electronic speedometer
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Joined: Dec 2005
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From: north texas
Car: 1990 Trans Am
Engine: LB9 305...350 or 383 coming soon
Transmission: 700r4
Axle/Gears: 4th gen 3.42
electronic speedometer
I changed my rearend from a 2.73 thirdgen to a 4th gen 3.42. I also have an electronic speedometer sensor being a 1990. I plan on using stock 26.1" tires.
1. What am I going to have to change/add for the speedometer to read correctly?
2. Are there speedometer gears on electronic speedometers or what?
Thanks guys!
1. What am I going to have to change/add for the speedometer to read correctly?
2. Are there speedometer gears on electronic speedometers or what?
Thanks guys!
Joined: Aug 2006
Posts: 12,812
Likes: 109
From: Central NJ
Car: 86 Trans Am
Engine: 408 stroker sbc
Transmission: TKO600
Axle/Gears: Moser full floater m9, 3:70 trutrac
transmissioncenter.net
this website has the speedo gears that you need to change thye also have a chart with gear/tire sizes to tell you what gears to get. remember to get the driven gears for electric speedos
i have a 1986 ta with a 700r4 and i just swapped the gears to fix my speedo today. i assume it is similar to yours
the process went a little like this and was not as difficult as i had origionally thought thats why i put if off for over a year
.
a lift is nice but i did mine on jackstands
you need to remove the driveshaft and the torque arm.
my car may be different because i have traction/lift bars but the axle tends to rotate a bit making removal of the torque arm bolts difficult.
once these parts are out disconect the plug going to the sending unit at the rear driverside of the trans, then remove the 10mm bolt on the retaining clip and remove. the sending unit is help in with an o-ring and should pull out with a little force. you may loose a little fluid depending on the angle of the car. next there are 4- 9/16 bolts holding the tailshaft onto the transmission
remove these whille supporting the tail shaft, its light and made of aluminum dont want to damage it!! when the bolts are out the tailshaft comes right off, held in by another o-ring. located on the output shaft is the drive gear and located in the sending unit you removed earlier is the driven gear. the driven gear just pops off simple enough. the drive gear is press-fit onto the output shaft of the trans and has a retaining clip. my gear was on really good and was a little tough to get off. used a 1 1/4 box wrench, levered it on the trans crossmember and beat it with a hammer a few times, rotated the output shaft (oh yea when you doing this part put the car in neutral) as i beat on the wrench. this took a while but it worked, im sure there is a tool for this but i dont have it. keep the retaining clip in mind. as a certain point you have to push the end of it up to clear the gear ( you will see as you do it) on my output shaft there were 2 holes under the clip and the little tab on the clip was in the hole closest to the trans. once you get the gear off, reverse this process to re-assemble. be sure that you line up the groove in the drive gear with the holes in the tailshaft so the clip will go back in.
i dindt loose more that a spit of fluid during this project and it took me 2.5 or 3 hours to complete, i dont know how mechanicaly inclined you are but maybe look into getting a shop to do this if you not. make sure the car is well supported so it doesn't fall on you while you take things apart
the only problem i had was with the bolts holding the torque are to the axle. the nuts were tight as f$#k and required good impact wrinch to remove, and if that wasn't a pain in the ***, you will need to raise and drop the axle a cretain times to remove the bolts, when i jacked the axle up and lowered it down, the angle of the axle and the torque are changed and made the bolts very hard to remove, thats where my traction lift bars came in handy, i was able to load one of them to twist the axle back where i need it to be in order to remove the bolts. this was the only fight i had the whole time
suggested tools
7/16 box wrench
10mm box
9/16 socket
1/2 wratchet
1/2 universal joint
20mm socket
1/2 air powererd impact gun
1 1/4 box wrench
2lb hammer
4 jackstands
floor jack
2x12 wood blocks 2'
there are cutaway views of the transmition available on the wed site i listed and i know i found instructions for this job somewhere but i could remember where
i hope this helps, i dont think i missed anything for it is all still in my head from 1 hour ago
work smart dont get hurt dont do anything stupid make sure the car is supported well at all times
this website has the speedo gears that you need to change thye also have a chart with gear/tire sizes to tell you what gears to get. remember to get the driven gears for electric speedos
i have a 1986 ta with a 700r4 and i just swapped the gears to fix my speedo today. i assume it is similar to yours
the process went a little like this and was not as difficult as i had origionally thought thats why i put if off for over a year
.a lift is nice but i did mine on jackstands
you need to remove the driveshaft and the torque arm.
my car may be different because i have traction/lift bars but the axle tends to rotate a bit making removal of the torque arm bolts difficult.
once these parts are out disconect the plug going to the sending unit at the rear driverside of the trans, then remove the 10mm bolt on the retaining clip and remove. the sending unit is help in with an o-ring and should pull out with a little force. you may loose a little fluid depending on the angle of the car. next there are 4- 9/16 bolts holding the tailshaft onto the transmission
remove these whille supporting the tail shaft, its light and made of aluminum dont want to damage it!! when the bolts are out the tailshaft comes right off, held in by another o-ring. located on the output shaft is the drive gear and located in the sending unit you removed earlier is the driven gear. the driven gear just pops off simple enough. the drive gear is press-fit onto the output shaft of the trans and has a retaining clip. my gear was on really good and was a little tough to get off. used a 1 1/4 box wrench, levered it on the trans crossmember and beat it with a hammer a few times, rotated the output shaft (oh yea when you doing this part put the car in neutral) as i beat on the wrench. this took a while but it worked, im sure there is a tool for this but i dont have it. keep the retaining clip in mind. as a certain point you have to push the end of it up to clear the gear ( you will see as you do it) on my output shaft there were 2 holes under the clip and the little tab on the clip was in the hole closest to the trans. once you get the gear off, reverse this process to re-assemble. be sure that you line up the groove in the drive gear with the holes in the tailshaft so the clip will go back in.
i dindt loose more that a spit of fluid during this project and it took me 2.5 or 3 hours to complete, i dont know how mechanicaly inclined you are but maybe look into getting a shop to do this if you not. make sure the car is well supported so it doesn't fall on you while you take things apart
the only problem i had was with the bolts holding the torque are to the axle. the nuts were tight as f$#k and required good impact wrinch to remove, and if that wasn't a pain in the ***, you will need to raise and drop the axle a cretain times to remove the bolts, when i jacked the axle up and lowered it down, the angle of the axle and the torque are changed and made the bolts very hard to remove, thats where my traction lift bars came in handy, i was able to load one of them to twist the axle back where i need it to be in order to remove the bolts. this was the only fight i had the whole time
suggested tools
7/16 box wrench
10mm box
9/16 socket
1/2 wratchet
1/2 universal joint
20mm socket
1/2 air powererd impact gun
1 1/4 box wrench
2lb hammer
4 jackstands
floor jack
2x12 wood blocks 2'
there are cutaway views of the transmition available on the wed site i listed and i know i found instructions for this job somewhere but i could remember where
i hope this helps, i dont think i missed anything for it is all still in my head from 1 hour ago
work smart dont get hurt dont do anything stupid make sure the car is supported well at all times
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