1st Gen Trans Rear Output Seal Install Thoughts

I've got a 96 tacoma with the 2.7l and the w59 4wd trans.

Over the course of the last few months, it has developed a leak out of the rear output seal. I've replaced it with dealer seals and autozone seals, it doesn't seem to matter what i do, it's still slinging oil everywhere under the trans.

I drop my driveshaft, take the pinion nut off the back of the trans, count the turns, pull out the output and slide the seal on and then put the output back in and bolt it all up.

Am i missing something? Do i need to check my output for play or am i installing the seal incorrectly or something? Truck has 210k on the odometer but carfax says it could potentially be in the 300k's

On a side note, I've gotten pretty quick at doing this job lol
Also searched, but only seemed to find stuff relating to the 2nd gens.

 

I am confused do you have a 4x4 or a 2wd with a W59 cobbled in

If so I have never seen a 2wd so disregard

You in theory should be using a new nut !

You are at least staking the nut after you torque it to 110 foot pounds

Is the shaft worn on the transfer case enough so the new seal leaks might need to adjust just where the seal rides

 

Are you applying grease on the lip of the new seal? Inspect the output flange for a groove worn into the sealing surface.

 

Mine is 4wd. All stock drivetrain.

Ill get a new nut next go around

How do i adjust where the seal rides? To check if the shaft is worn jus see the side to side and up and down play?

 

I haven't been putting grease but i will try that. I havent recognized a groove although i havent been looking hard for one

 

Post pics. I have had the output shaft seal leak after a brand new rebuild, then I got an OEM seal and all was good.

Where is the leak? the output shaft seal between the transfer case and trans or is it at the output flange of the transfer case?

 

You can most often see if the shaft is scored with your eyes .

feel a worn spot with a finger nail.

after doing this to long some of these things are second nature

like coating the seal surface with oil when installing

 

Ill post some pics this afternoon after work. And i think the output flange of the transfer case.

 

Ima pull it out and check it out good in the next day or two. Part of my problem may have been ive done it in a hurry.

And coating the seal surface with oil is something i should have known to do.. brain fart

 

Ok, so have you checked to make sure the thing isn't overfilled?

I know it sounds elementary, but I was a mechanic for spec miata team and I had this similar case happen: I was asked by my owner to go look at another team's miata because they didn't have a tech and they were friends. They said that the manual trans output seal is leaking all over. I got a new seal, lifted the car up and pulled the driveshaft out, and a bunch of gear oil flowed out.....I guess whoever filled it, decided to fill it from the top of the shifter and it was WAY overfilled. I popped the fill plug on the trans and let the gear oil drain until it stopped coming out (proper level) and replaced the seal. No more leak, and transmission felt smooth as silk. Just an idea.

The transfer case has a fill and drain. Pop the FILL plug open and make sure it drains until it stops coming out of there.

If this is not the case, then the only other way the seal would be leaking is if the flange shaft that slides in, has a burr on it and is cutting/damaging the seal or it is worn out not allowing the seal to make contact. You should see a shiny area on the shaft where the seal rides. make sure that is clean and take some green scotch-brite to remove any heavy deposits. When installing the seal, make sure the casing where the seal slides in is also clean and not damaged. Remove any burrs and finish up with scotch-brite. use some gear oil to lightly lubricate the outside of the seal and install it. When installing the flange shaft, take your finger and lubricate the inside of the seal with gear oil and lubricate the flange shaft that slides in. Make sure it is centered and slide it in and torque it to spec with any shims that the parts diagram calls for.

 

I know its not overfilled because the first time i replaced the seal i changed out the fluid. So i guess i need to pull out the flange and inspect it for starters

 

If you have a groove worn in the flange where the seals have been riding, finger nail inspect, get you a speedy sleeve and install it, done a bunch in the past.

 

You can actually see the fluid build up from the leak here.

 

If by chance your vent is plugged it will push out even with a good seal .

Something else I check and don`t think about

 

What he said. I had a 1rst gen that was doing the same thing. The vent was plugged causing presure to build up and was pushing gear oil through the rear seal. A good way to check for pressure is to remove the full plug immediately after driving it for a little while.

 

Pictures speak a 1000 words they say. I agree with above. Be sure the vent line is block free and clean everything with brake cleaner. See if the leak comes back. If it does, remove the flange and see if the leak is coming from the OUTSIDE (Part that gets pressed in to the case) or INSIDE of the seal (part where the flange rotates). This will narrow down what needs to be done next.

 

I take it the vent isnt the little breather line that attaches to the shifter.

It may be on the 5 speed shifter and not the 4wd one. I remember one had a vacuum line on the shifter base

 

The breather attaches from the transmission to the transfer case.