3 speed with overdrive swap?

[bonehead]

Happy Thanksgiving to you all, sitting around waiting for the turkey and thinkin'. I have a turbo 400 in my 1966 c-10 but it was originally a 3 speed on the column. Lately I have been thinking of converting it back to a standard shift transmission (i like to shift). I have been reading about the T-5 swaps on the forum, but I am wondering about using the stock Saginaw 3 speed overdrive trans.

I am soliciting opinions about that trans from anyone who has one now or someone who had one in the past as to their drivability and dependability. Does anyone have any experience they can share on the overdrive units? From my reading online it seems that the later Muncie overdrive units were weaker, is that true? Any info would be very helpful.

I haven't bought one yet, this is a pic from the net for reference.

[waspp]

After driving my truck from upstate NY to East TN I have been looking at swapping out the 3 manual as well. This is the first I have heard of an overdrive 3 speed so I am interested as well. It seems the hot set up is the camaro trans with an s10 tailpiece but this OD trans may be much easier.

[63burban]

3 speed overdrives are the cat's pajamas, I've had them in several vehicles.
I buy them up whenever I can, there are different models and ratios starting in 1955 to 1965, 66 they went to the Saginaw version which with a little work, the overdrive unit will fit on the back of a Saginaw four speed.

[63burban4x4]

I'll be running that trans in my suburban, it's together but not on the road yet, so I'm not much help on the drivability. It's behind a 350. I never had one, but drove a few back in the 60's, when I worked for the local Chevy dealer, and my mother had one in a 56 wagon with a 265. My brother wrecked that car before I got my license.

The most work required for my swap was changing the column, since my truck had the SM420 4-speed. I wanted the column shift, although I'm told you can make a floor shift work with the right linkage rods. 3-speed columns are pretty easy to find. My son bought me the OD for Christmas last year, found it on Craigslist, crated it up, and shipped it 2000 miles to me! What a kid! I think that's a great setup.

[1restorick]

! have a three speed overdrive in my 63 truck. I have a strong 350 with AFR heads and it has held up well. Not good for speed shifting with my column shift, but the overdrive turns my 4:11 gears into a 2:88 to 1. Great for cruising the highway. When you ride around in 2nd gear overdrive and tromp on it, it kicks down into second gear and launches!! I love the charm of it. It is also original to my truck.

Rick

[bonehead]

Originally Posted by 1restorick

! have a three speed overdrive in my 63 truck. I have a strong 350 with AFR heads and it has held up well. Not good for speed shifting with my column shift, but the overdrive turns my 4:11 gears into a 2:88 to 1. Great for cruising the highway. When you ride around in 2nd gear overdrive and tromp on it, it kicks down into second gear and launches!! I love the charm of it. It is also original to my truck.

Rick

That's what I was hoping to hear. I have the 4:11 gears as well. Sounds like it might make for a slick combo. I would use the column shift on mine. No plans for speed shifting in my future.

Keep the input coming too. Pros and cons if any.

[waspp]

Will the tail section with the OD unit work on the truck 3 speed box? Or do you have to locate the complete transmission?

[faribran]

I currently have 1 just like the pic in my 67 c10

[Greg63]

Food for thought;
http://67-72chevytrucks.com/vboard/s...d.php?t=595261

Greg.

[bonehead]

Originally Posted by Greg63

Food for thought;
http://67-72chevytrucks.com/vboard/s...d.php?t=595261

Greg.

Yes, That is another way to go. 4 speed OD new process MY6. From what I have read it was a rare RPO in 81-84 GM trucks. Very rare today, maybe as rare as the Saginaw 3 spd overdrive is now. The MY6 4 speed is a Mopar A-833 4 speed with a unique bell housing and shifter. Most recomendations I read says to buy the setup complete as the individual componenents can be hard to source separately.

If I could find one of these MY6 setups complete I would consider it as well.

