72Cutlass_442

Hello All,
I have a 1972 Cutlass S that I am in the process of converting to a manual. I have an M21 Muncie 4 speed that i am putting in the car. It came with a yoke that was for a 71 Camaro which does not fit my driveshaft. If I purchase a 32 spline yoke for a 72 cutlass, will it fit my drive shaft? The transmission I removed is a TH350 so the driveshaft length it correct but I want to confirm that the yoke will fit the U-Joint before I purchase the wrong part.

Thanks for the help!

jcdynamic88

why not use the driveshaft/yoke that came out?

72Cutlass_442

I want to use the drive shaft but the yoke that came out of my car was only a 27 spline so it won't fit the M21.

jcdynamic88

i believe the th350 and m20 m21 use the same yoke.do you have m22? if the new yoke doesnt fit the driveshaft there is a combination u joint for that,i think

72Cutlass_442

I thought the M21 and M22 used the 32 and the M20 used the 27? The guy I bought it from said it was an M21 from a 1971 Camaro. Would the Camaro's 32 spline yoke be the same as an Olds 32 spline yoke? I know the Camaro in that year was an f-body and my cutlass is an a-body.

joe_padavano

All M20s and M21s use the same yoke as the TH350.

72Cutlass_442

So I guess I have an M21 with M22 gears? Its the same length as my existing transmission exactly. Either way, will the yoke for a 32 spline fit the U-Joint for a TH350 driveshaft or are the holes for the bearings a different size?

72Cutlass_442

It might just be a normal M21.

joe_padavano

M21 and M22 have the same gear ratios. Apparently the difference in yoke size is due to the year of the trans. Late Muncies (mid-70s) got the large output shaft, same as the TH400. You'll need an Oldsmobile yoke for a 3R U-joint. The one from a TH400 will be the same.

72Cutlass_442

Is the 3R U-joint the same one thats in my drive shaft? It was connected to the TH350.

joe_padavano

Yes, that's why I said it.

72Cutlass_442

Great thanks for the help!

RetroRanger

One other thing to know, the auto trans cars used a 2 peice shaft. Those shafts have been shown to slip over time. Standard shift cars used a 1 piece shaft. You may be a couple dollars ahead to have a new shaft w correct for your trans yoke made now!

SmirchIs#1

Precision "U" joint # 372 I use a lot fore your prob.Also as stated all 71'-74' Muncies have the large output,with one exception being the 70" Chevelle LS6 which also had large yoke.You should also know that all 71'-74' Muncies are 3/4" longer than 63'-70' Muncies.I don't know what trans. you had originaly,but if it was anything other than a TH400 short tail,then your shaft won't work,it will bottom out.Also some th400 yokes are too long for the Muncie & can hit the speedo drive gear.You want to shoot for minimum of 3" yoke/shaft spline engagement