pinion depth and backlash
3/12/08, 04:57 PM
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pinion depth and backlash
Im going to install 3.73 ring and pinion but there is information i need that i couldnt manage to find. The pinion depth and its backlash. What are they?
The shop guy asked for them and i need them asap. Also it would be great if any1 can give me a link to a how to do guide for installing 3.73 gears.
Thanks
The shop guy asked for them and i need them asap. Also it would be great if any1 can give me a link to a how to do guide for installing 3.73 gears.
Thanks
3/12/08, 06:23 PM
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Be careful
If the “shop guy” is asking you for this information, do you really want him setting up your gears? A competent rear end guy should have this information readily available.
Most mechanics cannot set rear end gears up properly. This is not a job for the average Joe Wrench. It is imperative it be done right. Or the gear set will chew itself up, it might not happen for some thousands of miles, but if they are not right, they will chew themselves up.
Most mechanics cannot set rear end gears up properly. This is not a job for the average Joe Wrench. It is imperative it be done right. Or the gear set will chew itself up, it might not happen for some thousands of miles, but if they are not right, they will chew themselves up.
3/13/08, 05:35 PM
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Its not that bad.....MHD...Master head distance. The distance from the head of the pinion gear to the centerline of the axle. You usually need a special tool to measure this distance. An aftermarket gear set should include this spec. If you are using Ford gears then you can just use the same shim that is on the stock pinion. That info is straight from Ford Tech... Backlash is the space between the gears on the ring and the pinion when you hold one and move the other. The best thing to do is measure the backlash on the stock gearset before you remove it. A very important part of installing gears is the preload on the pinion crush sleeve. If you have heard people complain about clunking when they take their foot off the gas it is usually the pre load to loose. The torque required to set the proper preload can be up around 150 ft/lbs or greater. The preload is measured in inch/pounds. How much it takes to move the pinion when you use an inch/pound torque wrench. If your shop guy does not know about this information I would find someone else. Ask him some qestions.......
Last edited by Garyalpusa; 3/13/08 at 05:36 PM. Reason: words
3/13/08, 05:58 PM
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Its not that bad.....MHD...Master head distance. The distance from the head of the pinion gear to the centerline of the axle. You usually need a special tool to measure this distance. An aftermarket gear set should include this spec. If you are using Ford gears then you can just use the same shim that is on the stock pinion. That info is straight from Ford Tech... Backlash is the space between the gears on the ring and the pinion when you hold one and move the other. The best thing to do is measure the backlash on the stock gearset before you remove it. A very important part of installing gears is the preload on the pinion crush sleeve. If you have heard people complain about clunking when they take their foot off the gas it is usually the pre load to loose. The torque required to set the proper preload can be up around 150 ft/lbs or greater. The preload is measured in inch/pounds. How much it takes to move the pinion when you use an inch/pound torque wrench. If your shop guy does not know about this information I would find someone else. Ask him some qestions.......
The preload is 150 foot/lbs not inch/lbs. I am sure it is a typo!! Or at least that was I was told!!
Scott
Last edited by 70MACH1OWNER; 3/13/08 at 06:34 PM.
3/13/08, 08:01 PM
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Garyalpusa is right. You'll need at least 140 lb/ft torque to start to crush the crush sleeve to meet minimun preload on pinion bearings. After that you turn the pinion flange nut smoothly with an inch/pound torque wrench (dial or beam style) to read pinion preload. Alternately tighten nut in small increments and recheck until you get 8-14lb/in on used bearings or 16-28lb/in on new bearings.
3/13/08, 08:37 PM
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I have a question.Since i am trying to figure out what is causing my clunk,would an incorrect pinion load be visible opening the rear end?I really have no clue what's going on in there or what to look for.
I have a few thousand miles on the new gears,and the shop told me the clunk was from my true trac grabbing.
.I can get a clunk on letting off gas fast in 4th gear just cruising..
I have a few thousand miles on the new gears,and the shop told me the clunk was from my true trac grabbing..I can get a clunk on letting off gas fast in 4th gear just cruising..
Last edited by Bandit1; 3/13/08 at 08:39 PM.
3/13/08, 09:59 PM
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The only way I know to check the pinion preload would be to remove the carrier/ring gear assy, remove the drive-shaft from the pinion flange and check turning torque with an in/lb torque wrench as stated in my previous reply. It is also possible when gears were installed the backlash is either excessive or they didn't add an extra 0.006" to each carrier side bearing to preload those bearings as well. So the carrier will shift slightly increasing the backlash between accel and decel movements. I don't think the trac-loc would be the problem. They said grabbing. Grabbing what? The trac-loc is holding in a straight ahead position and releases on turns. Was that grabbing comment just verbal when you complained or did they actually recheck their settings? Borrow any Ford service manual from newer mustang's, ranger's or f-series trucks and they'll have good info on how 8.8 diffs are troubleshot and repaired. It's worth reading.
