Leaky TiDi [rhymes w/ tiki] transmission

[Adam58]

Okay, my YB is leaking transmission oil at an alarming rate - even for an LBC! It appears to be coming from the drain plug but I suspect it can fool me by leaking higher and following down. It's a TD transmission. My questions are:

1. Do they ever leak from the drainplug?
2. Is the rear sear the most likley (and if not, what is?)
3. Can the rear seal be done in the car? Any tricks?
4. What is the exact size of the fill and drain plugs across flats? They are soft brass and I don't want to [mess] them up.
5. What should I refill it with in So. Cal? 80W/90 hypoid?

I'll jack it up and really check it out when I get in the mood but I'd like to know exactly what I'm looking for when I do.

Thanks! Adam

 

[Steve_S]

The drain plug is whitworth but I forget the correct size. I can loan you a socket if needed but you may as well buy one at some point. It's possible that the drain plug is leaking. The way to tell would be to clean it up well and then take an easy drive around the neighborhood. After a low speed drive the oil path should be obvious.

A lot of oil could mean the rear plug let loose or is leaking but you would see it coming from the split pin hole. I have that problem in my YB currently but I've managed to put it off so far.

By rear seal do you mean the transmission flange seal? You should be able to do that in-car but I haven't done it on my YB yet so I can't say positively. Do you have a Y-Type repair manual? If not they pop up on eBay from time to time for around $60. I have one here if you need anything specific.

The factory calls for 140W gear oil and that's what you should use. Some people have switched to synthetic (such as redline MT-90) with mixed results. Make sure that whatever you use is safe for bronze and other soft metals.

 

[David_DuBois]

Jees, whith 3/4 of Southern California on fire (or so it seems), I'm not sure that I would want to drive around and leave an oil trail to my garage - the fire might just follow you home. Adam, you have an e-mail with several charts reering to the fasteners used in the XPAG engine and else where. I will follow this up with a measurement of the transmission plug head size.
Cheers,

 

[David_DuBois]

Ok, I'm back. The drain plug head is 1/2" Whitworth, which has an across the flats measurement of 0.920. Before you get too carried away with the transmission, the oil could be coming from the engine. Anywhere from the rocker cover to the rear main seal or the welsh plug at the back of the cam shaft (leaks from the latter two places will be coming out of the hole in the bottom of the bell housing where the split pin peaks through). Wipe your finger through the leaking oil and smell it. If you gag from the sulfer smell, then it's from the transmission, if not it is from somewhere on the engine.
Cheers,

 

[Adam58]

Good stuff!

I'm pretty sure it's the trans for 4 reasons:
1. It smells like hypoid gear oil
2. It drips directly on the muffler and it's pretty dry up to there.
3. The engine oil is staying topped up
4. The trans oil doesn't even show on the dipstick.

As for the 1/2BSW, I'll buy one. I need to buy BSW/BSF/BA tools anyway and now I have an excuse!

Steve, if you are in town this week, I may borrow yours just to get thing going. Thx for the offer! Per Dave's suggestion, I won't drive it over and risk dragging fire to your place! /bcforum/images/%%GRAEMLIN_URL%%/wink.gif

Dave - thanks for the charts! I'll print them and add them to my garage binder.

Thanks! Adam

 

[Steve_S]

Sounds like you have it figured out already.

You may want to measure your plug. After I posted earlier I went out to see which socket would fit the YB plug. Nothing I have fits properly. It could mean my plug is worn or it could mean the Y-Type gearbox had a different plug than TD. The gearboxes are nearly identical but not entirely, so anything is possible.

Funny, I realized today that I've never changed the gearbox oil in the YB. I've had it since 2003. But I've only put 4,000 miles on the clock since then. For various reasons it gets driven the least, by far, of all the MGs.

 

[vping]

As in the b's would you replace with 20/50?

Jeese, How many miles a year you put on your MG's Steve?

 

[Steve_S]

As in the b's would you replace with 20/50?

Not in a TD, no. 20W/50 in the A, straight 30 in the overdrives and 140W in the TC and YB. The factory knew what they were doing. The only change I would consider would be a modern synthetic oil but so far I have no use for them.

