Oil Leak

[Chuck W.]

I have a pesky oil leak on my 1964 CJ3B, it looks like it is leaking oil where the speedometer connects to the transfer case. I took the cable off, and it appears to be leaking oil around the drive gear. I have looked through all my manuals and catalogs and I don't see any type of seal or O-ring listed. Any ideas to stop this drip?

[YLG80]

I have a pesky oil leak on my 1964 CJ3B, it looks like it is leaking oil where the speedometer connects to the transfer case. I took the cable off, and it appears to be leaking oil around the drive gear. I have looked through all my manuals and catalogs and I don't see any type of seal or O-ring listed. Any ideas to stop this drip?

Hello,
This could be interesting to read .
viewtopic.php?t=238779
Yves

[Chuck W.]

Yes, Thanks!

This replacement cable had a little rubber seal between the cable housing and the flat boss on the TC.

I am a little confused as to where he put the rubber washer he made, between the cable and the gear sleeve or between the gear sleeve and the TC output shaft housing?
One good comment in that post concerned a plugged TC breather, I cleaned mine while the body tub was off, but I'm going to check it again. I am also considering machining a groove in the gear sleeve for an O-ring.

[YLG80]

Yes, Thanks!

This replacement cable had a little rubber seal between the cable housing and the flat boss on the TC.

I am a little confused as to where he put the rubber washer he made, between the cable and the gear sleeve or between the gear sleeve and the TC output shaft housing?
One good comment in that post concerned a plugged TC breather, I cleaned mine while the body tub was off, but I'm going to check it again. I am also considering machining a groove in the gear sleeve for an O-ring.

It seems that some cable connectors are equipped with a rubber gasket like on that picture.
This one comes from Kaiserwillys.

Yves

[Wolfman]

Is the vent on top of the front transfercase housing plugged ??
When the T-case gets hot, this condition pressurizes the T-case. Causes leakage problems.
In one instance, oil was pushed all the way up the speedo cable and there was oil inside the speedometer. A puddle behind the glass.

[Bruce W]

Yves,
That cable is for M38 and/or M38A1. The seal is there not to keep oil in, but to keep water out.
BW

[YLG80]

Yves,
That cable is for M38 and/or M38A1. The seal is there not to keep oil in, but to keep water out.
BW

Thanks Bruce.
But Kaiserwillys shows that cable for the CJ-3B up to the 57-64 FC-170 jeep

Speedometer Cable Assembly 60"
Fits 41-71 MB, GPW, CJ-2A, 3A, 3B, 5, Commando, FC-150, FC-170

Anyway, Mike comment here above is really made of gold !+
Yves

[Bruce W]

DO NOT use Kaiser-Willys’ catalogue as a reference source for data pertaining to parts interchange or correct application. Yes it will “fit” all those vehicles, but it is not correct for most of them. Plus, that’s an expensive cable and the extra cost is not justified for a vehicle that doesn’t need to be waterproof. There is something causing the leak in question and using this sealed cable would only result in, as has been said, the speedometer head full of oil.
BW

[Chuck W.]

I pulled the breather off the top of the TC, it looked OK, but I took it apart and gave it a good cleaning anyway. I also pulled the speedometer drive gear out, gave it and the sleeve a good cleaning and inspection; everything looked brand new. I dropped the oil out of the transmission and TC, actually let it sit for a couple of days to drain completely. I put the drain plug in the transmission and filled it with oil. I had left the drain plug out of the TC, and almost immediately, oil started dripping out of the drain hole. I went ahead and put the plug in and filled the TC with oil, but now I am thinking the TC was overfull. Does the oil in the transmission and TC equalize?

[Wolfman]

May need a little back up.
I am not that familiar with a CJ-3B but I am thinking there is a hole added at the back of the T-90 transmission case, at the fill plug level, that allows excess oil in the transmission to drain into the transfercase.
??? This is a manual transmission and not automatic ???
This was a method of solving an oil transfer problem experienced by the earlier T-84 transmission and transfercase.
On the earlier units, a common problem was oil transferring from the transfercase into the transmission, overfilling the transmission. This condition could lead to oil leaking out the front bearing retainer tube and get on the clutch.
The drain hole on the later T-90 would not effect the tranfercase oil level unless the transmission was over filled.
???
What weight oil is in the transfercase ?
Used to be 80w/90.
Not sure on a CJ-3B.
Where I am headed with this.
I work on a lot of older farm tractors that used 80w/90 gear oil in the transmission and rear differential.
The farmers would change the rear end oil and instead of using 80w/90 gear oil, would go to the local tractor supply store and buy transmission/differential fluid. This fluid also doubled as hydraulic oil and was a much lighter weight.
The tractor that was pretty much leak free would start leaking oil out of every seal on the differential.
No seal on the speedo gear retainer. Just the heavy oil to do the sealing.

[Chuck W.]

It's a 1964 CJ3B with a T-90/D18. I am using a non-hypoid 90wt mineral oil. I did notice that the oil did not start dripping out of the TC drain until the transmission oil had reached the fill plug level. I'm going to let it sit for a few days and recheck the levels and see what they look like. I guess this might be one of those leaks that I will just have to live with.

[Wolfman]

???
The oil did not start dripping out of the drain plug hole until the oil level was up to the fill plug hole level ???
That does not compute ?
Is it possible the TC oil pan is on backwards ?
Oil drain at the top instead of the bottom ?
Not even sure this is possible, but that statement does not make any sense.
With the drain plug removed, the oil should come out as soon as oil is put into the fill hole.
The drain plug should be at the lowest point.

[Chuck W.]

With the DRAIN and FILL plugs OUT of the TRANSFER CASE, I installed the DRAIN PLUG into the TRANSMISSION and filled it to the full level. Oil started DRIPPING OUT OF THE TRANSFER CASE DRAIN HOLE.
I posted this same question on the CJ3B board and was told that there is a passage from the transmission to the transfer case at the transmission normal full line, So it would appear that this is normal, which is exactly what you said in your post above.
Here's Bob W.'s reply on the CJ3B forum:

The normal transfer case fluid level is lower than the transmission fluid level. When the vehicle is driven forward, oil in the transfer case flies off the spinning gears into a cast slot in the transfer case and through a drilled hole where it enters the transmission. So, when driving down the road oil is constantly being "pumped" from the transfer case into the transmission. There is another drilled hole between the gearboxes at the transmission normal oil level. When the transfer case pumps enough oil into the transmission that it is "full" any additional oil drains by gravity back into the transfer case.

[Wolfman]

Thank's for posting Bob W's comment.
The drain hole between the T-90 transmission & the T-case was not just my imagination.
I have considered making a drain hole in a T-84 but never got around to looking into the mod.
Not sure it would be possible.
Would solve the oil transfer problem on early jeeps.

[Chuck W.]

I don't know if I fixed the leak or not, I took the speedo drive gear out and cleaned everything. The spiral groove in the shaft that I think is suppose to move any oil back to the case was filled with grunge, so I gave it a good cleaning and put it all back together. Transmission and transfer case are both filled to the bottom of the fill plugs, but I haven't had a chance to run it yet. No drips sitting still, we will see.