Thanks for the input Greg

[waspp]

Would anyone know if this OD unit would work with the small 3 speed in our trucks?

http://www.ebay.com/itm/221326107530...84.m1423.l2649

[jjzepplin]

Had two of those overdrives on my local CL and now that I have found a good Saginaw four speed the overdrives are gone. Would have loved to do that to it and now will have to wait. Oh well. Slipping the rebuilt Sag in the 2wd Blazer tomorrow. Heard the solenoids are hard to find if they go bad.

[bonehead]

Does anyone with a 66 that is converting to automatic want to sell their complete and good shifting 3 speed manual setup? Column shifter, pedal, linkage, bell housing, trans, cross member, drive shaft, etc. I think the trans cross member is one year only for 66 (let me know if that is correct or not, due to the emergency brake setup?)

The whole shooting match of parts they don't want. It will offset the cost of their auto trans swap parts cost. I would only be interested in something close to Charlotte so I can be sure to get all the parts, clips, springs, etc and pick it up in person to avoid shipping cost.

I'm thinking that I can convert mine back to standard shift now and then upgrade to OD when I find the parts.

Anyone doing this swap in the next 6 months, I'm in no hurry? I will sell my fresh turbo 400 when I am done.

[Mike K]

I replaced my old 3 speed with one of the 3 speed overdrive units and am very pleased with it. It is behind my original 250-6, so I'm not over powering it. But it sure is nice to be turning less RPMs at high way speed. What I had to do was get the drive shaft shortend and purchase a wiring kit that I found on eBay.

[Flthead]

I've had the 3 spd overdrive in my '70 short step 400 small block 3.73 gears. Been in it for 15 + years . It's ok but have a Camaro/s10 t5 swap waiting to go in there. Need something better for hi ways then the 3 spd overdrive offers . Have 2 3spd overdrive units in n.j.

[slorio]

Flthead:
I would check ratios before you take out that 3 speed with overdrive. I believe 3rd with overdrive is a .7 to 1 ratio. The ratios on the T-5's are unlikely to slow your RPM's down. The inliners.org lists their 5th gear ranging from .72 to 1 to .86 to 1.

If you want to slow down your RPM's you would be better off changing your rear end ratio from the 3.73 you have to something numerically smaller.

Regards,
Steve
New Orleans

PS I have the full synchro 3 speed with overdrive behind by GMC 305E V6. It was a great addition to my truck. Haven't done a thing to it since I installed it years ago.

[Flthead]

Originally Posted by slorio

Flthead:
I would check ratios before you take out that 3 speed with overdrive. I believe 3rd with overdrive is a .7 to 1 ratio. The ratios on the T-5's are unlikely to slow your RPM's down. The inliners.org lists their 5th gear ranging from .72 to 1 to .86 to 1.

If you want to slow down your RPM's you would be better off changing your rear end ratio from the 3.73 you have to something numerically smaller.

Regards,
Steve
New Orleans

PS I have the full synchro 3 speed with overdrive behind by GMC 305E V6. It was a great addition to my truck. Haven't done a thing to it since I installed it years ago.

Ya , I was going to go to a 3.42 gear first then decide on the t5

[Flthead]

3 speed overdrive truck trans

[Flthead]

Here's another pic

[bonehead]

What are those going for $$ in your neck of the woods... just wondering?? I would like to source one locally if possible so I can personally check its condition prior to purchase.

[jayoldschool]

What I had to do was get the drive shaft shortend

I thought these units were the same length as the stock 3 speed non-OD trans?

[ray_mcavoy]

Originally Posted by jayoldschool

I thought these units were the same length as the stock 3 speed non-OD trans?

From what I have seen, some of the non-OD 3-speeds had longer tail sections than others.

I think the OD 3-speed is about the same as the long-tail non-OD trans but about 5" longer than the short-tail non-OD trans.