Last edited by Lime GT; 3/14/08 at 05:51 PM. Reason: carrier side bearing preload spec corrected
3/14/08, 05:58 AM
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Thanks very much.Since i don't put alot of miles on the stang,the install was over a year ago,so i mentioned it to them that long ago,and no they did not inspect it again.The other problem was that i did a few mods at nearly the same time and have heard that the stock uca's can have some play in them or maybe even my aftermarket lcas.I have had some clunk back there since purchase of the car,but it seems worse now.I don't know if anything else can cause a similar symptom,or what to do exactly at this point..but very good info.Thanks again,and hope i am not too off topic,but it really bugs me after all this time.
Last edited by Bandit1; 3/14/08 at 06:02 AM.
3/14/08, 07:55 AM
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[RANT ON]
If you randomly have 100 “professionals” from anywhere around the US set up rear end gears, at least 95 of them will not be perfect.
I am so sick and tired of guys talking about changing gears like changing tires they are very different. Setting up rear end gears is really more of an art than a science. Finding a guy who does it well is hard to do, yet absolutely critical if you intend to keep your car long term.
Almost all factory rear end gear sets will easily go 200,000 miles, with no issues. Most aftermarket gear sets set up by the “average” mechanic won’t make it 20,000 miles.
I have set up my own rear end gears and I’ve paid to have it done, it is a pain in the *** to get right. Most guys doing it settle for good enough.
Ring and pinion gear setup is very unforgiving, If it is not perfect it will still “work”, it will just be banging and chewing itself up. It almost always takes more than 1000 miles and generally less than 12000 miles to destroy a less than perfectly assembled set of rear end gears and bearings. A crappy job generally doesn’t result in failure soon enough to be of any consequence to the offending assembler.
Please if you are going to have someone “change” your gears, make **** sure they know exactly what they are doing. Ask them to take pictures (or let you take them) of your Pattern Check for your records. If they are opposed to that much scrutiny, I suggest you don’t want them doing your gears.
[RANT OFF]
Here is some excellent information Ford 9 Inch Rebuild/Gear Setup:
http://www.ford-trucks.com/article/i...ear_Setup.html
24. Paint All Ring Gear Teeth, Both Sides, With Gear Marking Compound (Usually A White Type Of Grease). Put Force On Ring Gear In Either Direction (Small Rubber Pad Pressed Against Ring Gear Teeth Works Well For This). Spin Pinion/Flange Back And Forth, 10 Or 20 Times, Ensuring 5 Or 6 Ring Gear Teeth Mesh With Pinion Gear Teeth. Release Force On Ring Gear And Rotate It To A Point Where Previously Meshed Teeth (Pattern In Grease) Can Be Seen. Pattern Should Look Like Correct Mesh Pattern In Picture http://images.ford-trucks.com/articles/9inch/GEARS.jpg
25. Repeat Procedure, Forcing Ring Gear In Opposite Direction. Check Pattern Again. Both Patterns Should Be In Center Of Tooth And Not Running Off The Edge Of Any Teeth. Pattern Can Be Checked At Various Locations On Ring Gear To Ensure Patterns Are The Same Over Entire Ring Gear. Doing This Will Also Ensure Ring Gear Is Seated Correctly On Differential And Runout On Ring Gear Is Acceptable.
26. If Pattern Is Not Correct, In Both Directions, Pinion Assembly Must Be Removed And A Different Shim Must Be Installed. You Should Only Add/Subtract .002 Inches Of Shim At The Most When Changing The Shim(S) Thickness The First Time. Thicker Shims Can Be Added The Second Time, Depending Upon How Much The Pattern Changes. It Takes Some Practice To Determine How Much Shim To Add/Subtract. Pinion Assembly Must Be Then Re-installed And Side Adjusters Set Up Again So That Backlash Is Once Again .008.
27. Repeat Steps 24-26 Until Pattern Is Correct. This Is The Hardest Part Of Rebuilding A Rear End Assembly. It May Take Many Tries Or Even Days To Get It Right. Be Patient If It Is Your First Time.
Like I said, most guys you pay to do this for you will not do it right!
Two good pictures of the mesh pattern process:
http://www.blackgto.com/jeep/drive.jpg
http://www.blackgto.com/jeep/coast.jpg
From:
http://www.jeepforum.com/forum/showthread.php?t=491890
If you randomly have 100 “professionals” from anywhere around the US set up rear end gears, at least 95 of them will not be perfect.
