May I have advice on how to handle my leaky rebuilt T18?

Clutch, transmission, rear axle

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robroy
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May I have advice on how to handle my leaky rebuilt T18?

Post by robroy »

Good morning!

Now that I've driven #50 ~75 miles or more, I've begun noticing a number of leaks. I think I'm doing OK with resolving all of them, except for the T18. I'm not sure what to do about it!

The T18 leaks. It sweats gear oil. After taking the truck for a 5-10 mile drive, a ~1" wide gear oil spot forms under the truck. It's also getting all over the crossmembers.

I should probably use solvent to make it immaculate, then drive it again and try to see exactly where the leaks are coming from. Yet the leaks appear to be coming basically from every possible place, other than the output/yoke seal.

This photo shows the areas I'm looking at. There's always a fat drop forming at area A. The crossmember at area B has lots of oil on it, and the crack between the transmission and bell housing is wet (area C). Area C's the one that concerns me the most, naturally.

Image

Another photo:

Image

Today's Questions:
  1. Is it normal for a T18's seals to sweat gear oil like this? I have to admit that I've yet to see a dry T18, but I've never seen a freshly rebuilt one either.
  2. Does the gear oil in the crack between the T18 and bell housing mean that there's an input shaft leak?
  3. Do y'all think that by running it as-is, I'm getting gear oil on my clutch?
  4. Would any of the T18 seals dry out in storage? The transmission sat empty for over a year before I installed it and loaded it with oil.
  5. Could this situation be a metaphysical sign that it's time to swap my T18 with a 4:1 T19a?
  6. What should I do?
Thanks so much for all the fabulous advice y'all have dished out over the years!!!
Robroy
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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by forrestbump »

Robroy, it's been many years since I've owned a truck with a granny truck trans, but here goes my recollection (from my faulty, at best, memory)...

I'd start by checking that all inspection covers are tighten to the correct torque values. It IS possible that some of your trans gaskets dried out from sitting. You could remove the covers, apply a light coating of "Good Stuff" on them but, of course, that will require that you drain the trans first.

Does your trans have a new breather vent (pop it valve)? I installed a nipple with neoprene hose and one way breather valve mounted as high as possible on mine so that gear oil wouldn't escape and water/debris couldn't enter trans. Your valve MAY be defective? It's also possible that the trans was slightly overfilled with gear oil and it's creeping out the breather... just a thought.

This is all conjecture and the trans may simply seal itself after it's gone through some heating and cooling cycles. As far as getting gear oil on your clutch, anything is possible, but I don't see anything in your photos that I would call "Excessive Leaks"

Hope that some of this helps! Godspeed in finding a solution!!
1970, 2WD, F-250, C/S, Dual Tanks, 390 FE (of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Sky View Blue, Ranger XLT

1970, 2WD, F-250, C/S, A/C, Dual Tanks, 390 FE (again, of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Wimbledon White & Sky View Blue, Ranger (almost twin brothers!)

"One of the greatest discoveries a man makes, one of his great surprises, is to find he can do what he was afraid he couldn't do" - Henry Ford

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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by robroy »

Good morning Larry, thanks so much for your quality reply!
forrestbump wrote:Robroy, it's been many years since I've owned a truck with a granny truck trans, but here goes my recollection (from my faulty, at best, memory)...

I'd start by checking that all inspection covers are tighten to the correct torque values.
This is a great suggestion--thank you. I think I tried to re-torque the PTO cover bolts and they were OK, but I don't remember re-torquing the top cover bolts. This seems like a great first thing to try.
forrestbump wrote:It IS possible that some of your trans gaskets dried out from sitting.
I was afraid of that! I think one of the top morals of my #50 story is that a guy should buy major rebuilt components like transmissions and engines only when he's ready to put them in to service, and not try to get smart and efficient by ordering them in advance!
forrestbump wrote:You could remove the covers, apply a light coating of "Good Stuff" on them but, of course, that will require that you drain the trans first.
That's a good idea, and I guess that wouldn't be too hard to do. I'm supposed to replace the gear oil after the first 500 miles anyways so there's an automatic chance for that.
forrestbump wrote:Does your trans have a new breather vent (pop it valve)?
No--I actually didn't know those were available! It has the same old one, and I don't remember making any special point out of verifying that it still worked. I should definitely look at that again!
forrestbump wrote:I installed a nipple with neoprene hose and one way breather valve mounted as high as possible on mine so that gear oil wouldn't escape and water/debris couldn't enter trans.
Fascinating! I had no idea that this was an option. May I know how you found an appropriate one-way breather valve? I'd have no idea where to buy something like that.
forrestbump wrote:Your valve MAY be defective?
Very good thought!!!
forrestbump wrote:It's also possible that the trans was slightly overfilled with gear oil and it's creeping out the breather... just a thought.
Well I filled it up to the top, just so it started to come out the shifter cane opening. :D Just kidding! I remember squirting the oil in to the upper filling hole (not the shifter cane opening on top) until it just started to seep out. There's still a chance that it has too much fluid in it though, I suppose. And at its current leak rate that should be cured in a few more drives. :)
forrestbump wrote:This is all conjecture and the trans may simply seal itself after it's gone through some heating and cooling cycles.
That would be nice! Maybe it wouldn't hurt to drive it at least a hundred more miles before doing any big repairs.
forrestbump wrote:As far as getting gear oil on your clutch, anything is possible, but I don't see anything in your photos that I would call "Excessive Leaks"
Oh, that's great to hear. Maybe if you saw the amount of fluid pooled up around the crossmembers you'd change your mind, but then again, I've yet to see a dry T18 case so it's possible that this leakage comes with the territory.
forrestbump wrote:Hope that some of this helps! Godspeed in finding a solution!!
It does help Larry--thanks very much!!! I'll investigate those things and report back.

