WTB Speedometer ratio box
 

My 72 GMC 3/4 ton 4x4 is missing the speedometer ratio box. The gear ratio in my truck is 4.56. Any help will be greatly appreciated. Thanks in advance.

Re: WTB Speedometer ratio box
 

How far is it off? I have a few laying around and would part with one if it would work for you. Go down the road for 5 - 10 miles and match your odometer against the mileage markers.

Get the correction ratio and post it here.

Re: WTB Speedometer ratio box
 

low and slow, is this the little metal looking box that the speedometer line screws into to? if so after zeusflash is taken care of , i need one for a 3.73 auto truck, thanks alot.thanks alot.

Re: WTB Speedometer ratio box
 

va_tic,what I need is the little metal box that attaches to the transfer case and the speedo cable attaches to. On 4x4s there was only one speedo drive gear available in the transfercase so the ratio box is used to syncronize the drive gear to the speedometer head for different gear ratios. The ratio box has two gears in it to either speed up or slow down the speedo cable as needed. As to how much mine off....the box is missing completely!

Re: WTB Speedometer ratio box
 

Still need to know the ratio of correction. I have 4 of them.

Re: WTB Speedometer ratio box
 

Sorry low'n slow, I didn't understand what you were asking for. Probably will not get a chance to do this until next weekend...I still have to change the speedo cable.

Re: WTB Speedometer ratio box
 

mines not even on the road yet, but mine is leaking gear oil outa it, thats kinda why i wanted one.so if you do have a extra one after zueusflash, keep me in mind thanks

Re: WTB Speedometer ratio box
 

Did the road test yesterday,had my wife pace me in her Suburban,did the math and it didn't seem right. I installed a ratio box I had laying around(1.202 ratio). Redid the pace test,did the math an got the same answer. Looks like I need a ratio box right around .877. Let me know what you come up with.

Re: WTB Speedometer ratio box
 

I have 1 that is 1:0.9, should slow it down almost 10%. That is about as close as I can come. PM me if you want it.

Re: WTB Speedometer ratio box
 

if you know someone that has a GPS you can use the speedo on it as well...

Tire size will change your ratio as well...