The 1947 - Present Chevrolet & GMC Truck Message Board Network







Register or Log In To remove these advertisements.

Go Back   The 1947 - Present Chevrolet & GMC Truck Message Board Network > 47 - Current classic GM Trucks > The 1967 - 1972 Chevrolet & GMC Pickups Message Board

Web 67-72chevytrucks.com


Reply
 
Thread Tools Display Modes
Old 01-15-2015, 08:52 AM   #1
Bjj_junkie
Registered User
 
Join Date: Jun 2014
Location: Miami beach Florida
Posts: 16
buy new transmission but don't understand gear ratios

hey everyone, after doing as much research as i can and talking to the few people i know that know some about the subject. i concluded that ill buy the same transmission i have in the truck now just rebuilt from a site. i have a 72 step side with a 250 and 3 speed floor shifter. the transmission is no good as it is and it seems to cost more to get it rebuilt. I'm not sure if its a muncie or saginaw but ill find out once we pull it out. after looking online for some time i finally found a site that sells both muncie and saginaw rebuilt 3 speeds but theres 5 different gear ratio options and i have no idea which would be the one i need. If anyone could help me understand this a bit more and recommend which would be best for a daily driver that would be awesome.

they start at 254-150 and go up to 351-189

heres the site I'm talking about if you can make sure this is the transmission ill even need because i see the site is strictly racing so I'm not %100 sure this is even what ill need http://www.smileysracing.com/shopping/?ic=1574

thanks a bunch
Bjj_junkie is offline   Reply With Quote
Old 01-15-2015, 09:14 AM   #2
Lattimer
Registered User
 
Lattimer's Avatar
 
Join Date: Jan 2013
Location: Mickleton, NJ
Posts: 1,776
Re: buy new transmission but don't understand gear ratios

The numbers they are giving you are the first and second gear ratio. So 1st is 2.54:1, second is 1.50:1, and 3rd will always be 1:1.

The higher number is a lower gear, so that 3.51:1 1st gear will be really low, and you'll need to shift out of first before you get moving very fast.

That being said----those transmissions are stock units rebuilt for circle track racing. Its not the direction I would go. I can't imagine that you couldn't get your trans rebuilt cheaper with stock parts. The 3-speeds are pretty simple. Usually they need a couple of bearings, new synchros and seals.

Whats going on with the trans you have?
__________________
Shawn

1970 Chevy C-10 SWB, 350, TKO 600 5 speed
My build http://67-72chevytrucks.com/vboard/s...d.php?t=559881
Lattimer is offline   Reply With Quote
Old 01-15-2015, 09:25 AM   #3
Bjj_junkie
Registered User
 
Join Date: Jun 2014
Location: Miami beach Florida
Posts: 16
Re: buy new transmission but don't understand gear ratios

Quote:
Originally Posted by Lattimer View Post
The numbers they are giving you are the first and second gear ratio. So 1st is 2.54:1, second is 1.50:1, and 3rd will always be 1:1.

The higher number is a lower gear, so that 3.51:1 1st gear will be really low, and you'll need to shift out of first before you get moving very fast.

That being said----those transmissions are stock units rebuilt for circle track racing. Its not the direction I would go. I can't imagine that you couldn't get your trans rebuilt cheaper with stock parts. The 3-speeds are pretty simple. Usually they need a couple of bearings, new synchros and seals.

Whats going on with the trans you have?
yeah thats what i was thinking but i can't seem to find anyone else that sells them. and as for getting it rebuilt, I've called most local places i can find online and they either don't do them or couldn't give me a straight number just anything ranging from 600 - 1700. and I'm not too sure whats wrong with it, I'm new to all this and learning as i go but it doesn't seem to fall into gear. we only drove it for a few mins around the storage after the tow truck dropped it off but it just felt loose and wouldn't grab first very well.
Bjj_junkie is offline   Reply With Quote
Old 01-15-2015, 02:59 PM   #4
Lattimer
Registered User
 
Lattimer's Avatar
 
Join Date: Jan 2013
Location: Mickleton, NJ
Posts: 1,776
Re: buy new transmission but don't understand gear ratios

Quote:
Originally Posted by Bjj_junkie View Post
yeah thats what i was thinking but i can't seem to find anyone else that sells them. and as for getting it rebuilt, I've called most local places i can find online and they either don't do them or couldn't give me a straight number just anything ranging from 600 - 1700. and I'm not too sure whats wrong with it, I'm new to all this and learning as i go but it doesn't seem to fall into gear. we only drove it for a few mins around the storage after the tow truck dropped it off but it just felt loose and wouldn't grab first very well.
If its still a column shift, it may be the shift linkage is hanging up/not adjusted and have nothing to do with the actual transmission.
__________________
Shawn

