I dont know if any of you have followed my swap threads but here is a quick recap.

Swap went well but the transmission blew out the front seal after 400 - 500 miles. Losing about 5 qts every 100 miles. This was because I was given some bad advice and was told to bolt the torque converter to the engine then mate to the trans. I spent MONTHS trying to get the two together and ended up scratching the input shaft seal causing the oil leak 500 miles later.
Fixed it and its been perfect for 4500 miles.

So today, I step outside and notice a pool of oil under the 4Runner. I initially thought it was from the oil filter as its had been seeping a bit. Yesterday we had just done a 140 mile road trip and I figured the filter had loosened.

Nope, the oil is trans fluid and its slowly dripping out of the bell housing. This sucks as I now have to somehow drive the 140 miles back home.

Anyway, any ideas as to what the hell is happening? Why is the input seal wearing out? The only thing I can think of is that when the torque converter is in lock up there is some drive train vibration. Could it be out of round? I am looking for a torque converter from a 3.4, so if anyone has a known good one and is in great condition, please please let me know.
Should I replace the flywheel/flexplate too? Could the crank shaft be bent? There is no leak from the rear main. What about a bent input shaft?

 

Wow, 5 qts every 100 miles is a major leak.

Well, the obvious is your leaking from the input seal, oil pump seal, or both. You should replace BOTH while you have the tranny dropped.

The torque converter hub is the only component that actually makes contact with the seal, so that would be the main culprit in damaging the seal. Improper removal of the torque converter when seperating the tranny and engine could conceivably damage the hub, but I doubt the entire length of the hub would be out of round, and you would see an immediate leak if this was the case. Any scratches on the hub would be more likely to tear the seal. Did you put grease on the lip of the seal during installation? You need to.

The tc hub could be worn.

Another possibility is the leak is coming from the tc itself. Never seen one leak, but it is possible.

Until you actually remove the tranny and inspect, everything is going to be a guess.

 

Ok, weird day. I went under the car again after starting this thread and looked at the color of the fluid. I have about 1000 miles on the engine oil and the trans fluid is a mix of old and 3 qts of new. Basically it is VERY hard to tell which is which with a smear and a patch on the ground. You need some in a cup to tell. Anyway I looked around and noticed the oil filter was dripping and I managed to tighten it up one full turn. Could engine oil run along the block and collect on the bell housing in enough quantities to look like a trans leak?? Possibly.

So, still not convinced it was engine oil I looked at the oil and trans fluid levels and they were inconclusive. Engine looked low but ok, trans slightly low. So at the start of our 140 mile drive home this afternoon I put a qt in the engine and a qt in the trans.

Got home tonight and the whole under side of the truck is covered in trans fluid. Dripping all the way back to the rear diff. Spray on the rear window - everywhere.

I shat bricks. Then noticed fluid was on the top of the trans. Hmmm venting? Yep. From the vent back fluid is all over the place. Checked the level and its higher than it was when I checked it this morning but still only at the high level for cold. Obviously after 140 miles, the trans is hot, so its reading low and full or its venting too much. So, there is fluid all over the place, except at the very bottom of the bell housing where it dripped when the seal was destroyed last time. So I have my fingers crossed tightly that it was oil from the engine oil filter afterall, collecting at the bell housing.

I'll update after I've power washed everything off and driven it for a few more days.

 

Possible. If you have that bad of a leak at the filter you would also have oil leaking directly below along the block, onto the pan and also onto the front crossmember. 3/4 - 1 full turn is what it takes to tighten the filter, so basically it was just barely squeezing the oil filter gasket. Good thing you caught this.


If ATF is coming out of the vent then you are overfilled. To check the ATF level the transmission must be at operating temp and you check the gauge (dipstick) with the vehicle idling in park. Don't keep adding fluids unless you can verify what the levels actually are.

 

Yes side and underneath the oil pan was wet. There was also oil on the cross member. Most of the oil though ran down the lip at the block and pan join, right around to the back of the engine. Wind probably blew the drips off the pan and onto the bell housing. It then drips off that and onto the front diff, runs forwards and drips off at the low point. And this is exactly what happens when the front seal lets go, minus a damp pan at the front of the engine. Pan still gets sprayed about half way along its length.

I've been testing it in drive idling. I've noticed though, that it doesnt seem to matter if its hot or cool, level doesnt vary.

 

Automatic Transmission Fluid Check:

1. Get a clean shop rag and eye protection.
2. Make sure vehicle is the "Park" or "Neutral" Postion.
3. Start engine.
4. Let Engine warm-up for about 5-10 mins or untill it reaches operation temp.
5. Open Hood.
6. Locate Automatic trans Dip-stick.(Usually Read in color)
7. Pull Dip-stick out once and wipe off with your shop rag.
8. Replace Dip-stick
9. Check fluid level again, you should now be getting the proper reading.
10. Add or drain fluid ass needed.
__________________________________________________ ________________
Automatic trans fluid is usually "red" in color for easy identification.

NOTE: Overfilling a transmission with fluid can result in pre-mature seal failure. Seek proper fluid level before operating vehicle.

 

I checked the level after a 20 mile drive and its now right at the high notch for hot.
There appear to be no more drips or just one or two that have stayed up on the tranny. Nothing has dripped on the ground at all.

So I decided I'd take it through a touchless car wash to try and remove some fluid off the under side.

BAD IDEA.

I either have water in electrical connectors, destroyed the maf or water has got into the fuel tank. IT ran great, nothing changed on the drive from the car wash to the store. An hour later and it ran like crap. No power, hard to climb up the revs, a couple of pops and bangs out the exhaust. Every so often it would spring into life and run perfectly. Did this for about 2 miles then cleared up and ran great for the 15 miles home.
I just took it out after a 20 minute stop and its missing a bit and down on power slightly.

What the hell have I gone and done this time? 4500 miles and not so much as an errant squeak. Now all of this in 5 days! GRRRRRRR.

Ps can a bad maf make you run rich?

 

Drips seem to be getting less and less but I still am on the fence as to what it is. I hope its engine oil still coming off the block from the loose filter. It makes sense as it was bone dry under there until I did the oil change AND the drips have slowed since I tightened the filter.

And it still runs crap today. Drivable but lumpy with not much power until it gets up high in the rev range where it suddenly and violently makes power and takes off. So violently that if it were a wet road, it would light em up.

 

Just took it for a hard and fast blast on a 5 mile run. No drips and no hesitation.

 

Glad to hear it's running better. I got my ecu wet once and it acted just like you were describing. I pulled it and set it on a furnace vent for a day, has been fine since then.

 

It could have been the ecu. I noticed that the bolt that mounts it to the body goes all the way through the wheel well, leaving a nice hole for water to spray right onto the top of your ecu.

 

When my windshield started leaking it poured water onto the ECU... it did the same thing for me as well..

 

This was with a 3.4 ecu?