it's also a different AWD transfer case.

 

[petethepug]

ChiefM did in his 07 Esky over on the CF forum, along with almost every single component on the truck. Sift through the pages and see what he ran into. I searched transfer case under his user name.

"ChiefM, post:
Going back strictly stock.
I didn't think of getting a new flex plate, I think I'm going to get a new Harmonic balancer and motor mounts too. I already have a new radiator and a new chain for the transfer case. Thinking of a new power steering pump, that's really the only thing on the engine I have not changed out.

This should get her to where I only have to do routine maintenance. Everything else on the truck is 1 to 3 years old at max.

 

[donjetman]

Here's the transfer case parts I'd replace in mine:
Chain = $160:
https://www.transmissionpartsdistri...-fits-03-hummer-07-chevy-gmc-cadillac-hv-077/

bearings and seals = $102:
https://www.transmissionpartsdistri...calade-denali-yukon-etc-with-nr3-code-bk4485/

 

[Geotrash]

Here's the transfer case parts I'd replace in mine:
Chain = $160:
https://www.transmissionpartsdistri...-fits-03-hummer-07-chevy-gmc-cadillac-hv-077/

bearings and seals = $102:
https://www.transmissionpartsdistri...calade-denali-yukon-etc-with-nr3-code-bk4485/

Have you priced what it would cost to farm out the job? If it's less than $1K, I'll probably see if the local 4x4 shop can do it.

 

[donjetman]

Have you priced what it would cost to farm out the job? If it's less than $1K, I'll probably see if the local 4x4 shop can do it.

No, after watching some utube vids and seeing how easy it is too do, I'd do it myself for sure (I have a 2 post lift).

 

[Geotrash]

No, after watching some utube vids and seeing how easy it is too do, I'd do it myself for sure (I have a 2 post lift).

That's what I was hoping you'd say. I'll live vicariously through your experience and do the same myself, though I only have a lowly horrible freight transmission jack.

 

[petethepug]

The xfer case and diff are one of GM’s unsung, boring components that I love not worrying about.

 

[donjetman]

No, after watching some utube vids and seeing how easy it is too do, I'd do it myself for sure (I have a 2 post lift).

Yeah, like when I did the RMS job, I'll lower the vehicle close to the floor and use my HF lawnmower jack to pull it and install it.
https://www.tahoeyukonforum.com/thr...7-yukon-denali-6-2.108334/page-2#post-1291151

 

[skpyle]

Subscribed and watching this. Sooner or later I will have to replace the chain in the BW 4485 in my Escalade.
Thanks!

 

[HardHead]

Folks, there are some things they don't show on YouTube. I found that the output pilot bushing was terribly loose and full of gunk. It had built up so badly, it had pushed the shaft to one side and rubbed a funny spot on the output shaft.

Also, the drive sprocket bushing was several thousands out, which made a big wobble and the chain a little looser than it should be. I replaced that bushing and wow, not NEARLY as much play, just a tiny bit.

I did learn how to time the 60/40 planetary gear. Pretty simple, but I was tired and turned to YouTube.

Thing is, when I washed it out, I felt more needed to be done. So, brake cleaner in hand I began to wash and spin each set of gear combinations. MAN...lots of bronze dusk was on my towel. SO, I blew it dry, put down a fresh towel and did it again. Just as much bronze as before. Did it a third time, and again, lots of bronze dust. By the fourth time I still had some bronze but now it was an acceptable level. Now...this was done after a good cleaning in the parts washer.

I feel the BW4485 could have benefitted from pilot roller bearings rather than bronze bushings. OR at least require a fluid change every 36K miles.

Thing is, the bushings are cheap. Took a while to find the correct ones.
Oh, there is a bushing behind the slip yoke seal on the rear output.
The toughest one is pressed into the rear output shaft. Used a pilot bearing expandable hammer puller. Took a while, but finally got it. Pressing in, no issues.

Forgot to mention, 214K miles...and I think she was really abused. I also think someone had been in this T case before. The sealant looked layered.

 

[Geotrash]

Folks, there are some things they don't show on YouTube. I found that the output pilot bushing was terribly loose and full of gunk. It had built up so badly, it had pushed the shaft to one side and rubbed a funny spot on the output shaft.

Also, the drive sprocket bushing was several thousands out, which made a big wobble and the chain a little looser than it should be. I replaced that bushing and wow, not NEARLY as much play, just a tiny bit.

I did learn how to time the 60/40 planetary gear. Pretty simple, but I was tired and turned to YouTube.

Thing is, when I washed it out, I felt more needed to be done. So, brake cleaner in hand I began to wash and spin each set of gear combinations. MAN...lots of bronze dusk was on my towel. SO, I blew it dry, put down a fresh towel and did it again. Just as much bronze as before. Did it a third time, and again, lots of bronze dust. By the fourth time I still had some bronze but now it was an acceptable level. Now...this was done after a good cleaning in the parts washer.

I feel the BW4485 could have benefitted from pilot roller bearings rather than bronze bushings. OR at least require a fluid change every 36K miles.

Thing is, the bushings are cheap. Took a while to find the correct ones.
Oh, there is a bushing behind the slip yoke seal on the rear output.
The toughest one is pressed into the rear output shaft. Used a pilot bearing expandable hammer puller. Took a while, but finally got it. Pressing in, no issues.

Forgot to mention, 214K miles...and I think she was really abused. I also think someone had been in this T case before. The sealant looked layered.

Nice job! Thanks for sharing your findings with us. Imma have to dig into mine sometime in the next couple of years, so this is super helpful.