91 speedo

[G Matson]

i have recently swaped out my instrument cluster do to the speedo not working at all the one i changed it with came out of a working 91 and it still wont move the needle. but it does jump up to about 30 and back to 0 repeatedly. and i have changed the vss and checked the fuse im all out of ideas so if any one has any suggestion it could be very help full to me thanks for the help.

[1STGENFARMBOY]

Look at where the vss goes into the little gearbox mine was rounded out and would catch and turn alittle bit, and check your vss plug spray some contact cleaner in it, and also take off the gearbox and make shure its in working order. just a thought. Darwin

[IowaCummins]

yupp mine was a spuare shaft about 1/8" or maybe 1/16" right where it goes into teh adaptor. the square shaft was rounded and would jump speeds. i was able to use some stainless wire from aircraft cable, the strands from it and wedge the shaft in place with the outer spline. it worked for me for about 6 months. then it came apart again. so i went to dodge and got a new VSS and it is accurate now and steady.

[1STGENFARMBOY]

I took off the vss and put the shaft in a vice and squezed it till it was alittle wider, like a rectangle don't go to far it won't go back in, mine never did slip again but the electrical part of the vss went bad a year later. replaced with one from napa works good. $56.00 but i found a new old stock one on ebay for $20.00 bucks cheaper.