Speedo gear reduction box at transfer case??

[70jimmy]

I need the little gear box thingy for the speedometer that attaches to an NP205 transfer case. Its for a 1970 GMC Jimmy with auto transmission. Any ideas???

 

[1-tonmudder]

I have several,what the # on it???

 

[70jimmy]

1563901
1:1.285

 

[1-tonmudder]

Ill check and see if I have that one or one thats close.

 

[70jimmy]

mine is a little off anyway after gear swap and change to 37" tires. then it broke. but at least if i have a speedo that reads i can check it with gps and know how far it is off. This one was 5 mph off,

 

[4X4HIGH]

Most times you can just change the speedo driven gear and not even need the correction box.

 

[70jimmy]

Good Deal! Thanks for the replies. One way or another I will get a speedo working again.

 

[1-tonmudder]

I have 1.2020 and 1.3000.

 

[70jimmy]

How much you want for the 1.2020?

 

[chalet2506]

Have you tried just hooking your speedo cable direct to the 205 to see where that gets you? Mine was closer without the gear box after I swapped axles and tires.

 

[70jimmy]

Well found the problem. A small rod that went from the speedo gear to the box was broken, and a cap was missing off one end of the box also. Once I removed the fitting on the T-case and pulled out the speedo gear the broken part fell out.

So I hooked it up straight. Speedo works but off. When speedo reads 63 I am going 75. Its about 3 mph off at 30 mph and gets worse as you go.

So I am gonna get the box from 1 ton mudder and it should be pretty close to accurate.

Thanks for all the replies.

 

[GreenieK30]

I have about 6 of those too.

 

[70jimmy]

Installed and it's dead on to 1 mph off at all speeds. Thanks 1-Ton

 

[sweetk30]

friend has truck with 60 mph on gps = 5 slow on speedo head.

who has one he can use ?

 

[1-tonmudder]

Installed and it's dead on to 1 mph off at all speeds. Thanks 1-Ton

Good deal,glad it took care of ya.

friend has truck with 60 mph on gps = 5 slow on speedo head.

who has one he can use ?

My GPS is 3mph different in my F-350 and according to those speed limit signs the speedo is dead on so I figure it just looses/gains between the sat and back. I have some more but is 5mpg really worth foolin with???

 

[sweetk30]

my gps is spot on with all the local speed trap notify signs.

but he is fussy like that. if its cheep and will fix it for him then he will prob pay.

 

[1-tonmudder]

if its cheep and will fix it for him then he will prob pay.

It's cheap enuf ($15 shipped) but I can't gaurantee it'll fix it.Probably need to see what ratio it is now and go from there.

 

[sweetk30]

direct cable to tcase. dont know the gear color tho.

 

[70jimmy]

I took mine out and checked it at several different speeds and made a cheet sheet on my window.

then whenn 1-Ton told me what ratios he had I took the speed on the speedo times the ratio and came up with a speed that was very close.

like your friends truck: 55 mph X 1.1 = 60.5, so if you had something close to 1.1 it should be right.

Mine was 63 mph was actually 75. 63 x 1.2020 = 75.726

 

[sweetk30]

sweet thks