68 C-50 4+2 Spd Trans question - The 1947 - Present Chevrolet & GMC Truck Message Board Network

abilityonline · 04-11-2009, 07:47 PM

Picked up a 68 C50 Dump from a foreclosure. I've got the Dump working great and got the brakes good to go. I took it for a spin and I'm not clear how the 4+2 Spd trans works. It has a knob on the gear shift that I can pull in or out. Can anyone explain how this works and how I should use it properly?

chas350 · 04-11-2009, 07:52 PM

I believe that is a 2 speed axle, when carrying a load one would pop that in and out when shifting. IE: 1st gear low, 1st gear high, 2nd gear low, 2nd gear high, 3rd gear low, 3rd gear high and so on as load/speed/road conditiond vary.

chas

mvfd70 · 04-11-2009, 10:55 PM

You are correct. That would be a 2 speed axle. They are a LITTLE different to drive. It's not like it has 8 gears. You don't really need to shift the axle all the time Example: 1 low to 1 high to 2 low to 2 high to 3 low to three high to 4 low to 4 high. Hope that makes sense.

Some of the gears will "cross" each other. Depends on the gear ratios. Example: 2nd gear high might be geared higher than 3rd gear low.

I've never driven a chevy with a split rear end but some others I've driven you have to clutch to change from low to high or back to low. Others will shift up without clutching but not back down unless you clutch.

This all sounds confusing doesn't it? Well its not really that bed. Best thing to do is take it out and play around with it. You'll figure it out. If I thoroughly confused you let me know.

**special-K** · 04-11-2009, 11:15 PM

The knob activates a solenoid on the center section of the axle.What goes on inside there is a mystery to me.

Wrenchbender Ret · 04-12-2009, 10:19 AM

The shifter inside the diff. is spring loaded. You always have your foot on the gas when you pull/push the button. To upshift pull up on the button, let off the gas till the engine slows down to the speed it will be going after the shift & you will fell a jerk or clunk. Then press on the gas & it should be in the higher gear. To downshift press the button down, let up on the gas & get back on it. When the engine speeds up to the lower gear it will engauge & start pulling. You can use the clutch but it works smoother without it. Split shifting is another lesson.

abilityonline · 04-12-2009, 02:13 PM

excellent replies thanks a ton. All I have left is getting a bunch of little electrical stuff going again, Wipers, washer fluid, blinkers, brake lights .... Then we are good for inspection and ready for the road.

thirdstreettito · 04-12-2009, 07:28 PM

I've driven a bunch of 5+2 trucks, its easy to drive, but not easy to explain to someone over the internet.

04-11-2009, 07:47 PM	#1
abilityonline Registered User Join Date: Feb 2009 Location: Salt Lake City, UT Posts: 57	68 C-50 4+2 Spd Trans question Picked up a 68 C50 Dump from a foreclosure. I've got the Dump working great and got the brakes good to go. I took it for a spin and I'm not clear how the 4+2 Spd trans works. It has a knob on the gear shift that I can pull in or out. Can anyone explain how this works and how I should use it properly? Last edited by abilityonline; 04-11-2009 at 07:48 PM.

04-11-2009, 07:52 PM	#2
chas350 Registered User Join Date: Mar 2007 Location: Connecticut Posts: 581	Re: 68 C-50 4+2 Spd Trans question I believe that is a 2 speed axle, when carrying a load one would pop that in and out when shifting. IE: 1st gear low, 1st gear high, 2nd gear low, 2nd gear high, 3rd gear low, 3rd gear high and so on as load/speed/road conditiond vary. chas __________________ "I'll Procrastinate Tomorrow" quote by LEEVON 71 K10 long fleet (sons truck) new 370hp 355, sm465 np205, 3.73's 33's 70 K20 long fleet 98 G3500 work van

04-11-2009, 10:55 PM	#3
mvfd70 Registered User Join Date: Jan 2007 Location: Opdyke, IL Posts: 775	Re: 68 C-50 4+2 Spd Trans question You are correct. That would be a 2 speed axle. They are a LITTLE different to drive. It's not like it has 8 gears. You don't really need to shift the axle all the time Example: 1 low to 1 high to 2 low to 2 high to 3 low to three high to 4 low to 4 high. Hope that makes sense. Some of the gears will "cross" each other. Depends on the gear ratios. Example: 2nd gear high might be geared higher than 3rd gear low. I've never driven a chevy with a split rear end but some others I've driven you have to clutch to change from low to high or back to low. Others will shift up without clutching but not back down unless you clutch. This all sounds confusing doesn't it? Well its not really that bed. Best thing to do is take it out and play around with it. You'll figure it out. If I thoroughly confused you let me know. __________________ 1978 Chevrolet Silverado 3/4 ton 400 small block. 2000 F-250 Powerstroke 2002 GMC Yukon Denali XL Last edited by mvfd70; 04-11-2009 at 10:57 PM.

04-11-2009, 11:15 PM	#4
special-K Special Order Join Date: Nov 2004 Location: Mt Airy, MD Posts: 85,852	Re: 68 C-50 4+2 Spd Trans question The knob activates a solenoid on the center section of the axle.What goes on inside there is a mystery to me. __________________ "BUILDING A BETTER WAY TO SERVE THE USA"......67/72......"The New Breed" GMC '67 C1500 Wideside Super Custom SWB: 327/M22/3.42 posi.........."The '67" (project) GMC '72 K2500 Wideside Sierra Custom Camper: 350/TH350/4.10 Power-Lok..."The '72" (rolling) Tim "Don't call me a redneck. I'm a rough cut country gentleman" R.I.P. ~ East Side Low Life ~ El Jay ~ 72BLUZ ~ Fasteddie69 ~ Ron586 ~ 67ChevyRedneck ~ Grumpy Old Man ~

04-12-2009, 10:19 AM	#5
Wrenchbender Ret Registered User Join Date: Oct 2005 Location: Overland Park, Ks. Posts: 5,228	Re: 68 C-50 4+2 Spd Trans question The shifter inside the diff. is spring loaded. You always have your foot on the gas when you pull/push the button. To upshift pull up on the button, let off the gas till the engine slows down to the speed it will be going after the shift & you will fell a jerk or clunk. Then press on the gas & it should be in the higher gear. To downshift press the button down, let up on the gas & get back on it. When the engine speeds up to the lower gear it will engauge & start pulling. You can use the clutch but it works smoother without it. Split shifting is another lesson.

04-12-2009, 02:13 PM	#6
abilityonline Registered User Join Date: Feb 2009 Location: Salt Lake City, UT Posts: 57	Re: 68 C-50 4+2 Spd Trans question excellent replies thanks a ton. All I have left is getting a bunch of little electrical stuff going again, Wipers, washer fluid, blinkers, brake lights .... Then we are good for inspection and ready for the road. Last edited by abilityonline; 04-12-2009 at 02:14 PM.

04-12-2009, 07:28 PM	#7
thirdstreettito Resident of Here Join Date: May 2008 Location: Wesley Chapel, FL, USA Posts: 7,716	Re: 68 C-50 4+2 Spd Trans question I've driven a bunch of 5+2 trucks, its easy to drive, but not easy to explain to someone over the internet. __________________ ~Bradley~ 2004 Black GTO LS2/T56 too much to list Miss having a truck



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