93 z71 transfer case problem/noise - Pirate4x4.Com : 4x4 and Off-Road Forum

azarath · 03-08-2003, 01:03 AM

I have a 93 z71 w/ 4x4 auto tranny and Im having a strange problem. While driving either slow or fast I get a random "Bang" noise comming from the transfer case area, (more like someone hitting it with a sledge hammer) It can happen at 10 mph or 70. When it does happen I get a slight jolt of resistance as if the front hubs are trying to lock, I cant say for sure but thats what it feels like? After the noise occurs I'll put it in 4X4 and drive it for awhile and no banging noise happens? after its put back into 2x4 its fine for awhile, then driving over speed bumps or railroad tracks seem to set it off again......... I know for sure its not the ring clip on the input shaft due to a shop looking at it.

I just took out the front driveline and drove iot for awhile and the problem is still there, I guess the next step it to remove the 4x4 swith going into the transfer case?

Anyone had or heard of this problem?

Thanks for any help on this.

Rob

PJohnson · 03-12-2003, 11:12 AM

Nobody has experienced this?

azarath · 03-12-2003, 11:54 AM

Im not sure what the problem here is, 30 something people have read this post (all owning chevys) and nobody has ever heard of this problem before?

Its ok, I may be a "newbie" but I figured out the problem and solution on my own.

lt1yj · 03-12-2003, 08:41 PM

If you do a search you'll find this question has been asked before.

The problem is the little plastic pieces on the mode shaft forks are worn off or have fallen off. That lets the mode shaft slip inside the sun gear. If you keep running it like that it will round over the ends of the engagement splines and wear grooves in the mode shaft fork.

Edit: And it will continue to get worse until the case pops in and out of gear continuously. end edit

The only way to fix it is to disassemble the case and replace the plastic pieces. Check the mode shaft, shift fork, and sun gear very carefully for damage. Reuse if they aren't damaged. Replace if the splines are damaged or if there is wear in the shift fork.

PJohnson · 03-13-2003, 09:20 AM

lt1yj - Thanks for replying. We've been pretty stumped by this problem.

FWIW - I did try a search, but couldn't define the keywords narrowly enough to get a reasonable number of results.

Phil

03-08-2003, 01:03 AM	#1 (permalink)
azarath Registered User Join Date: Mar 2003 Member # 17676 Location: Scotts valley, CA Posts: 2	93 z71 transfer case problem/noise I have a 93 z71 w/ 4x4 auto tranny and Im having a strange problem. While driving either slow or fast I get a random "Bang" noise comming from the transfer case area, (more like someone hitting it with a sledge hammer) It can happen at 10 mph or 70. When it does happen I get a slight jolt of resistance as if the front hubs are trying to lock, I cant say for sure but thats what it feels like? After the noise occurs I'll put it in 4X4 and drive it for awhile and no banging noise happens? after its put back into 2x4 its fine for awhile, then driving over speed bumps or railroad tracks seem to set it off again......... I know for sure its not the ring clip on the input shaft due to a shop looking at it. I just took out the front driveline and drove iot for awhile and the problem is still there, I guess the next step it to remove the 4x4 swith going into the transfer case? Anyone had or heard of this problem? Thanks for any help on this. Rob Last edited by azarath; 03-10-2003 at 07:31 AM.

03-12-2003, 11:12 AM	#2 (permalink)
PJohnson Registered User Join Date: Feb 2000 Member # 263 Location: Gilroy, CA Posts: 1,325	bump Nobody has experienced this?

03-12-2003, 11:54 AM	#3 (permalink)
azarath Registered User Join Date: Mar 2003 Member # 17676 Location: Scotts valley, CA Posts: 2	No help at all? Im not sure what the problem here is, 30 something people have read this post (all owning chevys) and nobody has ever heard of this problem before? Its ok, I may be a "newbie" but I figured out the problem and solution on my own.

03-12-2003, 08:41 PM	#4 (permalink)
lt1yj Registered User Join Date: Jan 2002 Member # 9467 Location: Michigan Posts: 1,620	If you do a search you'll find this question has been asked before. The problem is the little plastic pieces on the mode shaft forks are worn off or have fallen off. That lets the mode shaft slip inside the sun gear. If you keep running it like that it will round over the ends of the engagement splines and wear grooves in the mode shaft fork. Edit: And it will continue to get worse until the case pops in and out of gear continuously. end edit The only way to fix it is to disassemble the case and replace the plastic pieces. Check the mode shaft, shift fork, and sun gear very carefully for damage. Reuse if they aren't damaged. Replace if the splines are damaged or if there is wear in the shift fork. Last edited by lt1yj; 03-12-2003 at 08:43 PM.

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

03-13-2003, 09:20 AM	#5 (permalink)
PJohnson Registered User Join Date: Feb 2000 Member # 263 Location: Gilroy, CA Posts: 1,325	lt1yj - Thanks for replying. We've been pretty stumped by this problem. FWIW - I did try a search, but couldn't define the keywords narrowly enough to get a reasonable number of results. Phil