uhohthe50

I bought 140 mph speedo for my 86 mustang a little while back and just got around to putting it in. Well I put it in and it wasnt reading the right speed. I took off the cable at the trans and found out that my speedo gear at the trans was stripped because the cable didn't go into the cluster right and got stuck somehow (The cable was pretty short and was hard to get it in the hole on the cluster because my hand didnt fit well in the dash). Well I replaced the plastic gear at the trans and it still doesn't read my speed right. It says that I am going about 10-15 mph slower than what I really am. My car has a 4.10 in the rear and I am using the white gear at the trans. It worked perfectly before I put the 140 mph speedo in. Does anyone have any help for me? Do I just need a different plastic gear at the trans, and if so, what one do I need? Tomorrow I might put back in my old speedo just to see if that works right still, but I figured I would check on here first to save some time.

mjr46

this is the combonation you should have for 4.10's if you have the 7 tooth on the output shaft/ yellow drive gear and white driven gear it won't be completely accurate
http://www.latemodelrestoration.com/...1&comp=LRS

uhohthe50

for some reason that link doesnt work for me

86 5.0L

ok I had a similar experience when I swapped in my 140mph speedo, make sure the needle is dead center on the 0 mark, mine had been twisted and was resting far below the 0 mark, hold the back drum when you twisted the needle

uhohthe50

haha I don't know why I didn't think of that in the first place. I will fix it tomorrow when I get home from work and see if thats the problem.

mjr46

the link works fine for me