[t.mcginley.jr]

Hi all,

66 Mustang coupe, 289/auto C4 trans

I've had the car up on jack stands in the garage for a few months now while I'm working on it, and I noticed small puddles under both the trans and the rear. I know these are separate issues, but figured I'd kill both one with thread.

The trans appears to be leaking out of where the speedometer gear is. Looks like it's leaking slowly out of there, onto the trans mount and then to the ground. The speedo cable is also wet, further evidence of where it's coming from. Is there some kind of seal or O-ring that goes in there?

For the rear, I believe it's leaking from the pinion nut, or maybe the pinion seal? It's basically dripped out from where the driveshaft bolts up to the rear, slowly but surely.

Thanks!

 

[Yadkin]

There is a small O ring where the speedo cable "plug" goes into the transmission.

 

[Urambo Tauro]

Your pinion leak can probably be taken care of with a new seal, but don't forget to compliment the new seal with seal-saver/Redi-Sleeve (if not replacing the yoke/flange altogether).

And take the opportunity to see if you can wiggle the pinion. It should only rotate in place. If it moves in/out or wobbles around, the bearings are worn.

 

[t.mcginley.jr]

Thanks for the help guys. I've definitely confirmed that the trans is leaking from the speedo gear sits, the O-ring looks original. I needed to change out my 16-tooth gear for an 18-tooth one anyway, so this was a perfect time to replace the o-ring.

As for the rear, how do you get the yoke out to replace the seal? I'm guessing you take off the pinion nut, but then does the yoke just slide out? I bought the differential a few years ago, the internals are all new but I couldn't say if the yoke was used or not. I've never used a Redi-Sleeve, but it just presses on the yoke and lets the seal work better right?

 

[Tony 64]

Remove the tailshaft, remove the nut holding the yoke, remove yoke and the seal is just there.
Some people say to count the revolutions when taking the nut off so you can't further crush the crush washer any more. Some say to tighten to torque.
I did this but had to tighten it a bit more as I had a bit too much backlash in the diff.

Most shops use a rattle gun to tighten these nuts.

 

[6stang02]

Imho i would not use any air gun to install the nut... i would only use proper tools to do so. A 1/2" breaker and an in•lb dial torque wrench and get your pinion right at the 15"lb, if original bearings are used. 30"lb if they are new. That is how myself and my heavy line friend positioned mine after it leaked a nice stream when i refilled the diff prior to replacing. My pinion was not torn up either so i did not use the sleave. Good luck

 

[t.mcginley.jr]

Thanks guys, so if I understand this right.... after I replace the seal and slip the yoke back on, I have to tighten the pinion nut to whatever torque until there's ~15 in-lbs of rotating resistance? The whole thing is still in the car, so to get an accurate preload reading do I have to slip the axles out?

 

[Ivy66GT]

I would not use any impact wrench on the pinion of any car I own.

The Ford spec for your rear axle pinion preload is 17-27 in-lbs for new bearings and 6-12 in-lbs for used. Technically you should remove the axles but without wheels on them they probably won't make a big difference in your readings. Make sure the brake shoes aren't dragging.

Ring gear backlash is adjusted internally. You should not try, nor expect, to change backlash using pinion preload.

 

[Yadkin]

Just so you know, an inch-pound torque wrench is not that easy to find, and they are expensive. I ordered mine online and as I recall it was about $130. None of my mechanic friends own one- they borrow mine.

 

[Urambo Tauro]

It doesn't have to be a dial-type torque wrench; you just can't use a clicker on it. A beam-type will work, and the GearWrench lb-in one can be found for <$50.

And yes, the Redi-Sleeve just presses right onto the yoke. It provides a fresh surface for the seal to ride against as the pinion rotates.

 

[Tony 64]

First let me clarify that I personally would not use an impact gun on my cars either, I was just noting that many shops use one if you were to take it there.

My 64 Comet and Falcon shop manuals reads, "Drive Pinion oil and Seal Replacement" Page 4-11.
Note 2. Mark the pinion shaft nut, the end of the end of the pinion shaft, and the pinion flange splines for re alignment.
Note 9. Install the pinion shaft nut. Tighten the nut until the marks are aligned, then turn 1/4 of a turn past the alignment marks.
(obviously there are other steps between these two describing how to change the seal)

Torque specs as written above.

