The Stovebolt Site Forums The Shop Area Driveline Just landed an overdrive trans

I just bought a 3 speed overdrive trans that came out of a 67 chevy truck. It has the 7 bolt side cover, so I believe it is a synchro 1st gear Saginaw.

I'm driving up to Iowa this weekend to pick it up. The seller says it is complete including the wiring harness, solenoid, governor and the overdrive pull cable. The pictures show a very complete trans.

I'm looking for advice from you guys that have bought/installed one. What do I need to make sure I get when I pick it up? Are there any extra bits I need to grab from the vehicle?

If they are present, get the kickdown switch and relay.

If you don't I can show you how to wire it with a toggle switch and a Bosch type relay.

Congrats on finding the tranny. You'll love it.

That's a great find. You will need a fine spline front yoke to use it in your 58. You will also need to modify your shift levers somewhat as the later trans has a different side cover and shift arms.
Fred

Does anyone have a picture or diagram of the kick down switch and relay? Just want to know what I'm looking for.

Is it possible to harvest the input shaft and shifter arms from the current trans to use on the new one?

that is a nice tranny, I have used them before.
I would like to recommend before you purchase that transmission, remove the side cover (7 bolt)and inspect it. If it have heavy wear inside may indicate hard use, most important of all WATER damage, if you see water damage(rust from sitting outside or stored in basement and had a flood), most likely the parts in the overdrive unit will have pitted or corroded and are hard to find replacements some parts are interchangeable with the older units, the gears inside of the transmission itself are interchangeable with other Saginaw trans as long as you have right ratios.
I have seen trans in my past with water damage and usually most parts are ruined,
good luck with your find.

The side covers are completely different so the shift arms won't interchange. Some modification to the rods is necessary as the spacing on the side covers is different. The fine spline yoke is common to TH350, Powerglide, and later 4 speed (car) transmissions. As mentioned, it's always a good idea to pull the side cover to prevent surprises when you get it home.
Fred

Ok. I didn't get a chance to check this site before I drove up to get the transmission, so I didn't pull the side cover. It was recently pulled from a running 67 chevy truck. The seller said he drove the truck home about 50 miles and it worked like a charm. He seemed like a real standup guy so I feel like he's telling the truth. Call it gut instinct.

It looks good from the outside and doesn't show any evidence of water contamination. I'll pull the cover this weekend to have a look.

On a good note, he had all the wiring bundled up and ready to go when I got there. I got the pull cable, relay and the carb kick down switch. The trans is complete with the governor and the solenoid. The wiring on the trans looks solid and complete as well. Barring any unforeseen surprises inside the trans, I'm pretty happy with the purchase. I'll post again once I get a look at the insides.

First of all; someone should have warned me about how hard it is to get the side cover back on once you take it off! :-) I got it off in about 5 minutes and then spent about 30 minutes trying to put it back on. I thought I was going to lose my mind getting the shifting forks to line up with the shifting collars (or whatever they're called) inside the trans.

On a positive the, the inside looked excellent. Clean and well lubed with no evidence of chipped/damaged gears. If I didn't know any better I'd say it may have been rebuilt/freshened up lately. See pictures at:
http://i1053.photobucket.com/albums/s461/biglarry3/IMG_0683_zps86afb7c5.jpg
http://i1053.photobucket.com/albums/s461/biglarry3/IMG_0677_zps04261b4d.jpg

If you page through the album you can see varying shots of the transmission. You can also see the evidence of the 3-4 hours I spent with a putty knife, screwdriver and wire brush cleaning 40 years worth of gunk of the tranny. All cleaned up it looks pretty good. I may hit it with some engine degreaser and take it to the car wash to blast off the remainder of the grease. I'll be sure to tightly wrap the governor and solenoid so as not to get them wet.

I've got a few questions:

1. If I wanted to paint it to preserve it, how would I go about that?
2. With the tranny out of the truck is there any way to check the functionality/serviceability of the governor and solenoid? Is there a bench test procedure?
3. What exactly is different about the input shaft vs. the one I have now? How hard is it to change? Does the whole innards of the trans need to be taken apart?

Bottom line is I'm pretty psyched about my acquisition. I'll know for sure once I get it installed.

everything you need to know about the trans function can be found here .... the input shaft should be the same as any other you might have had, if not you'd need a different clutch, not a different input shaft - the output shaft changed on the Saginaw, and requires a different [fine spline] yoke, listed for 68+

Bill

Note: don't refill it with hypoid gear grease. Fill it with mineral oil or straight 50w oil. Per the info in the documents on Deve's site.

