D20 Speedometer cable oil leak

[mriplaybass]

It's too hot today to go on an exploring mission, so I will ask a question from the cool comfort of the house.
The CJ is ready to head for Colorado next month, and all the remains is a few tweaks. I have had an oil leak from the Transfer Case which is dripping from around the drain plug. Upon further investigation, I can see that the actual oil leak is where the speedometer cable attaches to the Transfer Case tail shaft. Though I have had Dana 20 's torn down, I don't remember ever removing the speedo drive. Is there a seal or an O ring in there? If so, who carries it? The breather is clear, and the oil level is just below the fill plug.

 

[Posi]

With the breather clear I'm surprised it's leaking from the driven gear being high in the case.

The 20 never came with an o-ring, I believe it was a gasket. The last 20 I rebuilt didn't have one, they don't show it in the exploded view as well. However, there was a driven gear gasket in the bronco 20s but I'm sure you would have to buy the whole driven gear to get the gasket, if its still available, not a good option.

Thinking Right Stuff, or Ultra black

 

[Hedgehog]

Use thread sealer like pipe dope but for automotive use. Can't hurt and is cheap enough. You might just need to reach in there with a wrench and snug her down some.

 

[mriplaybass]

I will double check the oil level. I actually removed the guts in the breather and attached a hose that terminates behind the battery, so going through deep water would not be a problem. I can blow through the hose with no problem.
New rear shocks came today, so maybe while I'm under there installing the shocks, I'll pull the speedometer cable and look. I guess pipe dope or silicone is a good alternative. The leak does get worse the longer we drive, and the warmer it is outside, so I can't rule out the possibility of an over fill, even though I am always careful about oil levels.

I'm used to"Chip" marking his territory in the driveway, but this is a bit much.

 

[hagar]

If your driven gear has reverse spirals on the shaft, then trying to put an o-ring up inside the threaded nut and/or sealing the threads may be your only option.
If your driven gear shaft is smooth, then there is an adapter that is machined for and has a small seal installed on the gear shaft side of the adapter.
The seal will not work with the spiral shaft gears. They tear up the seal.
I have a whole bunch of the machined threaded speedometer cable adapters and seals and can make them available for those that want to try them.

 

[Hedgehog]

Bass - I don't want to be misunderstood. The speedometer mechanism is threaded into the case. If it is leaking around the base of the speedometer drive unit the drive unit might just be loose needing a simple tightening. I'm not talking about plumbing pipe dope, Lock-tite makes a thread sealer for automobiles that goes on the threads just like the plumbers stuff does. Rob at Willys Works uses it on ALL threads that punch through inside the Transmission and Transfer Case . he thinks many leaks would never happen if this simple percussion were taken during a rebuild.

You aren't getting over flow from your breather tube are you? If so that's a lot of pressure. Dribbling from the speedometer drive wouldn't be a surprise. The fluid in a Transfer Case moves around getting into all the nooks and crannies.

It sounds like hagar knows what he's talking about.

 

[mstar]

If your driven gear has reverse spirals on the shaft, then trying to put an o-ring up inside the threaded nut and/or sealing the threads may be your only option.
If your driven gear shaft is smooth, then there is an adapter that is machined for and has a small seal installed on the gear shaft side of the adapter.
The seal will not work with the spiral shaft gears. They tear up the seal.
I have a whole bunch of the machined threaded speedometer cable adapters and seals and can make them available for those that want to try them.

I have done the fix you describe with a small seal inside the housing.My shaft had the spiral grooves so I brazed the up and then turned it down smooth on the lathe. Works like a champ. No more leaks. This is on a D 18 btw

 

[mriplaybass]

If your driven gear has reverse spirals on the shaft, then trying to put an o-ring up inside the threaded nut and/or sealing the threads may be your only option.
If your driven gear shaft is smooth, then there is an adapter that is machined for and has a small seal installed on the gear shaft side of the adapter.
The seal will not work with the spiral shaft gears. They tear up the seal.
I have a whole bunch of the machined threaded speedometer cable adapters and seals and can make them available for those that want to try them.

No spirals on the shaft, so I put an O ring on it. I also put an O ring on the shaft housing. It actually looks like there is supposed to be one there. So far, no leaks. But now I can see that the rear driveshaft seal may be leaking! .
But that too may have to wait. Our 02 F350 just threw a code, and is running like . Have to take care of that first since we need it to haul the CJ to Colorado in just 12 days!

 

[Lumpy Grits]

Ck the oil level in that t'case. Have you confirmed that the t'case breather is clear?
LG

 

[mriplaybass]

Breather is clear, and I know that the oil level is a little low. I will be adding oil before we drive it anymore.

 

[Lumpy Grits]

I was think'n it may be overfilled from the tranny.
LG

 

[Hedgehog]

The T-18 and Dana 20 don't share oil as the T-15 and Dana 20 did.

 

[Lumpy Grits]

Looks like my CRS is in 'bloom' again.
LG