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4 wheel drive noise problem

16K views 5 replies 4 participants last post by  lin martin 
#1 ·
Hello all,

I have an 03 trailblazer, 100,000 miles. When putting it into 4hi you get a whining noise, this noise is much louder in 4 lo (The best way i can describe this noise is if you take an rc car or something driven by an electric motor and push it along manually,). It doesnt really sound like a bearing or anything like that, also you dont feel anything. After checking fluid levels and such, and the problem not changing, I did some more listening and it seems the noise is coming from the transfer case motor. When the switch is flipped to a 4x4 mode, you can hear the axle motor go into place smoothly, but the differential motor struggles, makes a louder noise than the axle motor and seems to try twice and then it either over rides itself or engage as far as it can i cant really tell although it does go into 4 wheel drive.

Does anyone know how their transfer case motor sounds when it goes in and out of 4 wheel because this sound like its working to hard and binding up a bit.

All the lights on the 4x4 switch work normally, and the service 4x4 light has never been on, also the noise goes away completely in 2wd. I am thinking i will change the transfer case motor just wanted some opinions. Any help appreciated. thank you.
 
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#2 ·
If your fluid level is OK, then you've got it narrowed down correctly. It may still be binding inside the transfer case, though. But swapping that is more work and expense, unless you get a cheap one at a junkyard that includes the encoder motor.

Lots of them on Ebay last I looked. Make sure you get the 7-pin, not the 5-pin.

 
#3 ·
thanks for the reply, yeah i can get a rebuilt for 130 after all is said and done, that seems to be well worth it rather than taking on the transfer case. Fluid levels were good i changed the front diff fluid as it was a little low and didnt know when it was changed last. From your experience does the transfer case motor operation sound similar to the front axle motor engaging, I realise it would be louder but it also sounds more labored and like it tries twice. Thanks again
 
#5 ·
My problem was the transfer case, after not feeling confident in my diagnosis, I brought into a local private shop. He said it was deifinately the transfer case and gave me the options for replacement. New, refurb and junkyard special. I decided to go with the junkyard, found one with 60,000ish miles and had It installed for around 550$ I think. Havent had any problems with that part since and wife heavily used 4 wheel drive in winter. Hope this helps.
 
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