Anyone know whats wrong with my transfer case??? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

*FUNMUDDER* · 10-25-2005, 07:00 PM

I just got a 68 GMC 2500 4x4. When we bought it, the guy told us it trys to pop out of gear (in the tranfer case) when backing up, and it succeeds. Anyone know what the problem is? Linkage or inside it? From what they told me in the other thread, it is a Rockwell 221c. It's big and funny-looking if that helps any

.

*FUNMUDDER* · 10-25-2005, 09:05 PM

Anyone????

nu2-72 · 10-25-2005, 09:15 PM

I am not really sure what you mean when you talk of the transfer case and reverse. Is this a manual transmission or auto, does the trans. pop out of reverse or the transfer stop moving with the tranny in reverse? Remove the linkage and place in reverse. Does it pop out then? It's inside. If it stays in,then it's linkage. You may even look to see how far it travels with linkage attached and how far detached. This would tell you how for out of adjustment it is or give you a starting point. Not knowing if the tranny selector is popping out or the 4x4 high/low shifter,this is about all I can suggest here.
If it is a manual tranny and popping out of reverse it may be the tranny and not the transfer case.
Not enough info to help much. Sorry.

al's71gmc · 10-25-2005, 09:50 PM

Check the tranny mounts. If one is broken or lose, maybe the torque in reverse is moving the linkage enuf to disengage. Could also be a bearing going out on the output or input shaft. I had that happen on a transmission before and it would kick out of 1st and 3rd gear. Hope this helps.
Al

4x4Poet · 10-26-2005, 01:27 AM

Great advice, already. I'll take the obvious.

Remove the transfer case shifter boot so you can see if the lever is hitting the hump opening when the engine torques in reverse. If the lever is real close, consider whether the installed boot is hit while the tranny's in reverse.

Blazer1970 · 10-26-2005, 07:10 AM

A broken motor mount could do this also, not just the tranny mounts.

toroflow · 10-26-2005, 04:28 PM

I was grinding down a hill the other day in granny gear and low range in my divorced T-221 ('64 Sub 4x4) when it popped out of low range and into neutral!!! What a scare!!! I don't know what it could be, but I now just hold the shifter in low when descending any big hills to avoid another scare!!

*FUNMUDDER* · 10-26-2005, 09:42 PM

Its motor mounts are all good. WHILE backing up, the transfer case pops out of gear in the in 2wd and 4wd HI, but not 4LO

, the transmission is fine, and very, very tight.. I'll check the tranny mounts, but I'm starting to think it is the linkage itself. The transfer case shifter is extremely sloppy, too.

1969K10 · 10-27-2005, 09:13 AM

I'm just guessing here, but when i rebuilt my Rockwell, there are springs that hold balls in detents in the shafts that move in and out with the shifter. I'd guess that you've broken the spring that holds the high range shaft in the correct position.

checked out your pics, nice score!!! The oiling holes in the bed intruige me, what a concept!

*FUNMUDDER* · 10-27-2005, 06:08 PM

Thanks for the info. Where can I find parts for a Rockwell transfer? Or would I be better off to start looking for a NP205 to put in?

4x4Poet · 10-28-2005, 02:08 AM

http://www.drivetrain.com/transfercasesparts.html

Expensive. Other sites exist.

1969 GMC · 10-28-2005, 03:59 PM

Quote:

Originally Posted by FUNMUDDER

Thanks for the info. Where can I find parts for a Rockwell transfer? Or would I be better off to start looking for a NP205 to put in?

If you go to a NP205, you have to move the crossmember back a little bit (1.5" or 2", can't remember), re-do your driveshafts accordingly, and get a 10 spline NP205 from behind a sm465, as well as the adapter and sleeve. If you have a divorced Rockwell (possible I guess) it will make it easier.