I am so sick and tired of guys talking about changing gears like changing tires they are very different. Setting up rear end gears is really more of an art than a science. Finding a guy who does it well is hard to do, yet absolutely critical if you intend to keep your car long term.
Almost all factory rear end gear sets will easily go 200,000 miles, with no issues. Most aftermarket gear sets set up by the “average” mechanic won’t make it 20,000 miles.
I have set up my own rear end gears and I’ve paid to have it done, it is a pain in the *** to get right. Most guys doing it settle for good enough.
Ring and pinion gear setup is very unforgiving, If it is not perfect it will still “work”, it will just be banging and chewing itself up. It almost always takes more than 1000 miles and generally less than 12000 miles to destroy a less than perfectly assembled set of rear end gears and bearings. A crappy job generally doesn’t result in failure soon enough to be of any consequence to the offending assembler.
Please if you are going to have someone “change” your gears, make **** sure they know exactly what they are doing. Ask them to take pictures (or let you take them) of your Pattern Check for your records. If they are opposed to that much scrutiny, I suggest you don’t want them doing your gears.
[RANT OFF]
Here is some excellent information Ford 9 Inch Rebuild/Gear Setup:
http://www.ford-trucks.com/article/i...ear_Setup.html
24. Paint All Ring Gear Teeth, Both Sides, With Gear Marking Compound (Usually A White Type Of Grease). Put Force On Ring Gear In Either Direction (Small Rubber Pad Pressed Against Ring Gear Teeth Works Well For This). Spin Pinion/Flange Back And Forth, 10 Or 20 Times, Ensuring 5 Or 6 Ring Gear Teeth Mesh With Pinion Gear Teeth. Release Force On Ring Gear And Rotate It To A Point Where Previously Meshed Teeth (Pattern In Grease) Can Be Seen. Pattern Should Look Like Correct Mesh Pattern In Picture http://images.ford-trucks.com/articles/9inch/GEARS.jpg
25. Repeat Procedure, Forcing Ring Gear In Opposite Direction. Check Pattern Again. Both Patterns Should Be In Center Of Tooth And Not Running Off The Edge Of Any Teeth. Pattern Can Be Checked At Various Locations On Ring Gear To Ensure Patterns Are The Same Over Entire Ring Gear. Doing This Will Also Ensure Ring Gear Is Seated Correctly On Differential And Runout On Ring Gear Is Acceptable.
26. If Pattern Is Not Correct, In Both Directions, Pinion Assembly Must Be Removed And A Different Shim Must Be Installed. You Should Only Add/Subtract .002 Inches Of Shim At The Most When Changing The Shim(S) Thickness The First Time. Thicker Shims Can Be Added The Second Time, Depending Upon How Much The Pattern Changes. It Takes Some Practice To Determine How Much Shim To Add/Subtract. Pinion Assembly Must Be Then Re-installed And Side Adjusters Set Up Again So That Backlash Is Once Again .008.
27. Repeat Steps 24-26 Until Pattern Is Correct. This Is The Hardest Part Of Rebuilding A Rear End Assembly. It May Take Many Tries Or Even Days To Get It Right. Be Patient If It Is Your First Time.
Like I said, most guys you pay to do this for you will not do it right!
Two good pictures of the mesh pattern process:
http://www.blackgto.com/jeep/drive.jpg
http://www.blackgto.com/jeep/coast.jpg
From:
http://www.jeepforum.com/forum/showthread.php?t=491890
Last edited by Black GT500; 3/14/08 at 07:59 AM.
3/14/08, 08:54 AM
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Black GT 500,
I agree with you 100 %.I used to work at a truck repair facility that had a parts, service and rebuild department. I often listened to and observed mechanics in the rebuild department cry about having difficulty acheiving an acceptable pattern and these were mechanics who did this on a regular basis. Quite often these jobs would comeback because of excessive gear whine. Along the same line of thought. What is your opinion as to the ease of replacing the pinion flange and getting the pinion bearing preload right without removing the axle shafts and diff case?
Robert
I agree with you 100 %.I used to work at a truck repair facility that had a parts, service and rebuild department. I often listened to and observed mechanics in the rebuild department cry about having difficulty acheiving an acceptable pattern and these were mechanics who did this on a regular basis. Quite often these jobs would comeback because of excessive gear whine. Along the same line of thought. What is your opinion as to the ease of replacing the pinion flange and getting the pinion bearing preload right without removing the axle shafts and diff case?
Robert
Last edited by shaftmasters; 3/14/08 at 11:22 AM.
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