chevyrace47

iTrader: (2)

im trying to switch my th400 to mechanical speedometer. do i have to completely replace the tailshaft housing? i tried searching but found nothing.

01WS6/tamu

iTrader: (36)

Order a VSS sender and reluctor wheel and electrical plug for a 1989 chevy truck with a 4.3 and a TH-400 3 speed tranny. Pull the tail housing, yank the original speedometer gear off. Heat the metal reluctor ring with a torch and slip it onto the extension shaft. Re install the the tail housing and then install the speed sensor and new electrical connector and you are in business.

chevyrace47

iTrader: (2)

is that to go to electric or mechanical? i have a mechanical speedometer, the tranny already has an electric sensor.

01WS6/tamu

iTrader: (36)

Dammit that was to go from mechanical to electric.

To go from electric to mechanical just order all of the parts and install them and it is good to go. I dont remember how to calculate all of the necessary gear colors you need to get the speedo to read accurately.

chevyrace47

iTrader: (2)

Where's the best place to get the parts?

Vince B

iTrader: (1)

You should be able to order what you need from Whatever it takes transmission parts. Look on line to find an online speedo calculator that will ask for some info on what you have in order to get the correct drive and driven gears. You will need tire height and rear end ration. HTH Vince

chevyrace47

iTrader: (2)

alright. i got the drive gear yesterday. is there any chance the old one will come off or the new one will go on with out using a torch? i can get a hold of one but i'd rather not.

Vince B

iTrader: (1)

Its been a while since I've swapped one in the trans. I think one of the shops I worked in had a puller to get in there and pull it out without the use of a torch. If the new gear you have is plastic then it will just slide on and use a stamped steel clip to keep it in place. If the new gear you have is metal then you will need to either heat it with a torch to get it in place. Or if your lucky and have a threaded output shaft you could get creative and use a bolt with some pipe and shims to press it into place. HTH Vince

chevyrace47

iTrader: (2)

ok, i have a puller. so getting the old one off shouldnt be an issue. i'll have to come up with something to get the new one on. since its metal.