Pinion Gear question

[White Lincoln]

Good day,
I replaced the pinion seal on my Town Car recently, but when I took the car off the jacks and for a test drive, I get this clicking or clunking noise when in reverse. And the drive shaft sounds like it is out of balance, but this is at 5-6 mph. Driving forward does not have the same results. I put the car back up on jacks and checked the parking brake and it was not that. I ran the car in 1st gear on jacks to keep the speed down to 5mph and drive shaft is not turning that much. The clunking is coming from the u-joint / pinion gear area. I also pulled the U-Joints and inspected them and they were in good condition still. I thought I tightened the pinion nut correctly per the notch I made with the pinion gear shaft and the nut, but the more I read, it would seem I have it too tight, as the symptoms are similar to the nut being too tight. I even wondered if I got the diff pinion gears (spider gears) were off a gear, but that would be impossible because you can't put the cross pin in if they were off.

I am going to take the car into Ford cause my back can't take another round of jacking and crawling, but wanted to know more or less what to tell them I think the issue is.

If I did not tighten the pinion nut enough, would it cause the same issues? I didn't see anything about not tightening enough issues.

 

[dDUBb]

On a pinion seal replacement - best practice is to do like you mentioned and mark a notch in the original nut position .. and when re-installing to go just a hair past the mark. Anything more may compromise the pinion depth setting.

 

[MadMikeyL]

I think it’s more likely that you didn’t tighten it enough than that you over tightened it. Did you only replace the seal, or did you have the whole diff apart? If everything was apart, did you replace the crush sleeve? Did you measure the torque required to turn the pinion gear? If you left the carrier in place and only replaced the seal, then the mark method works pretty well, but I usually go just slightly past the mark to crush the sleeve just a tiny bit more to keep enough preload on the bearings.

 

[White Lincoln]

On a pinion seal replacement - best practice is to do like you mentioned and mark a notch in the original nut position .. and when re-installing to go just a hair past the mark. Anything more may compromise the pinion depth setting.

Exactly. I did do that as well, about 1/8" past the mark I made.

 

[White Lincoln]

I think it’s more likely that you didn’t tighten it enough than that you over tightened it. Did you only replace the seal, or did you have the whole diff apart? If everything was apart, did you replace the crush sleeve? Did you measure the torque required to turn the pinion gear? If you left the carrier in place and only replaced the seal, then the mark method works pretty well, but I usually go just slightly past the mark to crush the sleeve just a tiny bit more to keep enough preload on the bearings.

Yes, I only replaced the seal. It was leaking from age and it needed to be replaced.

As for doing the torque thingy, I was trying to figure out how to set my micrometer torque wrench to test the strength and realized you need a Drive Beam Torque Wrench, which I do not have. So I said F-it and went hell bent into the project.

Anyone know what the torque might be for a 95 Town Car differential pinion gear? (that was a joke...)

Just the same, in my mind, I did not tighten it enough. I read somewhere, and maybe it was not related to this, that the torque is about 185 ft/lbs for the nut. I don't think so, but the point being I don't think I tightened it enough.

After saying F-it with the Town Car, I put the Cougar up on ramps yesterday evening, replaced the starter and replaced a broken fog light and by then, I plum had enough of crawling under the damn cars to last several months. Time to just take the car into a shop close to home, hope they don't screw me on the price and just fix the pinion nut.

 

[MadMikeyL]

There isn’t a torque spec for the pinion nut, there is a spec for the torque required to turn the pinion when everything is tightened, which is 8-14in-lbs. However if you only replaced the seal, you can’t check that because you would have to remove the axles and carrier to get an accurate reading, hence the method of making a mark in both the gear and the nut, and going slightly past that. If you did that, it is possible you are a full turn too loose. Either that, or you are a full turn too tight. Either way, I would get under there and try to tighten it some more before bringing it somewhere. If it is too loose now, it’s and easy fix to just tighten it up, and if it is already too tight, then it all has to come apart to replace the crush sleeve anyway, so you really can’t make it any worse by trying.

 

[KevinVarnes]

I usually mark the location rotationally, measure the amount of thread sticking out of the pinion nut with a pair of calipers, and count the turns. Last time I did the pinion seal on the Crown Vic I thought for sure that I had counted the turns on and back off correctly, but a quick check on how much thread was sticking out of the nut confirmed I was still one turn out.

 

[White Lincoln]

From this pic, it looks (to me) as though I need another thread as I recall before I took the nut off. And yes, I replaced the pinion seal AFTER doing the axle bearings and seals. I have never replaced pinion or tranny seals before and I can keep kicking myself in the head for NOT taking a pic before removing the nut. I looked through all my pics and not one of the pinion nut. You can see the marks I made on the shaft and the nut. I tightened it just past the shaft mark.

One thing I forgot to ask is, can I drive this to a garage with the nut being too tight / too lose? It's like 2 miles to the nearest shop. As mentioned, I would like to just do this myself, but my back is getting worse. I still might put it up on ramps and see what do. Thanks everyone.

 

[MadMikeyL]

If it’s too tight, it could damage the bearing, and if it’s too loose, it could damage the gear. The bearing is cheap, but a new ring and pinion, plus the extra labor to set them up properly is not. That’s why I would definitely try to tighten it another turn before anything.

 

[dDUBb]

Here is a factory installed pinion nut for comparison . Tolerance for shim is usually pretty consistent so well assume this to be close to a normal depth.

 

[MadMikeyL]

Yeah, that’s definitely not tightened all the way down.

 

[White Lincoln]

Excellent. I think I will give this another go this weekend if not sooner. But dang, crawling under this car is getting old fast.

I need to talk the wife into letting me get one of these:



So, aside from all of this, would it be wise to put the car up on jacks, crawl under, remove the drive shaft (not drop it, just remove the rear end), tighten the nut a turn, put the drive shaft back on, test the drive shaft by running the car in reverse, forward, etc and repeat until it runs smooth?

 

[White Lincoln]

I found this video (

) that was a lot of help in understanding more about how tight that nut has to be and how to measure the pre-load. This is on the 8.8 rear end, which is what both the Cougar and Town Car have. And yes, I did not tighten that nut near what it needs to be in recalling how I tightened it.

I made a companion tool from a garage door curved door arm. I only had to make the holes a little bigger with my drill press.



Thanks all of you that chimed in for the encouragement in trying this on my own instead of taking it somewhere. I am always afraid a shop is going to pull the BS that "the pinion gear was damaged and we have to replace everything" lie so they can screw me on the price.

I will follow up in a week or so on how this went.

 

[MadMikeyL]

Gotta love home made tools!

 

[Grog6]

I remember custom spark plug wrenches for getting the rear plugs on a chevy monza with a v8; there's a lot of the 70's I don't miss.

 

[White Lincoln]

I remember custom spark plug wrenches for getting the rear plugs on a chevy monza with a v8; there's a lot of the 70's I don't miss.

Mustang 2 with a 302 and having to lift the engine to change the plugs....

 

[White Lincoln]

Gotta love home made tools!

I know, right?!