Need to drop the fuel tank.....

D Hook

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I've got a seal leaking at the tail of the transmission where it hooks to the drive shaft and it appears the fuel tank has to come down to change the seal. I wouldn't mind so much but it's leaking right onto the cat. converter and makes a pretty gawd-awfull smell, not to mention the loss of fluid.

What else should be done while I got the tank out, you know, those "while you're in there" type of jobs. Maybe new fuel pump?
 
D Hook said:
I've got a seal leaking at the tail of the transmission where it hooks to the drive shaft and it appears the fuel tank has to come down to change the seal. I wouldn't mind so much but it's leaking right onto the cat. converter and makes a pretty gawd-awfull smell, not to mention the loss of fluid.

What else should be done while I got the tank out, you know, those "while you're in there" type of jobs. Maybe new fuel pump?



THATS A GOOD IDEA..DO U HEAR A HUMMING SOUND WHILE DRIVING? THEN YEAH CHANGIN THE FUEL PUMP,OR GAS FILTERS IS A GOOD IDEA...
 
Well you do not have to drop the tank at all to change the rear seal on the trans.

But yes, if you feel like getting some stuff done while the car is up then a fuel pump is a good idea as these thing have a tendency to go. A Walbro 255 is overkill but a great pump. Make a slight sound like a small jet engine. The Walbro 190 is much quieter and still better than stock. Both are "direct fit" and under $110.00.

U-joints are not a huge problem on these cars but good idea to replace them. There are tow basic types, one is sealed and the other has a grease joint. The solid ones are stronger but non-servicable.

Maybe change the read differential fluid. In my opinion is the one thing most often forgot about yet needs to be changed every 100k or less.

Cant think of anything else right now.
 
LOL... ya, it SUCKS being the only Mark VIII guy way up here! But I can't wait for the Boscobel Beach Meet. I have NEVER been at a Mark VIII meet. I think the cruise will be fun. I have a few things I need to do yet to the car, but it should be ready, I have all winter :)

Oh ummm, I should add the reason you do not have to drop the tank is because all you need to do it remove the front u-joint, just take it half-way off - leave it still attached to the yoke OR shaft. Then you can move the shaft out of the way and take that wonderful trans fluid shower!!! Make sure to drain the TC and put in Mercon V fluid, not III!!!
 
unity said:
LOL... ya, it SUCKS being the only Mark VIII guy way up here! But I can't wait for the Boscobel Beach Meet. I have NEVER been at a Mark VIII meet. I think the cruise will be fun. I have a few things I need to do yet to the car, but it should be ready, I have all winter :)

Oh ummm, I should add the reason you do not have to drop the tank is because all you need to do it remove the front u-joint, just take it half-way off - leave it still attached to the yoke OR shaft. Then you can move the shaft out of the way and take that wonderful trans fluid shower!!! Make sure to drain the TC and put in Mercon V fluid, not III!!!

Just had the fluid flush and fill done at the dealer two weeks ago. That's where we found the leak on the rear seal. The tech said the exhaust and fuel tank have to be removed to get the drive shaft out to change the seal. You're saying on the '98 MY, the tank does NOT have to come out, right? We're talking the rear seal on the end of the tranny. (I haven't gotten my repair manuals in yet. Expecting them by next Friday.) I hope not to have to refill w/the Mercon V fluid again since that would be a waste.

I trust the tech at the dealer because they've done work on my cars in the past and have always treated me well but I don't think they get too many Mark VIII's in there these days so they may not be up to speed on the repairs. We were just looking around the bottom of the car when we noticed the leak and he glanced at the position and figured the tank would have to come out. I don't think he actually has looked it up in the repair manual. I'll check with them again and have him do a little more research. In the mean time, thanks for your input. If anyone else has any experience replacing the seal, I'd apprecicate hearing about it.
Thanks!
 
Ok... by the book he is right.

Book method is to unbolt the four differential to u-joint thingy at the back of the shaft. Well thats fine, but the shaft cant move back to pull the yoke out of the trans and get to the seal. So you have to drop the tank and exhaust to pull that shaft back and out of the way. WAY more work than needed.

My method involves at least ONE new u-joint. The joints run about $20 max - thats a lot cheaper than all that labor. All you do is remove the u-joint from the yoke and leave it on the end of the drive shaft. Well now the shaft can be pushed up and out of the way just enough to slide the yoke out and get to that rear seal. I have done this before!

Shop books are all about labor and NOT replacing parts that should not have to be replaced. You could re-use the u-joint, but I VERY much recommend replacing it.

edit:

Either way, the fluid is lost if you do this. When you pull that yoke you may loose most of it.
 
Not sure if this will work but if you jack the rear up higher than the front could you keep the fluid in the tranny? Just a thought. Granted it will leave for a tighter work area at the tranny but it may work to save some of the tranny fluid.

Still Mercon V is only about $3.50 to $4.00 per qt. Just bought a case of Valvoline.
 

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