$600 2000 C3500 CCLB

[bluex]

Glad you're enjoying yours! Hope to be doing the same with mine soon.
I wonder why no one has come up with a legitimate fix for 400 taillights? I guess it's harder than it seems. I yet to see aftermarket lights that are as visible (bright) as OEMs are in the day or night.

Some aftermarket lights do away with the boards an use regular 3157 style sockets. I see them from time to time on ebay or rock auto usually has them in the ANZO line but they are pretty pricey....

 

[Stumpy]

ANZO is the direction I'm going. They look close to stock, but like stated, do away with the crappy board the stock lights have.

 

[crashnitup]

I still want to go bigger than the 245’s currently on the truck, so I’ll just see what it reads when I throw those on, maybe it’ll get it closer lol

shoot, you wanna go bigger, i need to go smaller. These 285s are blocking my lowering kit from happening

 

[stutaeng]

Makes me think it doesn't have the stock gearing.

I have a similar truck K3500. A few months ago I discovered the same thing running 78 MPH on the dash is actually 70MPH on the speedometer ON LT265/75/R16! I created a thread and chased my tail for a bit thinking someone had swapped 4.56 gears... can't remember where it is. Mine also is listed with LT245/75/R16 on the door sticker BTW.

I think I confirmed 4.10s on mine by jacking the rear and counting the driveshaft to wheel rotations, but never figured out the issue. If I recall, the computer (from a handheld) scanner is close to the actual speed compared to my GPS, so not sure what the deal is...I had actually forgot about this problem on mine, LOL.

When I was driving it more regularly I thought I was hauling a$$ and people were still passing me, LOL. Until my brother drove with me once and told me my speedo was off.

 

[frito-bandito]

I have a similar truck K3500. A few months ago I discovered the same thing running 78 MPH on the dash is actually 70MPH on the speedometer ON LT265/75/R16! I created a thread and chased my tail for a bit thinking someone had swapped 4.56 gears... can't remember where it is. Mine also is listed with LT245/75/R16 on the door sticker BTW.

I think I confirmed 4.10s on mine by jacking the rear and counting the driveshaft to wheel rotations, but never figured out the issue. If I recall, the computer (from a handheld) scanner is close to the actual speed compared to my GPS, so not sure what the deal is...I had actually forgot about this problem on mine, LOL.

When I was driving it more regularly I thought I was hauling a$$ and people were still passing me, LOL. Until my brother drove with me once and told me my speedo was off.

I actually searched for this issue on here and read your thread on this. Idk if I’ll chase it too much

 

[stutaeng]

I actually searched for this issue on here and read your thread on this. Idk if I’ll chase it too much

Weird that they both are off about the same amount. I had to dig that tread...it does look like the ECU is getting fed the correct MPH. Somehow the cluster is not?

Of course, it's the instrument cluster we use to "guage" how fast we are going. It will be hard to get a speeding ticket on our trucks, LOL.

 

[skylark]

I still want to go bigger than the 245’s currently on the truck, so I’ll just see what it reads when I throw those on, maybe it’ll get it closer lol

3.6% taller. 70 on the speedo would be 72.5 in ground speed.

 

[stutaeng]

No real update yet, I am working on a couple of small things that I’ll post pics when I finish likely this weekend.

However, I did drive it tonight down the road to pick up my daughter from a friend’s house, and discovered I have no lights outside except headlights. The dash lights come on with the switch and I can switch the headlights from low to high beam...but no tails or front marker/parking lights...I’ll have to figure out what’s going on there.

Did you figure this out? I also had an issue with no brake tail lights. Had to change the brake light switch and multi function lever. I was not able to determine which one was faulty.

The PO had removed the big brake fuse, and I discovered that after I had changed both of those parts, then found some hacked wires, so that fixed as well and the issue was resolved.

 

[frito-bandito]

3.6% taller. 70 on the speedo would be 72.5 in ground speed.

That’s close enough for me!

 

[frito-bandito]

Did you figure this out? I also had an issue with no brake tail lights. Had to change the brake light switch and multi function lever. I was not able to determine which one was faulty.

The PO had removed the big brake fuse, and I discovered that after I had changed both of those parts, then found some hacked wires, so that fixed as well and the issue was resolved.

Yes, my issue turned out to be the headlight switch, it crumbled in my hand when I unsnapped it from the dash bezel lol. Plugged a new one in and I haven’t had any more issues.