ssexton1
Member
I have a 1954 3100 truck with Hydramatic transmission.
What part is needed to install the cable to the transmission?
What part is needed to install the cable to the transmission?
-
We have upgraded our forum software! See here for details.
Speedometer cable to Hydramatic Transmission
- Thread starter ssexton1
- Start date
The cable should be the same. There is a screw in gear/cable drive assembly in the tailhousing of the transmission. They show up on ebay regularly. Is that the question you were asking? This one is for a 3/4 ton truck but it gives you an idea of what you are looking for. http://www.ebay.com/itm/NOS-CHEVROL...Parts_Accessories&hash=item4619676172&vxp=mtr
Is there just a 1" or so diameter hole in the tail housing now or does it have a threaded "plug" in that hole? The hole or plug is on the left side just to the rear of where the tail housing bolts onto the main case. If the plug is there then all that is needed is a longer speedometer cable that what went on the 3sp trans. Picture shows a 54 tranny with the plug in place. Inside the plug is what is called the "driven" speedometer gear and on the transmission output shaft is the "drive" gear. If the Hydramatic trucks didn't have a 3.90 rear gear like the other trucks you will have to find the correct set of drive and driven gears but the car gears are the same size and design so it's easy to do. Sorry I don't know how to draw a circle around the plug like smart people do.
Attachments
ssexton1
Member
Sandy,
If you look closely you should see a female square hole in the center of that threaded plug. The speedometer cable has a square male end to fit into that hole. If you can't see a square hole there is a good chance the end of the cable is twisted off in there. Use a small wire or tooth pick to see if the hole is open. One thing I do before screwing on the speedometer cable is to raise the rear wheels off the floor and hold with some GOOD jack stands. The engine is started and the transmission is put out into "Drive"; if the square hole spins then all is good as far as the drive and driven gears are concerned. Hook the cable big end to the transmission and little end to the speedometer. It is easier to feed the cable up from below because you're threading the little end through the firewall hole. Once hooked up and the wheels still off the floor you should get a reading on the speedometer. We take the car/truck down the road with a GPS to compare the real speed with what the speedometer shows. If the speedometer reads like 60mph and the GPS reads 45mph then the driven gear needs to be slowed down 25%. You can check out "speedometer gears" on a place like TCI or just google "speedometer drive and driven gears" to give you several sites. Count the teeth on your drive and driven gear and figure out what tooth combination will slow the driven gear by 25% ie fewer teeth on the drive gear or more teeth on the driven gear or a combination of both. The threaded plug is removed by removing a little tab the holds it to the tail housing (usually takes a 7/16 wrench) and then if it doesn't twist out with your fingers pad a pliers jaws with some tape and twist out. Tape protects threads on plug. Once out the driven gear just slides out of the plug. If lucky it will work with just more teeth on the driven gear because you have to pull off the tail housing to get to the drive gear. Of course if the speedometer reads like 45mph and the gps shows 60mph then everything is reversed. Have fun;
If you look closely you should see a female square hole in the center of that threaded plug. The speedometer cable has a square male end to fit into that hole. If you can't see a square hole there is a good chance the end of the cable is twisted off in there. Use a small wire or tooth pick to see if the hole is open. One thing I do before screwing on the speedometer cable is to raise the rear wheels off the floor and hold with some GOOD jack stands. The engine is started and the transmission is put out into "Drive"; if the square hole spins then all is good as far as the drive and driven gears are concerned. Hook the cable big end to the transmission and little end to the speedometer. It is easier to feed the cable up from below because you're threading the little end through the firewall hole. Once hooked up and the wheels still off the floor you should get a reading on the speedometer. We take the car/truck down the road with a GPS to compare the real speed with what the speedometer shows. If the speedometer reads like 60mph and the GPS reads 45mph then the driven gear needs to be slowed down 25%. You can check out "speedometer gears" on a place like TCI or just google "speedometer drive and driven gears" to give you several sites. Count the teeth on your drive and driven gear and figure out what tooth combination will slow the driven gear by 25% ie fewer teeth on the drive gear or more teeth on the driven gear or a combination of both. The threaded plug is removed by removing a little tab the holds it to the tail housing (usually takes a 7/16 wrench) and then if it doesn't twist out with your fingers pad a pliers jaws with some tape and twist out. Tape protects threads on plug. Once out the driven gear just slides out of the plug. If lucky it will work with just more teeth on the driven gear because you have to pull off the tail housing to get to the drive gear. Of course if the speedometer reads like 45mph and the gps shows 60mph then everything is reversed. Have fun;
Sandy,
Would like to see your finished truck. Along about April, if gas is still down, my wife and I are going to drive the old 37 Buick to northwest Iowa near the Minnesota border. We usually go through KC on the by-pass that hits 29 near the airport but also can use 35 or 71. Anything near your neighborhood? The 37 Buick is kinda like it's owner, the exact same age, covering getting thin on top, and a little slow.
Would like to see your finished truck. Along about April, if gas is still down, my wife and I are going to drive the old 37 Buick to northwest Iowa near the Minnesota border. We usually go through KC on the by-pass that hits 29 near the airport but also can use 35 or 71. Anything near your neighborhood? The 37 Buick is kinda like it's owner, the exact same age, covering getting thin on top, and a little slow.
ssexton1
Member
I would love to meet you in April. I do live near 71 highway in the south side of the city, almost to Grandview, Missouri, but would consider meeting you at a location that would not be out of your way.
Thank you for your excellent post. It make me understand a little better what is going on.
Thank you for your excellent post. It make me understand a little better what is going on.
Zig
Member
Stop by!!!
Evan, we might be able to provide you a stop along the way! We are right on 69 highway, if that is how you are getting up here. You might take 71 though, and that is a bit further East of here. Anyway, it would be fantastic to meet you!
Evan, we might be able to provide you a stop along the way! We are right on 69 highway, if that is how you are getting up here. You might take 71 though, and that is a bit further East of here. Anyway, it would be fantastic to meet you!
51papy
Member
Evan
I would like to shake your hand and say thanks for all the help in person. I'm south of KC but I work in KC several days a week. Let us know when your coming through.
Papy
I would like to shake your hand and say thanks for all the help in person. I'm south of KC but I work in KC several days a week. Let us know when your coming through.
Papy
Guys,
Makes me happy for all the warm invitations. One thing about our trips is that we are on no time schedule and don't mind detours. Our normal route is north on 35 to the west KC by-pass with a modern car but with an old car/truck we go up 69 to Miami, Oklahoma, and then across the toll road to Joplin where we can choose either old business 71 or the new one. Have also followed 75 all the way from Dallas to Nebraska City, Nebraska, and cross over into Iowa there. Like I say, we're flexible. Will watch the weather come April and give everyone a likely launch date. Thanks all;
Makes me happy for all the warm invitations. One thing about our trips is that we are on no time schedule and don't mind detours. Our normal route is north on 35 to the west KC by-pass with a modern car but with an old car/truck we go up 69 to Miami, Oklahoma, and then across the toll road to Joplin where we can choose either old business 71 or the new one. Have also followed 75 all the way from Dallas to Nebraska City, Nebraska, and cross over into Iowa there. Like I say, we're flexible. Will watch the weather come April and give everyone a likely launch date. Thanks all;