 

[Ivy66GT]

This one should do the job. Scale marking are 2 in-lb, max 60 in-lbs. Its only 1/4" drive so you will need some socket adapters to use it on a pinion nut.


https://www.amazon.com/GearWrench-2...h/dp/B00004SQ3B/ref=sr_1_1?ie=UTF8&qid=1473288254&sr=8-1&keywords=KD+Tools+2955

 

[Gt350HR]

I agree that a novice should do this job with the utmost in caution. Too tight is just as bad as too loose. The problem with an impact ( air or electric) is knowing when to stop. A used ( pre crushed) crush sleeve has little resistance to the force of an impact as opposed to a new un crushed one. "If" you can remove the front pinion bearing and access the crush sleeve, remove it temporarily. Once removed , You can slip it over a deep socket that fits inside of it. Then use a ball peen hammer and strike the raised portion in the center in four equal spaced points. This will expand the crush sleeve ( a slight amount) and reduce the chance of over tightening the nut while trying to obtain the proper preload. You can then put the spacer and pinion bearing back in place followed by a new seal. With the crush sleeve expanded it will take more effort ( tightening the pinion nut) to obtain the proper preload. While this is a "flat rate" line mechanic trick , it is FAR better than a loose pinion nut ( low torque value to obtain proper preload). It is much faster than trying to use a new crush sleeve. They are very difficult to crush ( initially). The Ford axle plant used a special hydraulic press fixture to do it back in the day.
If this is too much for your comfort level and you simply want to re tighten the pinion nut, I recommend a SMALL amount of red locktite on the pinion nut to keep it from loosening at a later date. It only needs to stay tight , not become one piece by the use of too much locktite.
Randy

 

[t.mcginley.jr]

Thanks for all the replies everyone!

I picked up a new pinion oil seal (and trans tailshaft seal just for kicks), and my new crush sleeve should be here today. If they are that hard to crush initially I might end up re-using the old one. I just dropped the driveshaft last night and will be taking the yoke and oil seal out tonight.

Is there a reason you can't use a regular inch-pound torque wrench vs. a beam style? I have a Craftsman one that I used on everything and seems to work fine... albeit it only starts at 20 in-lbs. I check pre-load last night with it after I got the driveshaft off, it didn't stop clicking off until about 45 in-lbs. Given this is with the axles still in, but seems a little high. A mechanic installed this the last time it was done, probably with an impact gun (which I won't be using!).

Also about the pre-load specs, would you consider bearings that have been in there for ~1000 miles be old or new?

 

[Urambo Tauro]

A click-type torque wrench is only for tightening fasteners to spec. It is not for taking readings. It won't give you real-time feedback of how much torque is being applied. You won't know if you're almost at spec, and even if you do get a click, you won't know how far past spec you might be.

Tightening the pinion nut is a back-and-forth process of forcing the nut tighter with a breaker-bar, then removing the breaker-bar and gently checking rotational resistance with the torque wrench. There will be a SLIGHT drag on the bearings. But you need to make sure that that resistance is not too much, and not too little.

 

[t.mcginley.jr]

A click-type torque wrench is only for tightening fasteners to spec. It is not for taking readings. It won't give you real-time feedback of how much torque is being applied. You won't know if you're almost at spec, and even if you do get a click, you won't know how far past spec you might be.

Tightening the pinion nut is a back-and-forth process of forcing the nut tighter with a breaker-bar, then removing the breaker-bar and gently checking rotational resistance with the torque wrench. There will be a SLIGHT drag on the bearings. But you need to make sure that that resistance is not too much, and not too little.

Gotcha, I'll make sure to buy a beam style inch-lb one.

So last night I was able to get the pinion nut off, slipped the yoke off and popped the seal out.... where's the crush sleeve? See pictures below, but I'm not seeing the crush sleeve unless its behind that pinion bearing. Also it looks like the yoke already has a Redi-sleeve on it.

 

[Tony 64]

Behind the bearing.

 

[Urambo Tauro]

...Also it looks like the yoke already has a Redi-sleeve on it.

If that's a sleeve (kind of hard to tell from this angle), then you'll want to remove it and install a new one. (A Dremel with a cut-off wheel is helpful for this, but be careful so as to not damage the yoke behind it while cutting.)

 

[t.mcginley.jr]

Ok so I can just take off the extension housing and the crush sleeve should be behind it? I believe there's a big O-ring in there that I should probably replace too while it's apart.

I just ordered that beam-style torque wrench off Amazon. I was hoping Autozone had them for rent but they only stock the click-type.

 

[Gt350HR]

First try and slide the bearing out from it's current place. If it doesn't slide of easily, place a piece of wood 2x4 on the end of the pinion and tap it with a hammer to unseat it. It does have the ability to move backward a bit before contacting the case and it won't do any harm. If that works , behind the bearing will be a small thin sleeve with a bump in the middle. That is the crush sleeve and it will slide off easily. Do the modification I outlined and replace it followed by the bearing , new seal , yoke and nut. When tightening the nut , you may find that an adjustable pipe wrench attached to the yoke will allow you to tighten the nut easier.