1969K10 · 11-02-2005, 04:13 PM

I believe I went thru Drivetrain. For some exploded views, check out http://www.zianet.com/desertskies/Rockwell%20T-221.pdf

skiscott00 · 11-16-2005, 02:32 PM

I have a divorced t-221 unit for sale and I also have enough parts to rebuild one as well. Mel 916-670-7395

skiscott00 · 11-16-2005, 11:43 PM

I had mine do this about 20 years ago and it was the idler shaft. Once I had it replaced along with the springs in the top plate, it took care of the problem.

*FUNMUDDER* · 11-17-2005, 09:52 PM

Where did you get the parts for it????? Cali is too far away for me, and I dont like the thoughts of shipping stuff. Are idler shafts a hefty price, or no?

10-25-2005, 07:00 PM	#1
FUNMUDDER Account Suspended Join Date: Jun 2005 Location: Maine Posts: 427	Anyone know whats wrong with my transfer case??? I just got a 68 GMC 2500 4x4. When we bought it, the guy told us it trys to pop out of gear (in the tranfer case) when backing up, and it succeeds. Anyone know what the problem is? Linkage or inside it? From what they told me in the other thread, it is a Rockwell 221c. It's big and funny-looking if that helps any .

10-25-2005, 09:05 PM	#2
FUNMUDDER Account Suspended Join Date: Jun 2005 Location: Maine Posts: 427	Re: Anyone know whats wrong with my transfer case??? Anyone????

10-25-2005, 09:15 PM	#3
nu2-72 Senior Member Join Date: Apr 2001 Location: Amazonia, Mo. USA Posts: 2,821	Re: Anyone know whats wrong with my transfer case??? I am not really sure what you mean when you talk of the transfer case and reverse. Is this a manual transmission or auto, does the trans. pop out of reverse or the transfer stop moving with the tranny in reverse? Remove the linkage and place in reverse. Does it pop out then? It's inside. If it stays in,then it's linkage. You may even look to see how far it travels with linkage attached and how far detached. This would tell you how for out of adjustment it is or give you a starting point. Not knowing if the tranny selector is popping out or the 4x4 high/low shifter,this is about all I can suggest here. If it is a manual tranny and popping out of reverse it may be the tranny and not the transfer case. Not enough info to help much. Sorry. __________________ 72 3/4 4x4 350 4spd 72 3/4 4x4 350 auto 2004 Duramax Silverado 4x4 2006 Duramax Crew cab 4x4 2010 Harley Ultra Limited 2011 Harley Street Glide

10-25-2005, 09:50 PM	#4
al's71gmc 4 eyed fever Join Date: Jul 2005 Location: Eureka, Nevada Posts: 500	Re: Anyone know whats wrong with my transfer case??? Check the tranny mounts. If one is broken or lose, maybe the torque in reverse is moving the linkage enuf to disengage. Could also be a bearing going out on the output or input shaft. I had that happen on a transmission before and it would kick out of 1st and 3rd gear. Hope this helps. Al __________________ 1971 GMC 2500 4x4 1972 GMC Sierra Grande 1/2 t 4x4-#1 son's truck. Recently completed resto. 4 YO daughter," Daddy, I like your truck better than Mom's." (2000 F350-ranch truck) Smart kid!!

10-26-2005, 01:27 AM	#5
4x4Poet Registered User Join Date: Nov 2004 Location: "Under Montana skies." Posts: 1,836	Re: Anyone know whats wrong with my transfer case??? Great advice, already. I'll take the obvious. Remove the transfer case shifter boot so you can see if the lever is hitting the hump opening when the engine torques in reverse. If the lever is real close, consider whether the installed boot is hit while the tranny's in reverse. __________________ '71 GMC K20 Suburban, '71 GMC K10 Suburban, '72 Chevy C10 CST Suburban, '72 Chevy K20 clunker pickup.

