Fluid On U-Joint

[BAMFGOAT]

Hey there,

I have had a very slow drip that has been falling off my u-joint for a while now. I have a 280 tranny in there, and I heard that the output shaft seal could be the cause of this. So I replaced the seal yesterday and saw this morning that there was still fluid coming from the same area. I heard that the slip yoke could possible be the culprit in this case, but I wanted to get some opinions before I venture into that realm. Anybody have any insight?

Also if anyone would like a quick write on the seal replacement, please let me know.

Thanks!

[bertvorgon]

Many, Many years ago, I had the same issue. We at that time got a new bushing for the tail shaft and honed it for a really nice fit. If there is excessive sideways play, that will let the seal not be really round as the shaft can sag a bit. It also make sure that the drive shaft slip yoke is running nice and true, which really helps drive shaft vibration issue.

[BAMFGOAT]

Thanks for the input, bertvorgan. I also read a little bit about the bushing being a possible culprit. Do you happen to remember how difficult it was to remove the bushing? I've heard that it requires a special tool since it sits on the yoke pretty snug.

[bertvorgon]

I wish I could say I remember, that was back in 1983-84. What I think I remember is that Andy either made a machined drift, to get it out, and then the same to press the new one back in. I do not remember any problem at any rate, then he honed the bushing.

[BAMFGOAT]

Gotcha. Sounds like I might have some difficulty (impossibility) doing this out of my garage with the tools at my disposal. I'll try to exhaust some other options before taking her in. I appreciate the info!

[datzenmike]

The F4W71B four speed used in the 620/240/260 280z had a bushing in the tail #32132-78000. None of the 5 speeds (FS5W71B) or the F4W71B in the 280zx (used only one year '79)uses them. I guess Nissan figured they didn't wear out enough so the case is bored to fit and support the end of the mainshaft.

You could purchase one and have the case bored to accept it (if a 5 speed, you didn't say), but 4 or 5 speed, likely would need to be reamed to size. Easier to just find another rear case.

[bertvorgon]

Hey Mike, as you are the guru of transmissions...and...you triggered actually long forgotten memories of how many 5 speeds I tried.

Question, What transmission then would I have changed that bushing in...would it have been the one with the tall 5th gear? I know we changed one of them and, not likely then my current 5 speed from Nissan Comp, when they blew out all the close/mid ratio stuff.

I know I started with the 2000 roadster gear box, but once I started to turn the boost up, that long main shaft did not handle my torque well and bent itself quite nicely.

Then, as Andy used to buy ICBC wrecks, we pulled all sorts of stuff out. I hated the tall 5th gear one, .7 if I remember correctly, I just had a tough time pulling that gear at KNOX, even with 20" tall race tires on.

I do know one of them got changed and as my car had such high top speed capability, which got used a lot, we did everything to minimize power train vibration issues.

[datzenmike]

The '80 zx was 0.773 and the '81-'83 were 0.745 (25.5%) over drive. I can't find that bushing on any of the 71B 5 speeds, that's '77 on up. The 71B four speeds had them till about 79 then no longer listed. The 'late '77-'80 810 4 speed doesn't have it.

The Roadster 4 speed box F4W71A had the same bushing part number. 32132-78000

The Roadster 5 speed I think also uses a bushing. poooobably the same one.

Any chance the case wore out and Andy fitted a bushing to it???

[bertvorgon]

Morning Mike,

Who knows.....40 years ago. I do know I ended up basically destroying the roadster box, so it was not that one. I just can't remember if it was at the transition from my 72' to my 73', which I built in 1978, and then the re-do after my crash at Westwood in 83'.

I will see if I can find my first log book, as I started those in 1978, see if I made a note there.

EDIT: I put the tail shaft bushing in in March of 1985. My log states it was from a 1981 280ZX, ( Andy bought the wreck from ICBC) which is where I got my struts, Brake master, from also.
The Nissan Comp box came later, which is still in my car to this day. I got my posi diff from Electromotive in 1988.

Looks like I got my Comp box in 1991, I do remember it only cost 700.00CDN then when Nissan blew those out..I should have bought more!!!

I just did a trip through time..again...sorry for the thread jack.

[datzenmike]

Can't find the bushing listed in any 71B 5 speed after about '79. Would Andy remember if the casting was worn out and he bored it out to accept a bushing, maybe? Other than that I don't know.

[okayfine]

What kind/quality seal did you use? Lots of seals out there, not all are created equal. Could also be an install issue, if it's cocked or got nicked. Grease in the ID channel?

A driveline shop should be able to tell you if your stub is worn; lotsa spare stubs out there.

[BAMFGOAT]

Haha, glad to see that this thread sparked some (hopefully good) memories for you, bertvorgen.

Okayfine, I used a Timken replacement seal. It sat nice and snug so I'm hoping there's another explanation for this leak. Here's a a photo of the issue:


The yoke itself is pretty dry, so is this possible that this is liquefied grease? Am I taking crazy pills?

[datzenmike]

I see the problem. Trans fluid is slipping out the inside of the spline. You can see the spline just ahead of the U joint. The area should be sealed off.

You could just replace the spline end on the driveshaft or de-grease it and stop up the end with some urethane sealer.

Any idea what the spline is off of??? Kieth... doesn't the 71A have a flange on the end of the transmission? Or doesn't your 5 speed have this???




The 521 truck has a bolt on spline. The drive shaft bolts to it.


So if unbolted to use on a dogleg or any other transmission there is no nut to seal the hole. This is not what you have but for the 521 a 40mm engine core plug will seal it up...

[bertvorgon]

The 5 spd IN my car has the slip joint and the universal is a cast piece and hence sealed off, so no oil can go down the splines.

The spare close ratio I have has the flange on it. Andy and I do not know if it came from Nissan like this, or, if it was modified.

[Chickenman]

Haha, glad to see that this thread sparked some (hopefully good) memories for you, bertvorgen.

Okayfine, I used a Timken replacement seal. It sat nice and snug so I'm hoping there's another explanation for this leak. Here's a a photo of the issue:


The yoke itself is pretty dry, so is this possible that this is liquefied grease? Am I taking crazy pills?

If I recall correctly, some early units had a metal cap over the end of the yoke so that Oil couldn't leak out. Like a frost plug, but with no lip. They were just a press fit. I think yours has gone AWOL. Maybe someone can double check that if they have an early shaft.

At least my 1200's were that way. I had a mysterious leak there as well, and found that some one had drilled a " Vent " hole in the middle of the Cap for some strange reason. Welded the hole closed and no more leaky.