what gear oil to use in 3 speed

[n1gzd_plymouth]

I have 36 Plymouth 3 speed.

my 34-36 manual says to use SAE 160.

my 36-42 manual says to use SAE 90.

I used NAPA SAE 90 fluid gear oil. It was a lot runnier than I was expecting.

Am I using the recommended stuff?

Also, I am trying to figure out where my huge transmission leak is coming from.

Most of it seems to be coming from the right side. It seems to be squirting all over the place (including above). My speedo cable is not currently connected. Could oil be coming out of the speedo drive? I would not think so but I don't remember noticing the leak until I installed the speedo drive. (but not the cable which is going in soon).

Rebecca

[JIPJOBXX]

Did you put a gasket in between the tranmission and the bell housing? It an easy mistake to make and alot of people have done this in the past.

[n1gzd_plymouth]

I did not install it (trying to get bugs out of what previous owner did).

If this was the problem then I would think that the source of the leak would appear to be in that location. It is not obvious where it is coming from but it seems to be more the right side and it is getting on the bottom of the floor (not just dripping down it seems to be quirting).

Rebecca

[Jim Saraceno]

have 36 Plymouth 3 speed.

my 34-36 manual says to use SAE 160.

my 36-42 manual says to use SAE 90.

My '35 manual says 160 in the summer and 90 in the winter.

I just looked at the tranny I have sitting in the basement and oil definitly goes into the area that the speedo is connected but I couldn't tell if that area should be opened or closed to the outside. I'd definitely try putting the cable in and see if that takes care of it.

Could it be coming out the rear seal and being slung around by the e-brake drum?

I know there are a number of gaskets and seals in the unit, have you taken something apart or has this problem just cropped up on it's own. The MOTORS manual has a nice exploded view of the transmission that might help you out. PM me if you need a copy.

[n1gzd_plymouth]

ok. I will try 160. I don't think that I have even seen 160 fluid gear oil in the auto parts store.

Rebecca

[Normspeed]

I've seen 140 gear oil at NAPA and O Reilly's in my area.

I installed a P15 3 speed in my P24 while I rebuilt mine. The speedometer cable would not reach the P15 drive, so I just capped it with a rubber crutch tip. That might cure your leak until you can install the cable.

[n1gzd_plymouth]

I can install the cable ASAP (just got it in the mail). However I have no idea if a disconnected cable can cause an oil leak (I did not notice any leaks before I installed the drive gear). In other words, with just a gaping hole there I did not notice a leak, but if I installed the drive gear then I noticed big leak. this might have been a coincidence. After I install the cable I will find out.

I am suspecting that really I have a bad seal and it was a coincidence.

Rebecca

[Normspeed]

There is a seal that goes in the drive. I think with the gear drive in there and no cable, it might sling a bit of oil. Seems like there's not much else in that area that might actually throw oil onto the undercarriage. But I'm not well versed in the 36 Plymouth either.

[greg g]

get the oil from Tractor supply company it is bronze metal safe. Some of the additives for Hypoid gears earning the oil the EP rating, are corrosive to the bonze in synchros.

Edited September 29, 2009 by greg g

[n1gzd_plymouth]

There is a seal that goes in the drive. I think with the gear drive in there and no cable, it might sling a bit of oil. Seems like there's not much else in that area that might actually throw oil onto the undercarriage. But I'm not well versed in the 36 Plymouth either.

Hm, I don't remember seeing any seal. I just stuck the gear houseing into the hole and screwed it in. If it does not rain this weekend I will find out more.

thanks,

Rebecca

[Normspeed]

Rebecca, this might not be the same as your 36, but I happened across this photo posted by Jim Yergin. The speedo gear retainer on my 53 is the same. In the bottom of the drive retainer you can see a rubber seal. It seals around the shaft of the speedo gear, in the metal area on the gear in the photo. It's constructed with a metal outer and a rubber inner seal surface and is pressed into the retainer. (The gear in the photo is upside down in relation to the drive retainer)

When I rebuilt my trans, the old seal was bad. I believe I found a small fat O-ring to fit in there. Later, I purchased the correct seal from Neil Riddle, but after many miles the O-ring is not leaking so I never installed the correct seal.

[n1gzd_plymouth]

yes. that looks exactly like what I have and the seal looks the same.

I don't know if it is the source of my leak but it is suspect. I will look for an 0-ring that can be substituted for it. Thanks for the tip.

Roberts motorparts has also suggested that my rear main tranny seal could be the problem. I did not think that the ebrake looked oily so I am not sure if that was it but he did say that this type of leak would cause oil to spray upwards (which I am seeing).

I will probably change it anyway.

thanks,

Rebecca

[Jim Yergin]

Rebecca, this might not be the same as your 36, but I happened across this photo posted by Jim Yergin.

Norm,

I believe that is actually a picture of what Rebecca has. I sent her those parts because she was missing them.

Jim Yergin

[n1gzd_plymouth]

Norm,

I believe that is actually a picture of what Rebecca has. I sent her those parts because she was missing them.

Jim Yergin

Yes thank you thank you thank you. I have not yet proven that my leak is coming from here but it is a substantial leak that appears to be spraying oil all over the place. My drum brake is pretty dry so I was thinking that the tranny rear main is not the cause. last weekend was too wet to do any investigation. I hope to solve it this weekend.

Rebecca

[Desotodav]

I love trawling through these old posts to rectify my current problems.

I have tried numerous times to fix an oil leak coming from the speedo cable connector area on the right-side rear of my 52 truck (3 speed) gearbox - but today I believe that I have cured the problem!

I removed the 'sleeve 21-85-76' so that I was able to get to the 'oil seal 21-85-56'. I dropped down to the local seal shop and collected a thing that the fella called a 'rotary seal' which was almost a perfect match for the original seal. I returned home and installed the 'pinion 21-85-5' along with the other parts and found that the seal created a nice tight fit on the shaft of the pinion. The old seal had gone hard over the past 60 years and fitted quite loosely on the shaft of the pinion.

I can't wait to get the truck out of the garage now as I think that I am down to only 1 oil leak to fix now (front timing chain cover). Photos to follow for those that are interested...

Desotodav

[greg g]

any thing newer than GL 3 rating is not recommended for gearboxes with white metal ( bronze, brass, etc) usually used in older synchronizing assemblies. The newer hypoid type oils are not white metal friendly and will have a negative impact on those pieces.

The viscosity is not a real problem as long as the recommended vis number is covered by the products range.

When I was looking around for fluid for my trans, I finally found some Castrol gl2 on the shelf at one of our local (non National) auto parts stores.