Speedo Cable Leak

[67step100]

My speedo cable is leaking transmission fluid where it enters the transmission. Between my parts book and my research here it looks like I should be replacing 2 seals. Rock Auto does not have any of these pinion seals in stock. Does anyone know where else I could get them or if they are just O-rings, what size they are? Thanks.

Also, is there a drain plug for the transmission fluid? And what do you recommend for transmission fluid? It's an A727, 1969.

[martincom]

They're not seals, but O-rings. A small one that is within the bore of the range selector and a large one for the outer diameter. I don't recall the size, but NAPA, O'Reilly, Advance will likely list them.

No drain plug on the stock pan. There is no need to drain the transmission to pull the range selector/speedo pinion. Just lift the rear of the truck and leave the front on the ground. The fluid will flow out of the tailshaft housing to the front of the transmission.

[67step100]

They're not seals, but O-rings. A small one that is within the bore of the range selector and a large one for the outer diameter. I don't recall the size, but NAPA, O'Reilly, Advance will likely list them.

No drain plug on the stock pan. There is no need to drain the transmission to pull the range selector/speedo pinion. Just lift the rear of the truck and leave the front on the ground. The fluid will flow out of the tailshaft housing to the front of the transmission.

Thanks. That is great. I will check with Napa. I assume there is some sort of spring clip or circlip holding the pinion in place, or do I not need to remove that?

I want to change the pan gasket (and filter while I'm in there) as well as I also have a small leak from the pan. Hence my question about what transmission fluid to use.

[martincom]

There is a horseshoe style clamp that holds the range selector into the tailshaft housing. It is secured by a single bolt, visible in your photo, just forward of the speedo cable. It takes a good tug to pull the range selector out, due to the O-ring. There is nothing additional holding the pinon into the range selector. The pinion will come out with the range selector and then can be pulled out of it.

As far as transmission fluid, ATF +4 would be the latest recommendation. It is rather pricey stuff. So if you're just adding to what is likely not ATF +4, I would utilize what I had, such as Dexron I, II, or III. Back in the day, we utilized Type F (Ford) in our muscle cars. It had a bit more friction to it. So, in theory, the clutch pack/bands would grab quicker.

As pricey as ATF is, I'd catch it in a clean, big, drain pan. I would then re-use it, straining it through a paper funnel filter, typically utilized for paint. Harbor Freight has an excellent price on them and in two different mesh sizes. Any time I drain a fluid that will be re-used I always strain through one of those filters. I even strain latex paint that I utilize in buildings. As once it is open, there is clumps of skinned paint in it.

Of course, if the fluid is burnt (brown color) you've got bigger problems.

If you opt to change it all, be sure to drain the torque converter. You'll have to turn the ring gear with a large screwdriver until the drain plug is at the bottom of the splash shield opening. If I remember correctly, torqueflites have a 9 quart capacity.

You may want to give some thought to add a part throttle kickdown kit to the valve body. It is simple to do once you have the pan off. The pre-1971(?) torquflites do not downshift until you come to a complete stop. You really notice this when rolling up to a yield sign and then accelerate. Your speed is down to 10 or 15 mph and your accelerating slowly---in third gear. A part throttle kickdown kit will yield a 3-2 downshift in those situations.

I add this to every torqueflite I've owned that didn't have it, including my '71 D100 last summer. Mopar use to offer the kit through their Direct Connection performance parts, but I'm gathering that went away with the Fiat ownership. The kits I purchased last summer I sourced from Torqueflite Patty: tflitepatty@comcast.net They were $129. He also has the stamped steel Mopar 2-1/4 deep pans, w/drain plug. I added one of those to my D100, as well. Often, the stock pan has been off and over tightened a number of times where it is difficult to get them so they don't leak.

[67step100]

There is a horseshoe style clamp that holds the range selector into the tailshaft housing. It is secured by a single bolt, visible in your photo, just forward of the speedo cable. It takes a good tug to pull the range selector out, due to the O-ring. There is nothing additional holding the pinon into the range selector. The pinion will come out with the range selector and then can be pulled out of it.

As far as transmission fluid, ATF +4 would be the latest recommendation. It is rather pricey stuff. So if you're just adding to what is likely not ATF +4, I would utilize what I had, such as Dexron I, II, or III. Back in the day, we utilized Type F (Ford) in our muscle cars. It had a bit more friction to it. So, in theory, the clutch pack/bands would grab quicker.

As pricey as ATF is, I'd catch it in a clean, big, drain pan. I would then re-use it, straining it through a paper funnel filter, typically utilized for paint. Harbor Freight has an excellent price on them and in two different mesh sizes. Any time I drain a fluid that will be re-used I always strain through one of those filters. I even strain latex paint that I utilize in buildings. As once it is open, there is clumps of skinned paint in it.

Of course, if the fluid is burnt (brown color) you've got bigger problems.

If you opt to change it all, be sure to drain the torque converter. You'll have to turn the ring gear with a large screwdriver until the drain plug is at the bottom of the splash shield opening. If I remember correctly, torqueflites have a 9 quart capacity.

You may want to give some thought to add a part throttle kickdown kit to the valve body. It is simple to do once you have the pan off. The pre-1971(?) torquflites do not downshift until you come to a complete stop. You really notice this when rolling up to a yield sign and then accelerate. Your speed is down to 10 or 15 mph and your accelerating slowly---in third gear. A part throttle kickdown kit will yield a 3-2 downshift in those situations.

I add this to every torqueflite I've owned that didn't have it, including my '71 D100 last summer. Mopar use to offer the kit through their Direct Connection performance parts, but I'm gathering that went away with the Fiat ownership. The kits I purchased last summer I sourced from Torqueflite Patty: tflitepatty@comcast.net They were $129. He also has the stamped steel Mopar 2-1/4 deep pans, w/drain plug. I added one of those to my D100, as well. Often, the stock pan has been off and over tightened a number of times where it is difficult to get them so they don't leak.

Thanks. Great info.

[67step100]

I know the truck must be running and warmed up when checking the trans oil level. The dip stick says right on it to check the level when the truck is in neutral. Does it matter if the truck is in park or neutral when checking the level?

[martincom]

No, park or neutral is fine. The transmission fluid will expand as it warms. So you actually want to drive it to warm it fully. So you want to start with it below the add mark. It'll expand quite a bit.

[67step100]

No, park or neutral is fine. The transmission fluid will expand as it warms. So you actually want to drive it to warm it fully. So you want to start with it below the add mark. It'll expand quite a bit.

Thanks. Had to add half a quart after the drive to top up. And no leaks so far (knock on wood).