72 blazer shifting into 4 wheel drive - The 1947 - Present Chevrolet & GMC Truck Message Board Network

ocotillo rat · 10-16-2006, 01:33 PM

I dont have the instruction manual for my 72 Blazer on the proper way to shift into 4 wheel drive. I would like to know the proper way to do this as I have tried on my own yesterday and putting it back into 2 wheel drive was difficult at best and a lot of grinding. Please any info on the proper way to do this is greatly appreciated.

thanks

72 CustomCamper · 10-17-2006, 12:16 AM

Automatic or standard trans?

ocotillo rat · 10-17-2006, 11:40 AM

It is automatic transmission.

some questions I have. Can you unlock the hubs freely by hand or are they hard to unlock and need a pair of pliers to turn them?

Do you have to back up the truck for 20 feet and then unlock the hubs?

You get the picture, I need some info before I put this thing in 4 wheel drive again so I dont damage the 4 wheel drive .

Is is ok to unlock the hubs and drive in 2 wheel drive and when you need 4 wheel drive engagement, shift into 4 low? at low speed.

I need some feedback, step by step 4 wheel drive engagement and back to 2 wheel drive. Igintion off or on, park or neutral, vehicle moving or still.

The picture shows the lock able hub.

Thanks again

**CUSTOM/10** · 10-17-2006, 12:46 PM

Your Blazer should have a NP205 Transfer case in it. It,s an all gear T/C and can be tuff to get in & out of 4wd. It is not a shift on the fly T/C. You should be stopped to shift it. Sometimes you may have to put the truck in drive and rock-it a little while putting preasure on the t/c level to get it to pop out of 4wd. If you go to far and put the t/c into nuetral, shut the truck off before trying to put it back into gear. You do not have to back up to disengage the hubs. Once you get the t/c into 2wd the hubs should turn more freely. You must be stopped to shift into 4wd Lo. Once you get used to shifting it in & out of 4wd, you'll find you can shift in & out of 4wd ( 4wd Hi only ) while driving slow as long as your hubs are locked in. This keeps all the gears and drive shafts turning at the same spead and it can be done carefully. Do not try it if your hubs are not locked in. You'll grind the gears. If you have any grinding while trying to shift in or out of 4wd shut the truck off then shift it.

Hope this helps.
Gary

1969K10 · 10-18-2006, 06:09 PM

I got a T-221 X-fer instead, but if it's that difficult to shift, you probably need to look at the stuff related to shifting it. Mine was a PITA to shift until I rebuilt the whole thing. I found lots of slop in the shifter, and the bracket was loose. When it went back together, it shifts like glass now! I can go into 4-HI at just about any speed, and unfortunatly, I have done it at about 65... Occasionally, it will be almost impossible to get out of 4-HI, when this happens, I've found that backing up a little bit (less than 2 feet) seams to make it easier.
When going into 4-LO, stop completely to shift.

10-16-2006, 01:33 PM	#1
ocotillo rat Registered User Join Date: Sep 2006 Location: San diego Posts: 36	72 blazer shifting into 4 wheel drive I dont have the instruction manual for my 72 Blazer on the proper way to shift into 4 wheel drive. I would like to know the proper way to do this as I have tried on my own yesterday and putting it back into 2 wheel drive was difficult at best and a lot of grinding. Please any info on the proper way to do this is greatly appreciated. thanks __________________ robert _____________________ 1972 Blazer, automatic transmision. FB385 fast burn 385hp Edl 1407 carb 750cfm 3.73 gears 4" lift

10-17-2006, 12:16 AM	#2
72 CustomCamper huh ??? Join Date: Nov 2002 Location: Fredericksburg,Va. Posts: 3,369	Re: 72 blazer shifting into 4 wheel drive Automatic or standard trans? __________________ 90 Blazer Silverado 350w/ 700R4 and 32" Kelly's "I am a bomb technician. If you see me running try to keep up!"

10-17-2006, 11:40 AM	#3
ocotillo rat Registered User Join Date: Sep 2006 Location: San diego Posts: 36	Re: 72 blazer shifting into 4 wheel drive It is automatic transmission. some questions I have. Can you unlock the hubs freely by hand or are they hard to unlock and need a pair of pliers to turn them? Do you have to back up the truck for 20 feet and then unlock the hubs? You get the picture, I need some info before I put this thing in 4 wheel drive again so I dont damage the 4 wheel drive . Is is ok to unlock the hubs and drive in 2 wheel drive and when you need 4 wheel drive engagement, shift into 4 low? at low speed. I need some feedback, step by step 4 wheel drive engagement and back to 2 wheel drive. Igintion off or on, park or neutral, vehicle moving or still. The picture shows the lock able hub. Thanks again Attached Images __________________ robert _____________________ 1972 Blazer, automatic transmision. FB385 fast burn 385hp Edl 1407 carb 750cfm 3.73 gears 4" lift

10-17-2006, 12:46 PM	#4
CUSTOM/10 Senior Member Join Date: May 2003 Location: Sandown, NH Posts: 2,801	Re: 72 blazer shifting into 4 wheel drive Your Blazer should have a NP205 Transfer case in it. It,s an all gear T/C and can be tuff to get in & out of 4wd. It is not a shift on the fly T/C. You should be stopped to shift it. Sometimes you may have to put the truck in drive and rock-it a little while putting preasure on the t/c level to get it to pop out of 4wd. If you go to far and put the t/c into nuetral, shut the truck off before trying to put it back into gear. You do not have to back up to disengage the hubs. Once you get the t/c into 2wd the hubs should turn more freely. You must be stopped to shift into 4wd Lo. Once you get used to shifting it in & out of 4wd, you'll find you can shift in & out of 4wd ( 4wd Hi only ) while driving slow as long as your hubs are locked in. This keeps all the gears and drive shafts turning at the same spead and it can be done carefully. Do not try it if your hubs are not locked in. You'll grind the gears. If you have any grinding while trying to shift in or out of 4wd shut the truck off then shift it. Hope this helps. Gary __________________ Gary 72 SWB 4x4 My 72 SWB Build http://67-72chevytrucks.com/vboard/s...d.php?t=259859 Last edited by CUSTOM/10; 10-17-2006 at 12:51 PM.

10-18-2006, 06:09 PM	#5
1969K10 Senior Member Join Date: Jul 2004 Location: Clarks Hill, Indiana Posts: 733	Re: 72 blazer shifting into 4 wheel drive I got a T-221 X-fer instead, but if it's that difficult to shift, you probably need to look at the stuff related to shifting it. Mine was a PITA to shift until I rebuilt the whole thing. I found lots of slop in the shifter, and the bracket was loose. When it went back together, it shifts like glass now! I can go into 4-HI at just about any speed, and unfortunatly, I have done it at about 65... Occasionally, it will be almost impossible to get out of 4-HI, when this happens, I've found that backing up a little bit (less than 2 feet) seams to make it easier. When going into 4-LO, stop completely to shift.



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