Bill/Charlie;

Hooah. Great info. Thanks.

At this point, based on how it the trans looked on the inside, I think I'll just replace the side plate gasket and refill it. I'll install it and see how it works. I'd rather not get into a rebuild if I don't have to.

The documentation tells how to test the solenoid and the governor.

Charlie;

Roger. I'll read through it all this afternoon. I'll post again once I run some checks on it.

Bill;

Its funny how I read something completely different the third time through. I was confusing the front yoke with the input shaft. The front yoke is what hooks the drive shaft to the output shaft right?

If so, can I just pick up a new one at my FLAPS?

yes, the slip yoke [not 'front yoke'] is at the back of the trans, an internally toothed tube that slides onto the trans output shaft and has the U-joint on the back end - not sure the FLAPS will have them, I've always picked them up at a wrecker and put new U-joints on them

Bill

Bill;

So am I looking for any Chevy truck after 1968? Do junkyards usually sell the yokes or do you have to buy the whole drive shaft?

yes, after 68, ask for the fine spline slip yoke, I think it's 26 0r 27 teeth, count the output shaft on what you have, the earlier type is courser, about half as many teeth ... it'll depend on the yard I suppose, but I've always been able to split the U-joint and just take the yoke off

Bill;

Hooah. Got it.

Ok, one more round of questions:

1. Does anyone have a source/part number for a gasket set for this trans? I pulled the side cover off an kind of jacked up the gasket. I just don't want to spend half an hour in the FLAPS with some kid giving me the trout look from behind the counter.

2. Can I hand activate the kick down switch? I looked all over the carb on my 78 250. I couldn't find any way to get the switch mounted on the carb using the little bracket that came with it. I had the thought that if the switch is activated when I stomp on the gas, why can't I just punch it by hand. I temp mounted it in the dash using one of the knob wholes from the radio I pulled out. I'm thinking that when I want to shift down out of overdrive I could just reach over and press the switch.

3. With an HEI distributor on the motor, how do I wire the ignition ground circuit. According the to manual the circuit is required to temporarily kill the ignition when you stomp the gas and activate the kick down switch. Is that function absolutely necessary and if so, how can I wire it into my HEI distributor?

4. Can I just pull the shifting rods from a 67-72 column shifted truck instead of trying to fabricate/modify the ones I have? I don't have any metal fabrication skills or equipment so I'd rather avoid any fab requirements.

I temp installed the pull cable and the wiring for the trans over the weekend. I spend a while redoing some splicing that had been done. I pulled all the electrical tape off and soldered and heat-shrinked the joints. Friday is a training holiday so I plan on hitting a local junk yard to pick up the fine spline yoke I need and hopefully some new shifting arms.

I'm so close I can taste it. This is exciting.

I can answer 1 and 2 for you for sure. Napa should be able to get the gasket set for the main trans, perhaps even for the complete trans and overdrive unit.
For the second, while you could manually hit the kickdown, a more convenient solution might be to use a floor mounted kickdown switch, like shown here about 2/3 way down the page.

Bill;

The floor mounted switch sounds like a good idea. I'll have to dig around and see if there is a hole I can use. I'll try to get to Napa tomorrow to see if they have the gasket set.

Its a good thing I got the relay, governor and solenoid with the trans. Did you see the prices on that website? OMG!!

1. I found gaskets and a rebuild kit on the web but don't remember the source.

2. That will work. I hand switch mine with a toggle switch.

3. Attach the ground wire to the distributor side of the coil if you have a separate coil. If it's inside the dist. I don't know how.

4. Can't help you there.

Charlie;

Thanks for the info. I assume you used on of the "older" overdrive transmissions (4 bolt cover) so you didn't have to deal with the shifting arms issue.


After more late night research I found an instructions sheet that said you could hook the kick down switch to the negative terminal on the distributor if you don't have an ignition coil. I'll check that out this afternoon.

The other realization I had was that the side cover is on the trans and not the overdrive so it should be common to all that series of transmissions and therefore be relatively easy to find.

I'm getting closer all the time!

One more related question.

I want to put a new clutch in while I'm swapping the trans. I'm not sure what to ask for. I have a 58 Suburban with a 78 250 and I'm trying to install a 67 3 speed overdrive trans. How do I ask for a new clutch??

You could have anything from a 10" to a 12" clutch depending on what flywheel/bell housing combination you have with that engine. It's best to remove it and determine what it is. Also match up the release bearing. It will save you untold misery.
Fred

Yes, mine is a 4 bolt cover and I had different issues with it. I had to use the cover for an AD truck.

