Clunking and stuck in four wheel drive

Tiny
CHRIS FISCHER
  • MEMBER
  • 1999 CHEVROLET BLAZER
  • 4.3L
  • 4WD
  • AUTOMATIC
  • 180,000 MILES
A loud clunking started a couple weeks ago, so we put it in shop. When it got real loud personal shop we noticed it is stuck in four wheel high, replaced actuator, cable, vacuum lines and checked electronic solenoid. We took out four wheel drive driveshaft and drove and no noise is present. When it is is in, a real loud clunking louder when cornering is unbearable. And yes, we replace the whole fry end, ball joints, CV joints, tie rods, Idler arm. Any suggestion? I need help bad and is only transportation!
Wednesday, January 25th, 2017 AT 2:07 PM

10 Replies

Tiny
CHRIS FISCHER
  • MEMBER
  • 6 POSTS
Forgot to mention, we have checked the bearings, and universals in both drive shafts.
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Wednesday, January 25th, 2017 AT 3:25 PM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Was it full of fluid or did you not check? Do what is in picture and get back to us. Although, it may be and sounds like it is an internal problem.
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Wednesday, January 25th, 2017 AT 3:39 PM
Tiny
CHRIS FISCHER
  • MEMBER
  • 6 POSTS
Yes, fluid level good and no burnt smells, however there is a small leak, looks like oil, coming from the front "pumpkin".
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Wednesday, January 25th, 2017 AT 6:18 PM
Tiny
CHRIS FISCHER
  • MEMBER
  • 6 POSTS
Can I take four wheel drive shaft out and drive truck that way or will it cause more damage?
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Wednesday, January 25th, 2017 AT 6:27 PM
Tiny
STEVE W.
  • MECHANIC
  • 12,996 POSTS
No problem pulling the front shaft. The only thing I can think of that would be clunking in the front would be if maybe a couple teeth were damaged on the ring or pinion. Or you have a bad inner joint on one of the front axles. If one was pulled out just enough for the bearing to come off and it went back it it would make a lot of noise.
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Wednesday, January 25th, 2017 AT 9:01 PM
Tiny
STEVE W.
  • MECHANIC
  • 12,996 POSTS
Here is a video with some 4X4 noises, is this what you hear?

https://www.youtube.com/watch?v=xtoL4FjerlM
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-1
Wednesday, January 25th, 2017 AT 9:07 PM
Tiny
CHRIS FISCHER
  • MEMBER
  • 6 POSTS
Yes, that is the clunking. When we take front drive shaft out it still makes the noise, but not that loud. Driving last night with out front drive shaft, we made a couple sharp turns back and forth and heard a pop, then around went away. Still have yet to hear it! I am afraid to put front shaft back in and make the sound return!
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Thursday, January 26th, 2017 AT 4:57 AM
Tiny
CHRIS FISCHER
  • MEMBER
  • 6 POSTS
I have four t-cases from other parts blazers. Question, can I replace my four button auto four wheel Dr with a third button four wheel drive that does not have auto. Do I change the TCCM and/or cables/connectors? Do I have to reprogram the brains together, etc? One of the extra t-cases my have the auto four wheel, but I do not know which one, how can I cross reference these to find the auto t-case out of the other t-cases? Thanks to all who have responded! Hope to return the favor to someone else in need. By the way: the Blazers were scraped, only kept parts, so I do not have the VIN number's.
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Thursday, January 26th, 2017 AT 6:07 AM
Tiny
HMAC300
  • MECHANIC
  • 48,601 POSTS
Go by the ID tag at back of case. It should be same number either a NV233-236 etc. Otherwise you will have problems. See picture.
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Thursday, January 26th, 2017 AT 7:00 AM
Tiny
STEVE W.
  • MECHANIC
  • 12,996 POSTS
Have never looked at swapping the Auto T-case. I think you would need to swap a lot of parts. The T-case, TCCM, wiring harness, switch are all different. Then there are the extra speed sensors and a different ABS system. The BCM is different as well as different ECM programming for the auto controls.

The auto box will be a NV 236.
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Thursday, January 26th, 2017 AT 10:07 AM

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