"4WD Lock" Light? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

BigRed76 · 07-16-2011, 02:46 PM

I just recently picked up a '76 or '77 tach cluster, and while taking it apart for cleaning I noticed that it has a warning light under the speedometer that is yellow and says "Four Wheel Lock". Has anyone ever seen this before? And How does it work?

I'm just curious because I've never seen one before and thought it was especially wierd to see on a 70's cluster.

76stepsidechevy · 07-16-2011, 04:04 PM

I have two clusters that I took apart to make a decent tach cluster for my truck and both had that light as well. My 76 is factory part time (np205) 4x4 and didn't have the light. I think the clusters I took apart were 77 and 79.

Prong · 07-16-2011, 04:45 PM

They are for the 203 full-time cases. My 79 auto with the 203 has it. There's a 2 wire lead and switch that runs from the TCase over the floor to that spot in the cluster that lights up when you "lock" the case into 4wd. My other 79 with the SM465/NP205 doesn't have this.

liftlawssuck · 07-16-2011, 06:58 PM

From all my trucks I have had for parts or what not. The ones that had it automatics. Both in 203 or 205 transfer cases. All the manuals did not have it. So I made my manual have it. I think it looks way cool to have that light come on when in 4 wheel drive. I have an 09 chevy and it doesn't even have a light.

76stepsidechevy · 07-16-2011, 11:40 PM

how did you end up doing it?

BigRed76 · 07-17-2011, 07:15 PM

I find it kind of funny that a full time 4wd truck would come with a light to tell you its in 4wd

but I think it would be neat to have a 34 year old truck with a 4wd light
Posted via Mobile Device

liftlawssuck · 07-17-2011, 07:28 PM

One of the trucks I got for parts was an 80 GMC with turbo 400 and 205 case. On top of the 205 on the outer most shift rod is a switch. All the other 205s this is a plug. Remove the plug and install the switch. Now your manual has the 4 wheel lock light. A 203 case has the switch in the shifter itself area if I'm not mistaken. Were as the 205 mated to 400 has it in the case itself. Also it helped that I already had the wiring for the light in the truck. My truck had originally a turbo 350 with a 203 case which had the light. So to make my light come on was real easy.

BigRed76 · 07-17-2011, 08:35 PM

Quote:

Originally Posted by liftlawssuck

One of the trucks I got for parts was an 80 GMC with turbo 400 and 205 case. On top of the 205 on the outer most shift rod is a switch. All the other 205s this is a plug. Remove the plug and install the switch. Now your manual has the 4 wheel lock light. A 203 case has the switch in the shifter itself area if I'm not mistaken. Were as the 205 mated to 400 has it in the case itself. Also it helped that I already had the wiring for the light in the truck. My truck had originally a turbo 350 with a 203 case which had the light. So to make my light come on was real easy.

Hmmm, guess I've never noticed a plug there on my t-case, but I'll have to check it out. Sounds like it has potential to become a cheap extra light on my dash

Prerunner1982 · 07-17-2011, 08:52 PM

Quote:

Originally Posted by BigRed76

I find it kind of funny that a full time 4wd truck would come with a light to tell you its in 4wd

This is because there is a lock option that should not be driven on the street. 4 HI Lock, locks the front and rear axles together in the tcase so when you turn the tires must slip on the driving surface (dirt, grass, etc). When the truck is in 4HI (not lock) the tcase allows the front and rear axles to spin at different rates so that when you turn on the street your tires do not have to try and slip on the road.

If you drive on the street in 4HI Lock it could damage your tcase...

BigRed76 · 07-17-2011, 09:44 PM

That makes sense. Thanks for the info.

BigRed76 · 07-25-2011, 01:12 PM

So could I take a switch from a 203 and put it in my 205? or do I have to find a universal switch that'll fit?

liftlawssuck · 07-25-2011, 03:29 PM

I think the 203 had the switch in the shifter which might be different. Maybe someone else can confirm that. But I think it's different. It's been a LONG time since I've had a 203.

Dan1969 · 07-25-2011, 07:09 PM

Mine has a spelled out "FOUR WHEEL DRIVE", it's a K10 manual.

motornut · 07-26-2011, 10:20 PM

my 203 switch

motornut · 07-26-2011, 10:52 PM

4 wheel lock with manual front hubs it shouldn't but "could" be driven on the street as long as the hubs are off and even better if a kit is put in to make the 203 partime 4lock
with out those mods, drive train would jetison parts soon

07-16-2011, 02:46 PM	#1
BigRed76 Registered User Join Date: Jan 2010 Location: Loveland, CO Posts: 1,921	"4WD Lock" Light? I just recently picked up a '76 or '77 tach cluster, and while taking it apart for cleaning I noticed that it has a warning light under the speedometer that is yellow and says "Four Wheel Lock". Has anyone ever seen this before? And How does it work? I'm just curious because I've never seen one before and thought it was especially wierd to see on a 70's cluster. __________________ Zach 1970 Chevrolet Custom Camper K20 1971 GMC Super K2500, 12V/NV4500 swap in progress 1971 Chevrolet Custom C10 1972 Chevrolet Custom Deluxe C20, 5.3/4L60E 1972 Oldsmobile Cutlass Supreme, 455/TH400, 3.73 posi 2004 GMC Sierra 2500HD, LB7/Allison, CCSB 2005 GMC Sierra 1500, 5.3/4L60E, CCSB

07-16-2011, 04:04 PM	#2
76stepsidechevy Registered User Join Date: Nov 2010 Location: Windsor Locks Posts: 628	Re: "4WD Lock" Light? I have two clusters that I took apart to make a decent tach cluster for my truck and both had that light as well. My 76 is factory part time (np205) 4x4 and didn't have the light. I think the clusters I took apart were 77 and 79.