Fred;

Thanks. I'll pull the old clutch off when I drop the trans and take it with me to the FLAPS. I'll take the release bearing as well.

I was just wondering what the deciding factor was when selecting a clutch (engine, trans etc.)

I picked up a gasket kit at NAPA last night. I'll replace the side cover gasket this afternoon. I'll save the other gaskets until I ever decide to rebuild the transmission.

There is a junkyard that focusses on older vehicles near hear. I'm heading out there tomorrow to look for a drive shaft yoke and shifting rods.

Wish me luck!!

Update:

I picked up a yolk at the junk yard. I couldn't find the shifting rods I needed. I actually made the originals work with a little ingenuity. I got the old trans out and the new one in. I went to the hardware store and got stuff to make a block and tackle. I rigged up a brace inside the cab and ran the line down through the hole in the floor. That allowed me to lift the trans from under the truck. I had one of my boys hold the end of the line while I muscled the trans in place. I got the linkage hooked up, connected the wiring and the lockout cable. All I have to do is wire in the hot wire to the relay and the ignition ground wire to the distributor.

I just realized that I forgot to put the new gasket on the side plate. I guess I'll check it frequently for leaks and replace the gasket if the old one starts to leak.

I dropped the gas tank while I was under the truck with the drive shaft off. I used the same line from the block and tackle and was able to cradle the tank while I lowered it down. I took out the sender unit and it was acting crazy. Sometimes it would settle down and give a decent reading (3-30 ohms). Most of the time it jumped all over and spiked the multi-meter. I'll try to pick up a replacement and reinstall it.

Now for the questions.

Is there a secret to installing u-joints. No matter what I did I kept getting one of the needle bearings down in the end of the cap. I pretty much destroyed my u-joint after trying to install it 3 times. Help!!!

Finally, is there supposed to be a trans cross member in my 58 Suburban? The new trans has a lot more weight hanging on the end of the trans. I'm concerned that the trans housing may not be strong enough. I don't see any evidence that there ever was a trans crossmember. Just wondering if the later trucks that had the overdrive transmissions had one.

This is exhausting work!!!

none of the standard shift trans used a cross member under them, don't worry, it's the bell housing that takes the weight ... for assembling the U-joint, if you're trying to do it under the truck, pull it right out and do it on the bench, grease the needles enough they stay put standing in the cups, just move gently and deliberately and you'll get it

Bill

Use thick grease, you could chill it and maybe even the caps in a freezer before trying to install them, have the spider part real clean with no grease on it, make sure the holes are burr free etc.

Gentlemen;

Thanks for the tips. I'm off to classic parts to look for a fuel sender and some firewall hole covers.

By the way, I'm really sore!!

I hope to have it running this afternoon.

Hey Larry,
How about some pictures of the shift linkage, I'd like to see how you did that.

Thanks,
Tommy

Tommy;

It's not pretty but I'll take a picture once I confirm that it works.

My final question remains how to wire the throttle kick down swith into the HEI distributor. There are 5 wire hookups on my Delco Remmy distributor.

1 - Battery
2- Tach
3. Pos
4. Neg
5. Ground

The manual says to hook it to the negative terminal on the ignition coil. I don't have an ignition coil and I don't want to fry something in my distributor. Where do I hook that wire?

Also, can the vehicle be driven without that wire hooked up? Can I just let off on the gas when I hit the kickdown switch and accomplish the same thing? I'd like to test drive this later today.

Update;

I got the fuel tank put back together and installed in the truck. Getting back in was a lot harder than I anticipated. I thought I had a great plan of using the creeper to move the tank and then using wood blocks at each end of the tank to build it up to the correct height. The concept generally worked but was a lot more of a pain than I thought it was going to be. If I ever have to drop the tank again, I'll need to come up with a better method.

On a happy note, I got the fuel guage working. I pulled the old sender out and tested it with the multimeter. It jumped around a bit but would eventually settle on a correct number. The gasket between the sender and the tank was all cobbed together and had a bunch of RTV-like sealant on it. I cleaned all that off and pirated a good gasket from another sender that I had. The float was pretty ratty and I think it had a leak. I also pirated the float off my other sender and used that. With a good clean up around the lip of the tank I screwed the sender in place and mounted the tank. When I turn on the key it jumps right to a half tank which is the correct reading. Finally!!!!

