Identify my 18-spline

[Deleted member 214]

Long tailshaft with two shifter mounts, so a 70-up B/E piece? Can any body look at the stamping and tell me for sure, or even what it came out of?

Thanks!

 

[Meep-Meep]

The 0G pretty much confirms it's out of a 70 car built in the St. Louis plant (I believe that's G).

 

[Deleted member 214]

That's what I hoped. I bought my 70 G-plant 440 six pack with a 23-spline in it and put in a Kielser 5-speed kit years go I found this tranny just by luck. Synchros were modified to make it a crash box for racing so it will need gone thru but I got it for a good price. I figure if I (or the next owner) ever wanted to back to stock, I'm set.

 

[hendo0601]

Sorta related but not trying to hijack this thread...is there any way to tell the spline count of my 4 speed without physically taking it out and counting? I am looking to buy a new clutch and I can't physically pull the tranny back to check as it is daily driven. Is there a way to tell by checking the numbers stamped on the ID pad? I ran the date code numbers and it was built June 21, 1969

 

[Meep-Meep]

Sorta related but not trying to hijack this thread...is there any way to tell the spline count of my 4 speed without physically taking it out and counting? I am looking to buy a new clutch and I can't physically pull the tranny back to check as it is daily driven. Is there a way to tell by checking the numbers stamped on the ID pad? I ran the date code numbers and it was built June 21, 1969

One way to tell a big spline tranny is to measure the size of the bearing retainer or TO bearing. You might even be able to eye ball it through the release fork dust boot of you know what to look for. The part of the bearing retainer where the TO brg rides is larger than a 23 spline so that would be a dead giveaway.

 

[hendo0601]

is it obviously larger than a 23 spline? This is my first 4 speed car so I dont really have any knowledge to use for reference. Is there something super obvious that I can look for to identify a 23 spline vs 18 spline?

 

[Deleted member 214]

Hijack away! Nope, the VIN on the side of my 18-spline does not show the engine code so that's no help. I'm told they use the same case and tailshaft castings, the only way to tell is to look at the input shaft and bearing retainer. You may be able to drop the inspection cover on the bottom of the bellhousing, or look thru the clutch fork hole, and get an idea. Good luck!

 

[hendo0601]

Yeah I figured as such, but I was really hoping there was some way to tell! I may just have to lay under the car for a little bit and pull the tranny back an inch or so to count the splines then push it back into place then order the clutch kit. I was really hoping to avoid having to do that, but I would rather check and re-check than order and go to put it in and have it be all wrong! Thanks gang!

 

[Meep-Meep]

Actually the 18 spline case and tail shaft are not the same as a 23 spline because of the difference in the OD of the bearings. 23 splines typically use the 307 bearing and the 18 spline uses the 308 size. Some exceptions are the early 18 spline that uses the 307 bearings and the aluminum OD tranny that uses the 308 bearing.

 

[hendo0601]

Actually the 18 spline case and tail shaft are not the same as a 23 spline because of the difference in the OD of the bearings. 23 splines typically use the 307 bearing and the 18 spline uses the 308 size. Some exceptions are the early 18 spline that uses the 307 bearings and the aluminum OD tranny that uses the 308 bearing.

I know this might be kinda grasping at straws here but does anyone know the measurement differences? The clutch in mine is getting worse and worse every day, and I am almost to the point where I am going to have to pull the tranny back to count the splines.

 

[Deleted member 214]

Actually the 18 spline case and tail shaft are not the same as a 23 spline because of the difference in the OD of the bearings. 23 splines typically use the 307 bearing and the 18 spline uses the 308 size. Some exceptions are the early 18 spline that uses the 307 bearings and the aluminum OD tranny that uses the 308 bearing.

I was just going by the fact that my 18 and 23 spline trannys have the same casting numbers. I'm still learnin'.:happy7:

 

[Meep-Meep]

I was just going by the fact that my 18 and 23 spline trannys have the same casting numbers. I'm still learnin'.:happy7:

Oh, in that case you are probably dead on. The difference in the main housing is the machined hole for the bearing but the tail shaft may require a different casting because how it holds the rear bearing. I have both parts so I should look and post some pics.

 

[Meep-Meep]

I know this might be kinda grasping at straws here but does anyone know the measurement differences? The clutch in mine is getting worse and worse every day, and I am almost to the point where I am going to have to pull the tranny back to count the splines.

I want to say there is about 1/4" difference between the two bearing retainers (where the TO brg rides). I'll try to measure them both tomorrow AM.

 

[ply64post]

bearing retainer measurements

I know this might be kinda grasping at straws here but does anyone know the measurement differences? The clutch in mine is getting worse and worse every day, and I am almost to the point where I am going to have to pull the tranny back to count the splines.

hendo

This should help.

Jeff

There were actually 6 different types of bearing retainers:

Bearing Retainer Diameters

Bolt Circle

Diameter

Application

3.70 bolt circle

4.35 diameter

A-body, all years except 1968 Big Block and Overdrive units, All Small Block 1970 and later 23 spline units. 1.248 tube diameter.

3.70 bolt circle

4.35 diameter

1966-1967 18 spline units. 1.417 tube diameter.

3.70 bolt circle

4.80 diameter

1968-1969 Big Block 23 spline units. 1.248 tube diameter.

4.16 bolt circle

4.80 diameter

All 23 spline Big Block units (383-400) 1970 and later. 1.248 tube diameter.

4.16 bolt circle

4.80 diameter

All 1968 and up 18 spline units. 1.417 tube diameter.

4.16 bolt circle

5.125

All OD A-833 units. 1.248 tube diameter

 

[shag766]

I know this might be kinda grasping at straws here but does anyone know the measurement differences? The clutch in mine is getting worse and worse every day, and I am almost to the point where I am going to have to pull the tranny back to count the splines.

bud don't let it go to far or you will be replacing the fly wheel or re-surfaceing it. if they slip to much they use to get heat cracks. i think??