1970 Chevy C-10 SWB, 350, TKO 600 5 speed
My build http://67-72chevytrucks.com/vboard/s...d.php?t=559881
Lattimer is offline   Reply With Quote
Old 01-15-2015, 02:53 PM   #5
Fitz
Account Suspended
 
Join Date: Jan 2007
Location: Tucson
Posts: 2,183
Re: buy new transmission but don't understand gear ratios

Quote:
Originally Posted by Bjj_junkie View Post
hey everyone, after doing as much research as i can and talking to the few people i know that know some about the subject. i concluded that ill buy the same transmission i have in the truck now just rebuilt from a site. i have a 72 step side with a 250 and 3 speed floor shifter. the transmission is no good as it is and it seems to cost more to get it rebuilt. I'm not sure if its a muncie or saginaw but ill find out once we pull it out. after looking online for some time i finally found a site that sells both muncie and saginaw rebuilt 3 speeds but theres 5 different gear ratio options and i have no idea which would be the one i need. If anyone could help me understand this a bit more and recommend which would be best for a daily driver that would be awesome.

they start at 254-150 and go up to 351-189

heres the site I'm talking about if you can make sure this is the transmission ill even need because i see the site is strictly racing so I'm not %100 sure this is even what ill need http://www.smileysracing.com/shopping/?ic=1574

thanks a bunch
The GrimJeeper has a great final drive ratio calculator on line. Choose the trans you want (gear ratios are built in ) or specify your own trans ratios, pick a rear axle ratio and tire size and it will tell you RPM vs MPH in any gear or RPM at any speed in any gear. That way you can see just how the tires and transmission choices affect engine RPM.

http://www.grimmjeeper.com/gears.html
Fitz is offline   Reply With Quote
Old 01-15-2015, 03:10 PM   #6
67 cst swb
Senior Member
 
67 cst swb's Avatar
 
Join Date: Nov 2001
Location: Rapid City, SD
Posts: 2,281
Re: buy new transmission but don't understand gear ratios

That could be a clutch adjustment or other easy fix.
It is difficult for a shop to give a rebuilding price over the phone.
This is because a lot of internal parts are reused on a Manual Transmission.
Such as gears, shafts, etc... but if any of these are broke, worn, or missing (as in a trans brought into a shop in a box) then things can start adding up.

I would maybe take the vehicle as is to a mechanic (not Goodyear or Meineke, etc...) for them to look at. A reputable Mechanic can determine if its a clutch issue or an internal transmission issue.
__________________
My Trucks:
1967 Chevrolet Short Wide Box 327 TH350 9" w/3.90 gears paint will be White - Current Project
1967 Chevrolet Custom LWB 283 TH400 3.73 Posi, no-AC, no-PS, no-PB, bench-seat, small-window - mostly orig driver
1967 Chevrolet CST LWB originally a 327 TH400 3.73 Posi AC PS PB, had Buddy Buckets, Small Window - parts truck
1967 Chevrolet CST LWB, 283 MT 3.73 had Buddy Buckets, Panoramic Window - parts truck
2001 Chevrolet 3500 2WD Crew Cab Dually 8.1L Allison White
67 cst swb is offline   Reply With Quote
Old 01-15-2015, 07:27 PM   #7
Bjj_junkie
Registered User
 
Join Date: Jun 2014
Location: Miami beach Florida
Posts: 16
Re: buy new transmission but don't understand gear ratios

Quote:
Originally Posted by 67 cst swb View Post
That could be a clutch adjustment or other easy fix.
It is difficult for a shop to give a rebuilding price over the phone.
This is because a lot of internal parts are reused on a Manual Transmission.
Such as gears, shafts, etc... but if any of these are broke, worn, or missing (as in a trans brought into a shop in a box) then things can start adding up.

I would maybe take the vehicle as is to a mechanic (not Goodyear or Meineke, etc...) for them to look at. A reputable Mechanic can determine if its a clutch issue or an internal transmission issue.
Thank you, thing is it's not registered at the moment so every time we move it it's about a 100 bucks to tow it around. But if nothing else that might be my only option
Bjj_junkie is offline   Reply With Quote
Reply

Bookmarks

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 06:56 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Copyright 1997-2022 67-72chevytrucks.com