Help identifying transmission

[FL71C10]

Here try this...

What the #%$$%$ kind of transmission is this. It's on CL, and the guy just know its from a 292. Is is a granny 4 speed?

http://orlando.craigslist.org/pts/1811919813.html

[Shyguy]

Tried the link, but it said it was removed.

[FL71C10]

I fixed the link

[jamie72]

granny 4 speed.

[Shyguy]

Yep, that is a granny 4 speed. I have a '67 and a '71. I almost had a '64, but my son sold the truck before I could get the transmisson out of it.

They are great transmissons, don't like a lot of hot rodding or speed shifting. I can put mine in granny low and walk along beside the truck when it is idling.

I have heard stories from old farmers that they use to do just that in the fields. They would tie the steering wheel, put the truck in low and walk beside them while loading stuff in the bed of the truck or on a towed trailer.

[292farmer]

def. granny 4 speed id say the sm420 looks just like it heres a sm 420 pic

[FL71C10]

Thanks, it looks so short! Would that be a bolt on replacement for my 6 cyl 3 speed?

[raycow]

The transmission will bolt to a 3 speed bellhousing, but you will need a different driveshaft. Also, 68-up transmissions (either 3 or 4 speed) have a larger front bearing retainer than 67-earlier. Don't worry about this if the seller will let you have the bellhousing shown in his pics, because then you know it will fit.

Ray

[FL71C10]

Is $100 a decent price. He said it includes the shifter. What should I check for?

[raycow]

$100 isn't a bad price if the transmission is in good condition. These boxes don't break easily, but they can get loose and noisy after a lot of use. If the seller will permit, take off the cover and look for obvious damage like corrosion or broken teeth. Whether you look inside or not, shift it into any forward gear except 4th and feel for excessive free play between the input and output shafts. When you put it in 4th it should have almost no free play at all.

That is an SM420, which means the smaller size bearing retainer, so be sure to get the bellhousing if you buy it.

Ray

[LockDoc]

-
Here is a pic of the different transmissions...

RAYCOW: That is an SM420, which means the smaller size bearing retainer, so be sure to get the bellhousing if you buy it.

He could also get an adapter ring here:

http://dennymac.com/mod.php?mod=user...103&page_id=54

and use his existing bell housing. At the time I bought the ring for mine it was $28 shipped. There is also some good swap info there...

LockDoc

[Shyguy]

Originally Posted by raycow

$100 isn't a bad price if the transmission is in good condition. These boxes don't break easily, but they can get loose and noisy after a lot of use. If the seller will permit, take off the cover and look for obvious damage like corrosion or broken teeth. Whether you look inside or not, shift it into any forward gear except 4th and feel for excessive free play between the input and output shafts. When you put it in 4th it should have almost no free play at all.

That is an SM420, which means the smaller size bearing retainer, so be sure to get the bellhousing if you buy it.

Ray

I have read this thread and I am a little confused, but that it is nothing unusal.

We bolted a SM420 to a '69 bell housing I think and it seemed to fit ok. When I drive the truck everything seems ok. I guess my question is will this be a problem in the future?

[raycow]

Originally Posted by Shyguy

We bolted a SM420 to a '69 bell housing I think and it seemed to fit ok. When I drive the truck everything seems ok. I guess my question is will this be a problem in the future?

In short, yes, if the bellhousing was for a 69 truck, not a car, and you didn't use a spacer ring. The bolt pattern is the same on both transmissions, but the bolts do not provide sufficiently accurate centering. The result will be early failure of the transmission front bearing and possible damage to the shafts and gears.

If you haven't noticed any problems yet, you may be in luck. Remove the transmission, install a spacer ring, and reassemble it. No other changes are necessary.

Ray

[Shyguy]

Originally Posted by raycow

In short, yes, if the bellhousing was for a 69 truck, not a car, and you didn't use a spacer ring. The bolt pattern is the same on both transmissions, but the bolts do not provide sufficiently accurate centering. The result will be early failure of the transmission front bearing and possible damage to the shafts and gears.

If you haven't noticed any problems yet, you may be in luck. Remove the transmission, install a spacer ring, and reassemble it. No other changes are necessary.

Ray

Thank you!

I have the original '67 bell housing, so I will use it when I pull the transmission to check the clutch assembly. This truck is not a daily driver and will be the one I am going to do a pretty thorough restoration.

I just added to my restoration notes to change the bell housing.

Again thank you for your help.

[FL71C10]

The sm420 I am looking at is out of a 66 Chevy camper special (allegedly). Will it have synchromesh in all gears? Why won't my old driveshaft from the 3 speed work, because of the length or the yoke? Lastly, will my speedo cable screw right in and work (I know the speed may be off due to gearing changes).

Thanks!

[Shyguy]

My '67 has synchromesh in all forward gears except 1st or granny low as some people call it, so shoud yours.

The speed-o-meter should not be off because of different gearing from a 3 speed to 4 speed. Normally what causes the speed-o-meter to be off is tire size.

I would have to look at both transmissions, but I think the 3 speed is longer than the 4 speed requiring drive shaft mods. If they are the same length the driveshaft should be ok, I would think.

[FL71C10]

I guess you don't want to be shifting into 1st while you're moving anyway.

[raycow]

3 and 4 speed driveshafts are different in design as well as length. The 3 speed shaft has a slip yoke on the front end that slides on the transmission output shaft. This is the same arrangement as on most automatics.

The 4 speed transmission has a flange which is bolted solidly to the output shaft and cannot move endwise. The front U-joint bolts to this flange and there is a slip joint in the shaft behind the U-joint.

Ray

[FL71C10]

Originally Posted by raycow

3 and 4 speed driveshafts are different in design as well as length. The 3 speed shaft has a slip yoke on the front end that slides on the transmission output shaft. This is the same arrangement as on most automatics.

The 4 speed transmission has a flange which is bolted solidly to the output shaft and cannot move endwise. The front U-joint bolts to this flange and there is a slip joint in the shaft behind the U-joint.

Ray

Will an SM465 fit in my truck as well?

[FL71C10]

anybody know about this?

[raycow]

Originally Posted by FL71C10

Will an SM465 fit in my truck as well?

Yes, again subject to the bellhousing center hole difference noted earlier. The 465 would be the "normal" 4 speed for a 71, so if you have a stock 71 bellhousing it will bolt up without any modifications.

Ray

[FL71C10]

OK, so I have my 68 250 with the three speed. The sm465 I am looking at has no bellhousing and came out of a 73 truck. Will the sm 465 bolt up to the 68 bellhousing or do I need to get a different bellhousing?

Sorry to be so slow. Here are pics of the transmission.

Thanks!

[raycow]

Originally Posted by FL71C10

OK, so I have my 68 250 with the three speed. The sm465 I am looking at has no bellhousing and came out of a 73 truck. Will the sm 465 bolt up to the 68 bellhousing or do I need to get a different bellhousing?

Sorry, I was assuming your truck was a 71 because of your sig. If your bellhousing is a 68, the SM465 will bolt up to it with no problems.

Ray

[FL71C10]

The engine and trans are out of a 68. Do I need a high hump transmission tunnel with the sm475?

[raycow]

Originally Posted by FL71C10

Do I need a high hump transmission tunnel with the sm475?

Yes, or be prepared to do some cutting on a low hump.

Ray