Dripping Oil at Rear of Transmission and Driveshaft

[Jonnymkiii]

I'm trying to find the source of an oil leak and was wondering if anyone else has seen these symptoms. When I drive the car and get back home, it drips oil directly under the rear of the transmission and cross- member support bar. I put paper under to catch it and it's motor oil and not transmission fluid. I checked inside the transmission inspection plate and it's dry in there; no oil, so not the rear main. I checked the sides and front of the engine as well as underneath and I can't see a leak on those 3 sides of the block. I felt behind the rear of the valve covers and I didn't feel any oil.

It would seemly have to source from the upper rear of the engine to traverse down the transmission and drip down at the rear, but I've not been able to locate it. I am thinking I'll need to get a scope with a camera to peak at the rear of the block.

Has anyone seen these symptoms and if so, what did the leak end up being?

 

[Guyana00]

I'm thinking valve covers at the corners. As described I would say tranny fluid if you weren't sure it isn't already.

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[Jonnymkiii]

Thanks for the input! I thought it might have been the valve covers as well, but changed them over the weekend and it's still dripping. When the engine cooled down I felt behind there and didn't feel anything that felt slick or oily, but that's only a surface test. I am going to put in some UV dye and get her up on a lift on Wednesday to see if I can see where it's coming from.. I might also need to get a color video scope to see what's going on in the block since there is so little space back there to look.

Some of the usual suspects that I can think of are..
- Valve covers: Possible, but don't feel any oil with my hands. Will need to better inspect with scope or mirror
- Rear main: No oil in transmission, so I am pretty sure that's not it
- There is a plug for the oil gallery on the rear of the block, but that might be covered by the bellhousing and if it is, I would assume it it were leaking, I'd see oil inside the transmission?

What else could possibly be leaking that is traversing the transmission all the way to where the driveshaft meets the transmission? Hopefully the dye will help track the bread crumbs, so to speak.

 

[plaaya69]

I remember from awhile back a few people had issues with the head gasket itself leaking from where the oil drains from the rear of the cylinder head to the block. I would check that and also I took a picture from my upcoming build and circled the oil plug on the rear of the block that could also be a spot to leak from for a better view. Another thing on that rear main seal, it also has a paper gasket that goes behind the rear main seal housing and I would add that to a possible spot too. Definitively some dye will help.

 

[Jonnymkiii]

That plug on the back of the block is what I hope it is.. pray for me that it's not the head gasket leaking!

 

[Guyana00]

Post the results very curious

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[Jonnymkiii]

As it turns out, I was wrong about it not being transmission oil. I have only changed the transmission fluid once myself, so I wasn't that familiar with the color of the lube, but I mistakenly assumed it was red for mantuals as well. Anyhoo, it looked and felt like new oil, but I made the wrong assumption that it was.

So it is coming from the transmission. I pulled the driveshaft and can I get someone to confirm that is a seal (Picture attached)? Its not a Toyota seal, but I just want to make sure that is indeed an oil seal for the transmission. I'm not certain this is where the leak is coming from.

Looking at where the speedometer cable connects to the transmission, when I tighten the transmission cable by hand, I can see a little bit of oil around the piece that is inside the transmission. Has anyone seen the transmission leak here before? I tried to find the part that is inside the transmission and connects to the speedometer cable HERE, but I don't see it there. If this is the source of the leak, does anyone know the part number I need to use to get a replacement? Thanks in advance for any input.

 

[plaaya69]

I just put that same rear transmission seal in my r154 that is going in my Supra. It is a Timken seal but I personally probably should have went with the OEM one (has a full rubber coated exterior like the engine seals). If you remove the bolt holding the speedometer cable housing to the transmission and slide the piece out of the transmission, you will see a rubber o ring which could be a possibility for a leak.

 

[Jonnymkiii]

Thanks for the i input; I'll call Toyota tomorrow to see about getting a new o-ring.

For the rear oil seal, if I wanted to pull that one out and put in a Toyota seal, should it pop out with a seal puller or some form of a pry bar? Since I'm in there and I have a OEM seal, I'd like to replace it.

 

[plaaya69]

No problem.

I was lucky to have the transmission out of the car and with standing it up, I used a flat head screwdriver at different angles to remove the OEM seal but if I were you I would invest in a seal puller since your transmission is still in the vehicle.

 

[Jonnymkiii]

I ordered an oil ring, so hopefully that's it. I made sure oil wasn't seeping from inside the gear; I can see oil around the perimeter of the gear where it goes inside the transmission, which I don't think is normal. If the leak isn't the rear oil seal or the speedometer gear box, could it be leaking from the top of the transmission where the portion that holds the shifter connects to the top of the transmission? As you can probably tell, I don't have much experience with transmissions, haha. In 25 years of owning this car, this is the first time the transmission has given me any issues and I just had it rebuilt.

 

[Jonnymkiii]

Well after replacing the real oil seal on the transmission and the o-ring on the speedo gear box, it is still leaking into a small pancake size puddle. I haven't jacked the car back up, but where ever the source is, it's dripping onto the transmission support beam and dripping to the ground from there. Back to the 'ol drawing board

:kickinthenuts:

 

[supraguy@aol]

So? Any update?

 

[Raggan]

it's probably the shifter retaining plate gasket mine drips down the back of the transmission.

 

[Jonnymkiii]

Sorry for the delay; the car was fixed on Monday and this week has been hectic, so I haven't been online as much. Raggan hit the nail on the head! I have a short throw shifter and it was indeed leaking from the shifter adapter plate that bolts to the transmission. I wound up taking it to a transmission shop and they found it and sealed it up. So far so good, no leaks at all. This was a PITA, but I'm relieved that it's fixed.

 

[Raggan]

nice