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truck kind of broke down (Transmission leak). (New info, Post 11)

colbystephens

colbystephens

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Took it on a 6 mile drive to the local brewery and it made a rattling noise on the freeway. We pulled into the parking lot and it's spraying transmission fluid out of the driver's side, above the pan. Underside of trunk is covered in oil. Wondering if this has to do with fouling up a seal at the gear selector input when adjusting it for my 1" body lift. Having it goes home.

Thoughts?

EDIT: See post 11. I think that the word "spraying" is a significant overstatement. I think it's a small drip that looks like a massive leak because the wind at 65 MPH was blowing it all over the underside.
 
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I doubt it. I don't think that seal sees much pressure. I would suspect the cooling lines.
A pinhole in the pressure side could spray all the way across the truck.
 
Perhaps saying its spraying transmission fluid isn't correct. I was driving 65-70 when I sprung the leak, which means wind+tires+spinning drive shaft=covered u desire.
 
In that case, you got to go to basics.
Spray it down with some kind of soap and hose off all the oil. Let it dry, look for a leak.
No leak, crank it up and look again.
No leak, drive it to the end of the driveway and back and look again.

You got to find it when it first starts leaking so you can tell where its coming from. After its goes all over, you can't tell.

All that after filling it back up, of course.
 
Home now. Had a tow.

Do you suppose this is the seal needed for that gear selector input? I know that I still need to properly diagnose this, but I'm just trying to get a feel for cost of parts, assuming it is in fact related to the seal at the gear selector.

In chronological order of how I'm finding seals on the NAPA site...

A/Trans Seal, Extension Housing (Metal Clad)
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=ATP13639_0360917106

Same thing as above, but without flange:
A/Trans Seal, Extension Housing (Metal Clad)
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=ATP12727_0360917104

Or perhaps it's this one?
A/Trans Seal, Man Control Lever Shaft (Metal Clad)
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=ATP13887_0121657947

Well, now I'm thinking it's most likely this one...
A/Trans Seal, Shift Shaft
http://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=NOS4912_0075420595
 
Doubt that it's the gear selector seal (also you would need to drop the pan and remove the selector shaft in order to replace that seal). I would start by having Claire start the engine while you look underneath to see where fluid is spraying from.
 
I had her do that and didn't see any leak. :dunno: I rinsed the undercarriage off, and looked underneath and it doesn't appear to be the gear shift input seal.

I did notice a bit of fluid on the dust cover, which has me concerned. I'll have to pull it off and see if it's the front seal. :( If the bearing walked out and were riding against the torque converter, would you suppose that I'd hear it doing so? Because I was hearing a noise on the highway.

I'm supposed to drive the Rubicon a week from tomorrow. :( :( :(

To the best of my knowledge, this transmission was a stock replacement installed less than 30K ago.
 
Scott has worked on more r4 transmissions than I have ever even seen. So its always best to listen to him.
But, in looking for a diagram that would give a correct part number for that seal, I found dozens of references to a tool set that claims to let you change that seal without dropping the pan or losing fluid.

Here is a link to one, http://www.technicalvideos.com/tools/700_shift_shaft.phtml

And here is a cheaper version on E-bay.
http://www.ebay.com/itm/GM-Transmis..._Automotive_Tools&vxp=mtr&hash=item53fa3da253

Never used one myself, but there are several stories online about folks who changed that seal with one.

Either way, you need to make sure before springing for parts.
 
If its a turbo 350 or 400, you can get one of those tools and change out the shift shaft seal without dropping the pan....I've done it many times.
Or...
You can also remove the external linkage,,wash out the seal area really good with brake cleaner,, lube up the new seal and drive it in next to the original seal.
The hole is deep enough to hold two seals back to back....

I do this just for grins when ever I do a rebuild.
 
My only advice is right now is to treat them like 2 problems.

Find the leak you may find the rattle. But it could be 2 different problems. Don't make the assumption that they are one in the same.

I am not sure what it could be maybe the breather? It dumps on that side. Not a whole lot over there really.
 
I've been out looking at the truck, so here's some new information.

