Tech question. Last year I swapped in some 2.75 in my galaxie. But after a while I just determined that my manual car was too heavy for that highway gear. So I swapped back in the original 3.50 third member that was in the car. It was fine when I pulled it last year. The ONLY thing I did was pull the pinion yoke and replace the old pinion seal. I did this by counting the turns out. Putting it back in the same with 1/8 extra and then checking the spinning torque with a beam Tq wrench. Was a little on the high side but in spec. I dont remember the exact number. Ive done this successfully before on GM rear ends to change the seal. Well first test drive today went back. Everything is normal under power. But as soon as you start coasting it whines bad. If you push the clutch in or have it in neutral no noise. But if it’s in gear and coasting it makes noise. Is this noise on the coast side indicative of that pinion preload being too tight or too loose? Which one?
Isn't there a crush sleeve that is supposed to be replaced any time the pinion nut is removed to get the proper pre-load?
Technically yes. However you will find all kinds of people who have changed the seal and not replaced the crush sleeve. Just put it back in how it was, and check the rotating torque. Ive done it before, this time it may not have worked out for me. I found another thread on here with a noise trouble shooting chart. Noise: Howl while decelerating (gears previously quiet) Cause: Loose pinion bearing preload If thats the case before I do anything dramatic Im just going to tighten it down a little more, recheck it and see if the noise goes away. Maybe the new seal was tight and causing an erroneous reading.
On GMs, it's a pain to get the pinion out to replace the crush sleeve. On the 9", it's easy! Just remove the 5 bolts and pull the whole pinion and support out, and overhaul it. Put it back with the same shim (between support and main case), and it should be fine. Bonus....with a new sleeve, you can get the pinion nut as tight as it needs to be.
"Putting it back in the same with 1/8 extra" Why did you go 1/8 extra? You have probably crushed the sleeve more, which throws the preload off
Ford service manuals weren't written when all the 9" rears were decades old, and the crush sleeves were worn out from the bearings spinning.... crush sleeves don't cost much.
True but I would presume a differential decades old would be overhauled before installation. Ford manual calls for 1/4 turn past marks before nut removal. Joe
No telling what's in there. I just replace the sleeve as a matter of course. Since he's having problems, it might be a good idea to try something different than what he did the first time?
Right on Like you were referring, cheap insurance to know it's correct. The service manual procedure can be followed if you know it's set up right the first time. Joe
I'm with Gene... that extra turn might have made trouble. I've also changed the seal and returned the nut to exactly the same spot on an old Toyota axle with complete satisfaction.
When I did this a while back on a GM rear all the old dealership techs said that that is the way to do it.
I was just watching a video of a guy doing that. I was a bit leery, because I assumed the preload calculation with the torque wrench included it spinning the ring gear. So you can set the proload with just the pinion section on a bench? I would have absolutely done that. I didnt know that. Honestly it wasnt leaking, but its from a 64 galaxie and it had some sort of counter weight on the pinion yoke. Suppoesedly it was a comfort option on big cars. It was broken and free spinning so I wanted to get it off before I reinstalled it. That necessitated removing the yoke. I tossed in a seal just because.
Yes, you can do it with the pinion support of of the car, on a bench. 10-14 in lbs torque for used bearings, new seal, for pinion preload torque. That's from the 1965 shop manual.
Yes, pinion bearing preload is just rotating the pinion with no contact with the ring gear. On a 9 inch it's easy with just the pinion support out of the case. A dial type torque wrench is much easier watching the breakaway value and then the rotating value. That can be hard to watch with a beam type.
I went from a 3.08 gear to a 3.55 in a 8.8 and I re used the same crush sleeve.... 40,000 miles later and still no problems... Guess I got lucky....
Like others have said, remove the pinion assembly, get a new crush sleeve and seal, and reassemble. I normally clamp the u-joint flange in a large vise and tighten the pinion nut until I get some preload on the bearings. I check the preload by rotating the pinion housing. However, I've done a lot of 9 in differentials. The correct way to do it is to lightly clamp the housing in a vise and use a torque wrench to turn the pinion. You want to measure turning torque, not start up torque. Also, the pinion nut will get very hard to turn as you just start to crush the crush sleeve. I do mean very hard. You have to keep going until you get the correct preload. It does get a bit easier to turn once the sleeve begins to crush.
