how do you change 904 front pump seal??

[john27pa]

May sound like a stupid question, but its not because I dont know how lol. Anyway, I have a late 70's 904 trans. I believe it has lock-up on it- smooth on end of shaft instead of splined. Came from a 78-79 360 Cordoba. Im looking at the front seal area and I am guessing that you have to take the front pump off to change this seal-am I right? Will I lose a ton of fluid everywhere? Any tips? I will be searching through the archives more-havent found what I am looking for yet, but please help here if you know how. Trans is laying on ground under car as we speak. Any other tips, tricks, or should do's while its out? Is there a pump seal that would need replaced for around the bolt holes for the pump also?? Or just undo and replace pump seal by shaft?

 

[fishy68]

No you do not have to take the pump out. All you need to do is use either a seal puller (available at Sears, Autozone, or most any other auto supply that sells tools) or even a large flat blade screwdriver will work. To use a screwdriver just insert the flat tip in between the seal and reaction shaft at an angle so that your catching the underside of the seal then push on the screwdriver and it should pop right out. Basically your using the screwdriver like a lever to pop it out. When you get it out make sure and clean area where it sets real good and apply some shellac type sealer (go easy on it, just a thin coat) or a thin coat of blue loctite. That'll help it seal better and not spin out of place. Plus it acts like a lubricant to help you drive it in easier. Speaking of driving it in, make sure it goes in straight. If it cocks on you it can warp the seal. grease the seal up where it contacts the converter snout so when you slide the converter in it doesn't scuff or cut it. The bolts do have little washer type seals on them and there is a big O-ring seal on the outer perimeter of the pump. Rarely have I ever seen the big O-ring leak. Saw a couple bolt seals leak but most of the time it's cause the bolts were loose. You might want to check to see if the bolts are tight and if not snug them up or if you have a inch lb. torque wrench torque them to 100 inch lbs. If the big O-ring seal is leaking you will have to remove the pump and that can be a little hairy cause the clutch drums can fall out of place then you gotta get things all lined back up to get the pump back in, but I have a trick. Before you take the pump out push the input shaft back in as far as you can by hand then loosen the locknut on the front band adjuster and tighten down the adjuster. That'll hold everything in place so nothing falls out when you take the pump out. When you put the pump back in make sure and remember to re-adjust the front band to spec or it'll trash the trans.