Jeese, How many miles a year you put on your MG's Steve?

I don't own a modern car, so I put all my miles on the MGs. So far this year we've put about 4,000 on the TC, probably 5,000 on the BGT, and 2 or 3,000 each on the C and the A. The YB and B are in the middle of long-term projects so they've seen little to no use this year.

 

[vping]

No modern cars. That's awseome. Can;t do it with kids unless there is a huge MG out there that will fit 5 with luggage, camping gear and the occaisional pooch or 2. Were a big family in a small car hobby world.

 

[Steve_S]

...unless there is a huge MG out there that will fit 5 with luggage, camping gear and the occaisional pooch or 2.

There sure is.

And just to clarify, my wife does have a modern car for herself.

 

[jlaird]

That is outa sight, it's a real car.

 

[Steve_S]

It's big, it's beautiful and it's British!

 

[Scott_Hower]

It's big, it's beautiful and it's British!

Reminds me of a flight attendant in Upper Class on VS17/Heathrow to Newark last Tue. Well, except for the big part /bcforum/images/%%GRAEMLIN_URL%%/jester.gif

 

[Adam58]

Let's see now...

I went out an bought a set of KoKan Whitworth 3/8" drive sockets. They fit well and are finished very nicely and only cost me $50 for 8pcs. (1/8W - 9/16W)

Under the car, the most oily moisture was around the speedo drive. I was able to gently snug the cable collar a little so that may help. I found article by Carl Cederstrand saying that some wicking and dripping from there is normal.

The rear seal area was almost bone dry which is good because there appears to be no way to replace the felt seal wthout disassembling the gearbox!

I thought maybe I was getting some leakage around the drain plug so I tested it for tightness. It was tight! How tight was it? It took an 18" breaker bar with an adapter for the socket to loosen it. The parts breakouts I've seen show what looks like a soft disk seal and Moss technical referred to having them dry out and leak. When I got mine off, it was a copper ring type. The new one from Moss was too.

I reassembled everything and, before refilling the gearbox, I measured how much oil had drained out. I got about 34oz. or just over a quart. That's a lot more than what the manual says (1.25 I-pints which translates to 1.5 U.S. pints)

So overfilling could have expedited the leakage but... My dipstick did not and does not show ANY oil at all! The dipstick looks like the ones in pictures but who knows?

Does anyone (Tony, maybe?) have a clue why, even if there was over a quart in the box, it still didn't show on the dipstick?

Baffled but still confused,

Adam

 

[tony barnhill]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:]Originally Posted By: vping
...unless there is a huge MG out there that will fit 5 with luggage, camping gear and the occaisional pooch or 2.[/QUOTE]
1960 MkIII Farina Magnette will!

Oh, I'm just reading along learning something about the old cars!

 

[Steve_S]

A leak from the speedo connection on the gearbox is normal. Try fitting a thin o-ring or rubber washer inside the nut.

The threads on the drain plug may be loose from age. Put a new copper washer on the drain plug and snug it down well. If that doesn't cure it, try a small amount of teflon tape on the male threads.

Fill the gearbox until it reads correctly on the dipstick and make sure the dipstick itself is fully seated. Also make sure the car is on level ground and the gearbox is sitting properly in the car, i.e. not leaning or sagging.

If you think you have the wrong dipstick, measure it and we'll figure out the correction factor.

 

[Adam58]

Thanks, Steve!

The dipstick is 2 5/8" from the tip to the base where it seats. It has no markings but has clear crease at 5/8" from the tip.

With what s/b the correct amount of oil (see above), it does not show anything at all. (The car is in the garage so it &%$#@ well better be level!)

 

[Steve_S]

I'll climb up to the YB and check the dipstick some time between now and the weekend.

 

[vping]

OK so where can I get an affordable one of those pics or a
1960 MkIII Farina Magnette? What is that pic anyway?

 

[tony barnhill]

Octagon Auto in Felton, PA has one for sale...https://www.octagonauto.com/Carsforsale.htm