With all the messing around with the fuel system, I also discovered I had a leaky fuel pump. No wonder there was always a faint fuel smell in the cab. I picked up a replacement at NAPA and installed it when I finished with the tank. The truck started right up and ran like a champ. There must have been enough fuel in the carb bowl to keep it running while the new pump drew fuel into the lines.

I've been doing a bunch of research about hooking the kickdown to the HEI distributor. Everything I've been able to find says not to bother trying to hook up the kickdown to an HEI. I have the kickdown switch mounted on the dash. When I want to kick down the trans I'll push the button and just let off the gas for a second. I think that will do the trick. If anyone has any experience with this, please post the details.

If I can get the wiring buttoned up, I'll be taking it for a spin tomorrow afternoon.

If it didn't need to kill the engine for that split second they wouldn't have put that feature in. I'm sure it would work without it, but for how long?

An OD will not kick out of overdrive with a load on it. The kick down switch kills the engine momentarily to allow it to shift out of OD.
As long as you do not want it to kick down like a passing gear when you floor it then the switch is unnecessary.
All that is necessary to operate an OD completely satisfactorily by someone how understands mechanical things is the cable and a toggle switch. Then when you want to bring it out of OD all you do is turn the switch off and let up on the gas for a split second.

Finally after much effort, I got the transmission installed and operational. The junk yard drive shaft yoke that I picked up had evidently been sitting out in the weather for a while and was rusted about halfway in. No matter how hard I tried I couldn't get it all the way on the tail shaft. Well after about 1-2 hours with a file and hacksaw blade I managed to clean up the inside enough that it would go on the tail shaft. Still took some persuading but I go it on.

The U-joints were just as frustrating. Whoever suggested to put the caps in the freezer is a genius. After about 15 minutes in the freezer I could literally push them in by hand. No more pounding with the ball peen hammer. I'm definitely going to remember that trick.

I took it out for a test drive and it works great. I got up to about 70mph (according to the GPS) at around 2600rpm. Before the overdrive I was at 3000rpm at 55mph. The governor works properly. It won't shift into overdrive in 1st gear. When you shift into 2nd it goes into 2nd "under." Rev it up to speed let off on the gas and it jumps into 2nd over. The only issue I have found is that when you shift from 2nd into 3rd gear it goes straight into 3rd over. I don't get 3rd under unless I use the kickdown switch to drop it down. I thought it was supposed to drop down automatically when you shift up to another gear.

Dave/Charlie;

Is this tracking with your experience? How do you drive yours??

I figured out the kickdown switch operation. It will take a little getting used to. I just push the button on the dash (I couldn't figure out how to carb mount the kickdown switch) and let up on the gas. It hesitates for a second and then starts do drive in the lower gear. I just need some practice so I don't try to ram it into gear.

The only remaining issue, aside from reinstalling the trans cover and rubber mat, is to figure out the linkage. My home-grown fix isn't working on the 1st/Reverse side. It goes into reverse with no issues but won't drop into 1st. I think I either need to figure out how to lengthen the shift rod or see if there is anymore adjusment left on the column. I'm afraid I'll get it to go into 1st but then lose reverse. I'll keep you posted once I figure it out.

Overall I'm very happy with the results. The issues with the fuel tank and u-joints made it a lot harder than I anticipated, but I feel like I've made a significant accomplishment. I'll post again once I drive it a little bit and figure out the shifting procedures.

"I took it out for a test drive and it works great. I got up to about 70mph (according to the GPS) at around 2600rpm. Before the overdrive I was at 3000rpm at 55mph. The governor works properly. It won't shift into overdrive in 1st gear. When you shift into 2nd it goes into 2nd "under." Rev it up to speed let off on the gas and it jumps into 2nd over. The only issue I have found is that when you shift from 2nd into 3rd gear it goes straight into 3rd over. I don't get 3rd under unless I use the kickdown switch to drop it down. I thought it was supposed to drop down automatically when you shift up to another gear."

And this is the exact reason that I use a switch to go to third under for almost 15 years on a daily driver only vehicle 3sp+od. Second gear, second over, switch, third gear, switch, third over. The switch idea was offered to me by a good friend, Jack Halton. When you have one of these you understand perfectly how the 'kickdown' doesn't make sense...You are thinking to yourself..."I'm flooring it to hit a switch to do what? I'm going from 2nd over to third over, I want to go into third!?!?!?!?" I use a relay and use my push-pull switch in the choke location (have an elec. choke).

Congrats on your find and installation.

Regards,

Cosmo