10-26-2005, 07:10 AM	#6
Blazer1970 Registered User Join Date: Dec 1999 Location: Old Mission, MI, USA Posts: 2,507	Re: Anyone know whats wrong with my transfer case??? A broken motor mount could do this also, not just the tranny mounts. __________________ Tim

10-26-2005, 04:28 PM	#7
toroflow Registered User Join Date: May 2005 Location: Anaheim, CA Posts: 103	Re: Anyone know whats wrong with my transfer case??? I was grinding down a hill the other day in granny gear and low range in my divorced T-221 ('64 Sub 4x4) when it popped out of low range and into neutral!!! What a scare!!! I don't know what it could be, but I now just hold the shifter in low when descending any big hills to avoid another scare!! __________________ Ken '60 GMC 3/4T 4x4 '60 GMC Suburban 4x4 '64 GMC Suburban 4x4

10-26-2005, 09:42 PM	#8
FUNMUDDER Account Suspended Join Date: Jun 2005 Location: Maine Posts: 427	Re: Anyone know whats wrong with my transfer case??? Its motor mounts are all good. WHILE backing up, the transfer case pops out of gear in the in 2wd and 4wd HI, but not 4LO , the transmission is fine, and very, very tight.. I'll check the tranny mounts, but I'm starting to think it is the linkage itself. The transfer case shifter is extremely sloppy, too. Last edited by FUNMUDDER; 10-26-2005 at 09:45 PM.

10-27-2005, 09:13 AM	#9
1969K10 Senior Member Join Date: Jul 2004 Location: Clarks Hill, Indiana Posts: 733	Re: Anyone know whats wrong with my transfer case??? I'm just guessing here, but when i rebuilt my Rockwell, there are springs that hold balls in detents in the shafts that move in and out with the shifter. I'd guess that you've broken the spring that holds the high range shaft in the correct position. checked out your pics, nice score!!! The oiling holes in the bed intruige me, what a concept!

10-27-2005, 06:08 PM	#10
FUNMUDDER Account Suspended Join Date: Jun 2005 Location: Maine Posts: 427	Re: Anyone know whats wrong with my transfer case??? Thanks for the info. Where can I find parts for a Rockwell transfer? Or would I be better off to start looking for a NP205 to put in?

10-28-2005, 02:08 AM	#11
4x4Poet Registered User Join Date: Nov 2004 Location: "Under Montana skies." Posts: 1,836	Re: Anyone know whats wrong with my transfer case??? http://www.drivetrain.com/transfercasesparts.html Expensive. Other sites exist. __________________ '71 GMC K20 Suburban, '71 GMC K10 Suburban, '72 Chevy C10 CST Suburban, '72 Chevy K20 clunker pickup.

11-02-2005, 04:13 PM	#13
1969K10 Senior Member Join Date: Jul 2004 Location: Clarks Hill, Indiana Posts: 733	Re: Anyone know whats wrong with my transfer case??? I believe I went thru Drivetrain. For some exploded views, check out http://www.zianet.com/desertskies/Rockwell%20T-221.pdf

11-16-2005, 02:32 PM	#14
skiscott00 Registered User Join Date: Nov 2005 Location: california Posts: 25	Re: Anyone know whats wrong with my transfer case??? I have a divorced t-221 unit for sale and I also have enough parts to rebuild one as well. Mel 916-670-7395 Last edited by skiscott00; 11-16-2005 at 11:44 PM.

11-16-2005, 11:43 PM	#15
skiscott00 Registered User Join Date: Nov 2005 Location: california Posts: 25	Re: Anyone know whats wrong with my transfer case??? I had mine do this about 20 years ago and it was the idler shaft. Once I had it replaced along with the springs in the top plate, it took care of the problem.

11-17-2005, 09:52 PM	#16
FUNMUDDER Account Suspended Join Date: Jun 2005 Location: Maine Posts: 427	Re: Anyone know whats wrong with my transfer case??? Where did you get the parts for it????? Cali is too far away for me, and I dont like the thoughts of shipping stuff. Are idler shafts a hefty price, or no?



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