Crush sleeves do not typically wear out in a 9" rear, they are in between the inner races where they should not be getting a lot of rotation- unless the assembly comes loose. It is common practice for high performance use, especially with a manual trans, to install a crush sleeve, torque it up to correct preload, then remove the crush sleeve, measure it and replace it with a solid spacer that is the same thickness as the crushed sleeve, so it can't compress and throw the preload off- which is probably what happened by going "1/8 extra"
I am not sure if it will matter too much, but 3.50 ratio is semi-hunting and should be timed. Good assurance would be to pull the center section and mark the gears before pulling the pinion assembly so it can be returned to it's original mesh.
Very good point- anything that changes the original "used" pattern can cause a howler. Gears that are set up purposely "tight" for manual trans drag race use will usually be howlers- but the open headers help with that lol...
It sounds to me like the pinion is not tight enough and it’s possibly floating back-and-forth slightly. If I do them that way I hit them with an impact and put them back on just until the nut stops. I would bet that pinion is loose.
Well the plot thickens a little bit. I got back down under it. There was definetly more play back and for in the pinion than my other one. IDK how I didnt notice that before. I pulled the pinion section. That was a bear in and of itself. But when I got it out and put in in the vice to spin it, it looks like its correct. It spins freely at about 12 in lbs. So now I dont know what to do. Maybe the cheapy beam tq wrench just sucks from HF. Someone on a ford 9" facebook page suggested that maybe I overtighened it in the first place and moved the pinion gear farther away from the ring gear. Also unfortunetely I didnt notice that hunting thing before I removed it. So thats out the window. Im really mad at myself because I finally have it scheduled to get the front end aligned on wednesday, and it seems like its dead in the water right now. I dont have time to wait for a part from amazon. Im trying to find a part number for a crush sleeve at a local parts store but striking out so far. Im sure there is one, I am just struggling to find it.
you should be able to find the timing mark on the gears, usually a line ground in, and a dab of paint. But usually not a big source of noise, especially on the partially non hunting ratios. Crush sleeves don't wear out, but they seem to be worn out a bit too much whenever I've tried to use one again. On my go fast stuff, I use a solid spacer...
It doesn't work that way, overtightening will crush the sleeve too much and pull the bearings closer together slightly, affecting bearing preload. Adding shims between the pinion carrier and main case will move the pinion away from the ring gear, affecting gear pattern. Seems you did overtighten it with that 1/8 extra thing recommended by the GM mechanics
Oh FWIW, I just went outside and gave it one more look. My stupid cheap beam tq wrench starts at like 8 inlbs. Not zero. It is pretty dainty. Probably had something laying on top of it in my tool box for months. So thats part of the problem. I cant get an accurate reading. It gets from that reading to like 12-13 inlbs. But you cant trust that reading. Who knows if its 5 in lbs or more. If the beam is bent slightly everything is out the window.
That 1/8 extra deal is the problem, and now the crush sleeve has been compromised- it won't spring back, you need to start from scratch with a new crush sleeve
If anything has been changed in the assembly, i.e. new bearing etc., a new sleeve is required, they don't spring back once crushed. If one carefully does it, without over-tightening, you can replace the seal and get away with leaving the crush sleeve- but that 1/8 extra thing screwed the pooch
Yeah I am going to. IDK if the extra 1/8th was the problem. Someone else earlier said the Ford manual says to go 1/4 past. 100% honestly I think I got the count wrong and was a full turn or so short not an 1/8" past. If it was too tight I wouldnt have had the slop that I had with it installed. It looks like 8.8 and 9" crush sleeves are the same. Dorman makes them, in stock at autozone. Ill go get that and another torque wrench. I wish I could find a dial wrench on short notice but nobody locally sells one that I can see.
Replacing a seal in the car gives you an imperfect procedure at best. I have never done this turn count deal, but have had good luck by using a good beam torque wrench when loosening the nut, recording the breakaway torque, and pull it back up to the same torque when replacing the nut, so it doesn't additionally crush the sleeve. I usually also lightly stake the nut to the pinion shaft when done. You can look in either the factory manual, or a period Motor Manual which has a copy of the factory stuff to properly adjust the preload with a new crush sleeve, pretty easy if you follow the factory directions- forget about 1/8 and 1/4 and all that stuff
So, I'm a bit confused about some things you are saying. Are you saying there is play in the pinion bearings? If there is you definitely didn't go far enough with the pinion nut. You have to start putting preload on once you have zero play in the pinion bearings. If your torque wrench is a bending beam type with a pointer, all you have to do to zero it is bend the pointer until it reads zero. It's the movement of the beam (bending) that calibrates the wrench. The pointer only tells you where zero is.
If that preload is loose like it sounds like you are describing that is most likely your problem. It being a little tight as long as it doesn’t wipe out the bearings will not hurt anything. It will not change the pattern by being a little tight.
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