Thanks again for your excellent reply Larry,
Robroy
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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by forrestbump »

Robroy, here's something I found online just a few minutes ago and admit I did NOT read all that was written.

http://www.getahelmet.com/jeeps/tech/waterproof/

It's NOT a source for the breather valves, but it does explain what I referred to in my last post. I DO have some of these breather valves left over from an old dead project and I'll probably never use them so they're yours for the asking. They are of nylon construction and they're off of a Chebby 4WD, 205 transfer case (do NOT tell anybody where they came from or I'll be shot).

Again, Hope this helps!
1970, 2WD, F-250, C/S, Dual Tanks, 390 FE (of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Sky View Blue, Ranger XLT

1970, 2WD, F-250, C/S, A/C, Dual Tanks, 390 FE (again, of course), C6, Power Steering, Power Disc Brakes, Dana 60 3.73, Wimbledon White & Sky View Blue, Ranger (almost twin brothers!)

"One of the greatest discoveries a man makes, one of his great surprises, is to find he can do what he was afraid he couldn't do" - Henry Ford

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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by robroy »

Good evening Larry, thanks for replying!
forrestbump wrote:Robroy, here's something I found online just a few minutes ago and admit I did NOT read all that was written.

http://www.getahelmet.com/jeeps/tech/waterproof/
Thanks for this! I'll read through it.
forrestbump wrote:It's NOT a source for the breather valves, but it does explain what I referred to in my last post. I DO have some of these breather valves left over from an old dead project and I'll probably never use them so they're yours for the asking. They are of nylon construction and they're off of a Chebby 4WD, 205 transfer case (do NOT tell anybody where they came from or I'll be shot).
Well thank you very much for this kind and generous offer Larry!!! I think I may be OK with the existing valve though, but I'll remember your offer in case I want to update the valve.
forrestbump wrote:Again, Hope this helps!
Indeed Larry!!! Thank you!

Today's Update:

Since I was working in the area, I checked the torque on the PTO cover bolts, and set them to around 20 ft/lbs. Maybe that's a little too tight but I thought I'd try it.

I had the transmission tunnel cover off so I could see the top plate clearly, and it was actually pretty dry around the top plate. But I did check out the breather and, just as Larry mentioned, the POR-15 I'd put on the top plate HAD interfered with it!

Image

I tapped it lightly with a hammer to break it free, and then it was possible to freely wiggle it around in there, just like normal. So I'm hoping that was a significant contributor to the leakiness!!!

Then I checked the torque on the rear housing bolts, as shown here:

Image

The Ford manual said about 107 ft/lbs for these bolts, and several of them were around 50 ft/lbs! So I fixed that.

I'll have all the gear oil out in another one or two hundred miles, and I'll try to re-seal the PTO cover then. Hopefully I'll be OK at that point!

Larry, thank you again for your generous advice!
Robroy
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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by 70_F100 »

Robroy, I think you may have mis-read your manual. :hmm:

Those bolts have either a 5/8" head (7/16-14 bolt) or 3/4" head (1/2-13 bolt). I've got a bad case of CRS right now, and can't remember which (but I'm pretty sure it's the 1/2-13)!!! :doh: :doh:

For the 7/16-14 bolt, the manual calls for 30-38 ft/lbs, and for the 1/2-13 bolts, it's 50-62 ft/lbs.

107 ft/lbs would be for a 5/8-11 bolt (15/16" head).
Wise men talk because they have something to say; fools talk because they have to say something.--Plato
Why is it that there's seldom time to fix it right the first time, but there's always time to fix it right the second time???

That's not an oil leak :nono: That's SWEAT from all that HORSEPOWER!! :thup:
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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by robroy »

Good evening 70_F100!

You are absolutely correct!!! I got too hasty with that. I went and re-checked in the manual and discovered that I was indeed reading the wrong number.

Now, the question is whether I'll pull the transmission cover off again to fix it! I probably will, since it will bug me knowing that the bolts aren't happy like they ought to be.

On the other hand, is it possible that these bolts aren't highly torque-sensitive, and that most mechanics tighten them down with an impact wrench anyways?

Thanks very much for letting me know 70_F100!
Robroy
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Re: May I have advice on how to handle my leaky rebuilt T18?

Post by robroy »

Good evening!

I finally took the cover back off and re-set the torque on those bolts! Now I can rest easier knowing that they're not stressed out.

Here's how the area looked:

Image

The transmission still leaks pretty quite a bit, yet I'm less concerned than before, since I'm still thinking of ultimately replacing it with a 4:1 T19a. I'll still at least try to re-seal the PTO port cover when I change the gear oil (pretty soon, since it's still running the gear oil I first put in after the rebuild).

Thanks again for the excellent advice!
Robroy
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