07-16-2011, 04:45 PM	#3
Prong Registered User Join Date: May 2007 Location: CO Posts: 474	Re: "4WD Lock" Light? They are for the 203 full-time cases. My 79 auto with the 203 has it. There's a 2 wire lead and switch that runs from the TCase over the floor to that spot in the cluster that lights up when you "lock" the case into 4wd. My other 79 with the SM465/NP205 doesn't have this.

07-16-2011, 06:58 PM	#4
liftlawssuck Registered User Join Date: Mar 2011 Location: MA Posts: 353	Re: "4WD Lock" Light? From all my trucks I have had for parts or what not. The ones that had it automatics. Both in 203 or 205 transfer cases. All the manuals did not have it. So I made my manual have it. I think it looks way cool to have that light come on when in 4 wheel drive. I have an 09 chevy and it doesn't even have a light.

07-16-2011, 11:40 PM	#5
76stepsidechevy Registered User Join Date: Nov 2010 Location: Windsor Locks Posts: 628	Re: "4WD Lock" Light? how did you end up doing it?

07-17-2011, 07:15 PM	#6
BigRed76 Registered User Join Date: Jan 2010 Location: Loveland, CO Posts: 1,921	Re: "4WD Lock" Light? I find it kind of funny that a full time 4wd truck would come with a light to tell you its in 4wd but I think it would be neat to have a 34 year old truck with a 4wd light Posted via Mobile Device __________________ Zach 1970 Chevrolet Custom Camper K20 1971 GMC Super K2500, 12V/NV4500 swap in progress 1971 Chevrolet Custom C10 1972 Chevrolet Custom Deluxe C20, 5.3/4L60E 1972 Oldsmobile Cutlass Supreme, 455/TH400, 3.73 posi 2004 GMC Sierra 2500HD, LB7/Allison, CCSB 2005 GMC Sierra 1500, 5.3/4L60E, CCSB

07-17-2011, 07:28 PM	#7
liftlawssuck Registered User Join Date: Mar 2011 Location: MA Posts: 353	Re: "4WD Lock" Light? One of the trucks I got for parts was an 80 GMC with turbo 400 and 205 case. On top of the 205 on the outer most shift rod is a switch. All the other 205s this is a plug. Remove the plug and install the switch. Now your manual has the 4 wheel lock light. A 203 case has the switch in the shifter itself area if I'm not mistaken. Were as the 205 mated to 400 has it in the case itself. Also it helped that I already had the wiring for the light in the truck. My truck had originally a turbo 350 with a 203 case which had the light. So to make my light come on was real easy.

07-17-2011, 09:44 PM	#10
BigRed76 Registered User Join Date: Jan 2010 Location: Loveland, CO Posts: 1,921	Re: "4WD Lock" Light? That makes sense. Thanks for the info. __________________ Zach 1970 Chevrolet Custom Camper K20 1971 GMC Super K2500, 12V/NV4500 swap in progress 1971 Chevrolet Custom C10 1972 Chevrolet Custom Deluxe C20, 5.3/4L60E 1972 Oldsmobile Cutlass Supreme, 455/TH400, 3.73 posi 2004 GMC Sierra 2500HD, LB7/Allison, CCSB 2005 GMC Sierra 1500, 5.3/4L60E, CCSB

07-25-2011, 01:12 PM	#11
BigRed76 Registered User Join Date: Jan 2010 Location: Loveland, CO Posts: 1,921	Re: "4WD Lock" Light? So could I take a switch from a 203 and put it in my 205? or do I have to find a universal switch that'll fit? __________________ Zach 1970 Chevrolet Custom Camper K20 1971 GMC Super K2500, 12V/NV4500 swap in progress 1971 Chevrolet Custom C10 1972 Chevrolet Custom Deluxe C20, 5.3/4L60E 1972 Oldsmobile Cutlass Supreme, 455/TH400, 3.73 posi 2004 GMC Sierra 2500HD, LB7/Allison, CCSB 2005 GMC Sierra 1500, 5.3/4L60E, CCSB

07-25-2011, 03:29 PM	#12
liftlawssuck Registered User Join Date: Mar 2011 Location: MA Posts: 353	Re: "4WD Lock" Light? I think the 203 had the switch in the shifter which might be different. Maybe someone else can confirm that. But I think it's different. It's been a LONG time since I've had a 203.

07-25-2011, 07:09 PM	#13
Dan1969 Registered User Join Date: Jun 2011 Location: OK Posts: 76	Re: "4WD Lock" Light? Mine has a spelled out "FOUR WHEEL DRIVE", it's a K10 manual.

07-26-2011, 10:20 PM	#14
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: "4WD Lock" Light? my 203 switch Attached Images __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350

07-26-2011, 10:52 PM	#15
motornut 78K & 79C Jimmys Join Date: Nov 2009 Location: Ottawa Ont CANADA Posts: 7,901	Re: "4WD Lock" Light? 4 wheel lock with manual front hubs it shouldn't but "could" be driven on the street as long as the hubs are off and even better if a kit is put in to make the 203 partime 4lock with out those mods, drive train would jetison parts soon __________________ John 1978 GMCJimmy4X4-350/203 1979 GMCJimmy4X2-305/350



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