1. The rattle is NOT related to the transmission. The problem is that I'm an idiot. I put that 1" body lift on there, and didn't think about the lower fan shroud. The fan was bound up in the shroud and couldn't spin. The clicking was the fan clutch. :doah: I removed the bottom shroud for now, clicking is fixed.

2. I decided to pull the dust cover off of the transmission and peak up in there to see if I could spot the leak. Well, the cross-over pipe of my exhaust prevents me from taking the dust cover all the way out, but I was able to get it out of the way enough to get a good look inside. It is dry as a a Nevada Summer in there. So that's good news.

3. Upon further inspection, I'm leaning more and more towards thinking the leak is related to the gear selector input seal. I got up in there with a light and saw that everything above that point is dry. There's a bit of a film of dirt/grime/oil on the driver's side lip of the transmission housing, and that leads me to think that there's been an ongoing small leak there.

Also, based on the way that my exhaust routes around the transmission, the exhaust pipes come together in a Y about 8" behind the gear selector input shaft. From the stains on the exhaust at that spot, seems to indicate the greatest amount of transmission oil is landing there - which makes sense at speed + gravity.

I'm thinking that the gear selector seal got a bit torn up somehow when adjusting the linkage for my body lift. So, I think I'll start there. There's nowhere else on the case that seems to indicate a leak, so... :dunno:

I filled up the transmission and went out on my street and romped on it really good. There seemed to be a couple new drips under the gear selector.
 
You might as well go ahead and buy a new fan clutch. Even though they are fluid drive, every time I have stalled one for more than a few minutes, it either quits or starts leaking within a week or so.

I suspect that its the same thing each time. When it gets stalled out, pressure builds up in the clutch fluid, and it blows out past a seal.
Since the way I stall it is by running the fan under water, I would not notice the leak since the oil would wash away.

Look around the shaft and the front if it has the spring.
Any wetness is the beginning of the end.

Mine usually fails when I'm in the woods, and I can't get the truck up to any speed for the air flow to replace the fan.
Since my fan is on the end of a shaft, I got good at tying a cord around the fan and wrapping it around the shaft to get me home at low speeds.
 
Today Owenst7 and I put a new seal in that shift shaft location. Wasn't too terrible of an ordeal. When I drove it home there wasn't a drop on my exhaust, so I think I'm in good shape. Frankly, I haven't been able to replicate the problem, save for a couple drops of fluid. The old seal was definitely looser around the shift shaft, so I at least fixed something today.

But I do have a theory. :wink1:

Because my fan got stuck in my shroud, I'm wondering if the transmission fluid temperature spiked and caused it to come out that port because it was so hot and thin. I do have a secondary transmission cooler. If that's the case, doing a fluid change in the pan gives me some peace of mind that most of the fluid is now new good stuff, rather than charred overheated stuff.

Truck drives great, so I'm just going to keep an eye on it this week and drive it more than I normally would so I can feel confident about taking it on the Rubicon next Monday. I'll bring a couple quarts of ATF with me just in case.
 
Man, I am serious. Watch that fan clutch. It will get you out to the Rubicon and strand you.
Grab a bright light, and look for any stains. Every time I destroyed one, it was only bound up for a few minutes, and at relatively low RPMs.

You had this one locked for a long time at highway speeds. I'm surprised the oil you saw did not come out of it instead of the tranny.

BTW, did you pull the pan to change the seal?
 
I am getting a new fan clutch. :thumb: Thanks for that recommendation. Actually, I'm getting one of dhcomp's clutches. :) It's a low-gear version, so that should be a nice cooling upgrade for my rig.

Yes, I pulled the pan to change the seal. That all went real smoothly.
 
Deisel fan clutch is the one you want. I'm running one in my Jimmy and never had cooling issues. I would not buy anything else.
 
Well, the one I ended up getting is one for a rig with 3.73 gearing or numerically higher, so as far as I can tell it should lock up more and pull more air. AC DELCO 1540131. Hadn't thought about going the diesel route. If I ever end up needing another, I'll try that.
 
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