68 K20 won't stay in two wheel drive - The 1947 - Present Chevrolet & GMC Truck Message Board Network

bikefool · 03-07-2015, 06:06 PM

I have a 68 K20 with a 292 and a four speed. It sits in four wheel high and low just fine but if I try to drive it in two wheel, the transfer case pops out of gear. Is this a common thing, easy to fix?

Greasey Harley · 03-07-2015, 06:20 PM

NP205 I assume?
Pretty bulletproof case. That case has 2 rods that slide in and out and there are detents on the rods that keep it "locked" in.
Not much can really go wrong with that system that I can think of, but if it wasn't sliding all the way to the locked in position, it might jump out of 2wd. I would first would look at all the linkage and make sure everything's working properly.

bikefool · 03-07-2015, 06:39 PM

Once the world thaws out I will crawl under it and check which model it is and check the linkage.

71swb4x4 · 03-07-2015, 06:45 PM

I can't help with your problem, but in 68 you should have a Rockwell T221 transfer case. The 205 started in 1969 but I think some auto transmission trucks had T221's in 1969.

hugger6933 · 03-07-2015, 06:46 PM

Welcome to you from Arkansas. There are lots of knowledgeable people here on this board and are willing to help a fellow trucker out. If you need anything in the paint and body area look me up that is where I hang mostly, Jim

Greasey Harley · 03-07-2015, 06:57 PM

Quote:

Originally Posted by 71swb4x4

I can't help with your problem, but in 68 you should have a Rockwell T221 transfer case. The 205 started in 1969 but I think some auto transmission trucks had T221's in 1969.

Huh? I've had two 68's with 205's in them, a K20 with a th350/205 and a k10 with an ms465/205, I always assumed they came that way.

BLT gmc · 03-07-2015, 07:03 PM

GMC used T-221 through most of 69, if not all. It was a mid year change. Chevrolet started with the NP 205 in 69. I agree it sounds like the detents are wore badly. The high hump will have to come off so you can access the top of the case. You do not need to get under the truck to tell the T-221 from the NP 205. T-221 has shifter on the driver side of the 4 spd, The NP 205 shifter is on the passenger side of the 4 spd. Bruce

bikefool · 03-11-2015, 07:23 AM

Good to know. It is definitely on the driver's side so it must be a T-221. I will have to check out the detents.

03-07-2015, 06:06 PM	#1
bikefool Registered User Join Date: Sep 2013 Location: Occum, CT Posts: 5	68 K20 won't stay in two wheel drive I have a 68 K20 with a 292 and a four speed. It sits in four wheel high and low just fine but if I try to drive it in two wheel, the transfer case pops out of gear. Is this a common thing, easy to fix?

03-07-2015, 06:20 PM	#2
Greasey Harley Registered User Join Date: May 2013 Location: Post Falls, ID Posts: 898	Re: 68 K20 won't stay in two wheel drive NP205 I assume? Pretty bulletproof case. That case has 2 rods that slide in and out and there are detents on the rods that keep it "locked" in. Not much can really go wrong with that system that I can think of, but if it wasn't sliding all the way to the locked in position, it might jump out of 2wd. I would first would look at all the linkage and make sure everything's working properly.

03-07-2015, 06:39 PM	#3
bikefool Registered User Join Date: Sep 2013 Location: Occum, CT Posts: 5	Re: 68 K20 won't stay in two wheel drive Once the world thaws out I will crawl under it and check which model it is and check the linkage.

03-07-2015, 06:45 PM	#4
71swb4x4 Senior Member Join Date: Nov 2003 Location: Brookings, SD Posts: 10,497	Re: 68 K20 won't stay in two wheel drive I can't help with your problem, but in 68 you should have a Rockwell T221 transfer case. The 205 started in 1969 but I think some auto transmission trucks had T221's in 1969. __________________ Some people are like slinkies, they aren't good for anything, but you can't help but smile when you see one tumble down the stairs.

03-07-2015, 06:46 PM	#5
hugger6933 Registered User Join Date: Oct 2008 Location: Marianna Arkansas Posts: 7,280	Re: 68 K20 won't stay in two wheel drive Welcome to you from Arkansas. There are lots of knowledgeable people here on this board and are willing to help a fellow trucker out. If you need anything in the paint and body area look me up that is where I hang mostly, Jim

03-07-2015, 07:03 PM	#7
BLT gmc Registered User Join Date: Feb 2014 Location: West Iowa Posts: 1,106	Re: 68 K20 won't stay in two wheel drive GMC used T-221 through most of 69, if not all. It was a mid year change. Chevrolet started with the NP 205 in 69. I agree it sounds like the detents are wore badly. The high hump will have to come off so you can access the top of the case. You do not need to get under the truck to tell the T-221 from the NP 205. T-221 has shifter on the driver side of the 4 spd, The NP 205 shifter is on the passenger side of the 4 spd. Bruce

03-11-2015, 07:23 AM	#8
bikefool Registered User Join Date: Sep 2013 Location: Occum, CT Posts: 5	Re: 68 K20 won't stay in two wheel drive Good to know. It is definitely on the driver's side so it must be a T-221. I will have to check out the detents. __________________ 1968 Chevy K20 292 Flatbed 1970 GMC C3500 350 Dump Bed 2000 Chevy S10 4x4 1971 GMC Sierra Grande



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