Dad found this OD 3-speed a couple years ago:

We've been planning on swapping it into his 66 but have some other projects to finish up first. His truck currently has the short-tail 3-speed so the driveshaft will have to be shortened.

Also, his old trans has the non-synchronized 1st gear. This OD trans is the fully-synchronized type and the shift levers are farther apart on the side. The 2nd/3rd lever looks to be roughly in the same place but the 1st/rev lever is farther back. I think that might require some modifications to the 1st/rev linkage rod ... he wants to keep the stock column shifter.

[Lugnutz65]

Originally Posted by slorio

Flthead:
I would check ratios before you take out that 3 speed with overdrive. I believe 3rd with overdrive is a .7 to 1 ratio. The ratios on the T-5's are unlikely to slow your RPM's down. The inliners.org lists their 5th gear ranging from .72 to 1 to .86 to 1.

If you want to slow down your RPM's you would be better off changing your rear end ratio from the 3.73 you have to something numerically smaller.

Regards,
Steve
New Orleans

PS I have the full synchro 3 speed with overdrive behind by GMC 305E V6. It was a great addition to my truck. Haven't done a thing to it since I installed it years ago.

I am not aware of any Camaro (V6 or V8) that had a T5 with a 0.86 OD gear.

The WC Camaro V8 T5 is not all that easy to find, but persistence will pay off. I have 3 of them and they all have the 0.63 OD gear. The WC Camaro V8 T5 with the 0.73 OD gear is mysteriously rare. The NWC Camaro V8 T5 is not as hard to find, but some people get antsy when they hear NWC as if it had cooties or something! LOL!!

If you run the numbers, a 0.63 OD will NOT work well with a 3.42 rear. In fact, another forum member here has a 250ci mated to a T5 with a 0.72 OD and a 3.42 rear and he said lugging would occur on medium inclines. With the 0.63 OD, the RPMs are likely to be low and lug the engine unless you have a 3.73 0r 4.11. GM did use the 0.63 OD in the 305ci V8 Camaro with a 3.42 rear (or was it a 3.08?) but the Camaro had a 215/65R15 tire which is 26" and a more streamlined body.

If your engine has enough horsepower, then the 0.63 OD will really cruise nicely with a V8. For an L6, I recommend 0.72, 0.73 or 0.76 OD gears.

Even a T5 with a 0.86 OD from a 4 banger S10 will cruise nicely with a 3.42 or a 3.08.

I welcome you to read more on my T5 Info Page.

[AcampoDave]

For my shortbed, I mated a 3 ring Saginaw 4 spd to a 276 rear end on a warmed up 283 and found it to work better than I had anticipated. The low 1st gets me going pretty well and the 4th gear feels like overdrive. It seems 2nd can wind up to 60 mph and third will get me up to around 80 mph if needed. Fourth is a cruiser on a flat highway and wil readily handle city driving at 35 mph or higher. I didn't plan this combo but it kinda fell into my lap so I went with it. With 235/75-15 tires I pretty much got a 3 speed overdrive in a different kind of package.

[Lugnutz65]

Originally Posted by AcampoDave

I mated a 3 ring Saginaw 4 spd to a 276 rear end on a warmed up 283 and found it to work better than I had anticipated. The low 1st gets me going pretty well and the 4th gear feels like overdrive. It seem 2nd can wind up to 60 mph and third will get me 80 if needed. Fourth is a cruiser on a flat highway and will handle city driving at 35mph or higher. I didn't plan this combo but it kinda fell into my lap so I went with it. With 235/75-15 tires I pretty much got a 3 speed overdrive in a different kind of package.

Me, being a novice with a lot of truck terminology, I gotta ask.
Is the "3 ring 4 speed" you mentioned the same as what some call a granny gear 4 speed? Paired with a 2.76 rear should be a good match. Any idea what the actual tranny gearing is? 4th would be a 1:1 ratio, but with a 2.76 rear, 70 MPH would be right at 2238 RPMs. Nice!