Rear End FAQ
05-05-2007, 07:01 PM
#31
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Join Date: Dec 1969
Location: Buffalo, New York
Posts: 10,745
From Randy's Ring and Pinion, a great company to do business with: http://www.ringpinion.com/Default.aspx
"What is the break-in proceedure for a new set of gears?
All new gear sets require a break-in period to prevent damage from overheating. After driving the first 15 or 20 miles it is best to let the differential cool before proceeding. I recommend at least 500 miles before towing. I also recommend towing for very short distances (less than 15 miles) and letting the differential cool before continuing during the first 45 towing miles. This may seem unnecessary but I have seen many differentials damaged from being loaded before the gear set was broken in.
I also recommend changing the gear oil after the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new gear set."
For race cars, most people run them on the jackstands for a few minutes at moderate speed, let them cool down and then go.
Rich
"What is the break-in proceedure for a new set of gears?
All new gear sets require a break-in period to prevent damage from overheating. After driving the first 15 or 20 miles it is best to let the differential cool before proceeding. I recommend at least 500 miles before towing. I also recommend towing for very short distances (less than 15 miles) and letting the differential cool before continuing during the first 45 towing miles. This may seem unnecessary but I have seen many differentials damaged from being loaded before the gear set was broken in.
I also recommend changing the gear oil after the first 500 miles. This will remove any metal particles or phosphorus coating that has come from the new gear set."
For race cars, most people run them on the jackstands for a few minutes at moderate speed, let them cool down and then go.
Rich
06-26-2007, 11:35 PM
#32
Registered User
Join Date: Mar 2001
Location: Shelton, WA
Posts: 954
I have a question that has been on my mind awhile.
What is the strength of rear gears as a function of their ratio (#teeth on ring/pinion); given equal size, materials, etc.
I.E.
4.10 ratio (41 teeth ring/10 teeth pinion) versus
4.11 ratio (37 teeth ring/9 teeth pinion)
I think this information would help people make more educated decisions on gear ratios if they knew the ones that were strongest/weakest and why.
Thanks
What is the strength of rear gears as a function of their ratio (#teeth on ring/pinion); given equal size, materials, etc.
I.E.
4.10 ratio (41 teeth ring/10 teeth pinion) versus
4.11 ratio (37 teeth ring/9 teeth pinion)
I think this information would help people make more educated decisions on gear ratios if they knew the ones that were strongest/weakest and why.
Thanks
06-27-2007, 06:32 AM
#33
Super Moderator
Join Date: Jul 2005
Location: Okemos, MI
Posts: 9,479
Given the same materials and manufacturing process, gears that are physically bigger are stronger.
A stock 4th gen F-body rear end has a 7.5" ring gear. The stock rear end found in 78-87 G-bodies (and some other cars as well) have 8.5" ring gears. 12-bolts have 8.875" ring gears. Ford 9" rears have (you guessed it) 9" ring gears. Dana 60's have 9.75" ring gears.
A given gear ratio dictates that the pinion gear be a given fraction of the size of the ring gear. As your gear ratio increases numerically, the pinion gear gets smaller, and therefore weaker.
So, given the same ring gear size, 3.73s will be stronger than 4.10s.
There are other variables to take into account, since the ring and pinion aren't the only things that can break, but those are the basic guidelines.
A stock 4th gen F-body rear end has a 7.5" ring gear. The stock rear end found in 78-87 G-bodies (and some other cars as well) have 8.5" ring gears. 12-bolts have 8.875" ring gears. Ford 9" rears have (you guessed it) 9" ring gears. Dana 60's have 9.75" ring gears.
A given gear ratio dictates that the pinion gear be a given fraction of the size of the ring gear. As your gear ratio increases numerically, the pinion gear gets smaller, and therefore weaker.
So, given the same ring gear size, 3.73s will be stronger than 4.10s.
There are other variables to take into account, since the ring and pinion aren't the only things that can break, but those are the basic guidelines.
08-08-2007, 03:47 AM
#34
Member
Join Date: May 2003
Location: So Cal
Posts: 236
Given the same materials and manufacturing process, gears that are physically bigger are stronger.
A stock 4th gen F-body rear end has a 7.5" ring gear. The stock rear end found in 78-87 G-bodies (and some other cars as well) have 8.5" ring gears. 12-bolts have 8.875" ring gears. Ford 9" rears have (you guessed it) 9" ring gears. Dana 60's have 9.75" ring gears.
A given gear ratio dictates that the pinion gear be a given fraction of the size of the ring gear. As your gear ratio increases numerically, the pinion gear gets smaller, and therefore weaker.
So, given the same ring gear size, 3.73s will be stronger than 4.10s.
There are other variables to take into account, since the ring and pinion aren't the only things that can break, but those are the basic guidelines.
A stock 4th gen F-body rear end has a 7.5" ring gear. The stock rear end found in 78-87 G-bodies (and some other cars as well) have 8.5" ring gears. 12-bolts have 8.875" ring gears. Ford 9" rears have (you guessed it) 9" ring gears. Dana 60's have 9.75" ring gears.
A given gear ratio dictates that the pinion gear be a given fraction of the size of the ring gear. As your gear ratio increases numerically, the pinion gear gets smaller, and therefore weaker.
So, given the same ring gear size, 3.73s will be stronger than 4.10s.
There are other variables to take into account, since the ring and pinion aren't the only things that can break, but those are the basic guidelines.
08-08-2007, 07:00 AM
#35
Super Moderator
Join Date: Jul 2005
Location: Okemos, MI
Posts: 9,479
DTS sells a Dana 60 rear for the F-body. Strange does too, but everybody tells me to go with DTS. They don't have prices for complete rear ends on their website, but they have a phone number and an email contact form.
http://www.drivetrainspecialists.com/
03-06-2008, 08:26 AM
#37
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Join Date: Jul 2005
Location: Okemos, MI
Posts: 9,479
There are a number of ways. If the rear end is not attached to the engine (i.e. the driveshaft is not connected), just count how many turns of the pinion yoke result in one full turn of the axles. If you can actually measure it in degrees, you can be exact -- otherwise, it's tough to tell the difference between something like a 3.42 and a 3.50 gear.
If the rear end is attached to the car, go out for a drive. Pick a constant speed, and then take note of your speed, RPM, and what gear you're in. Do that a couple times at different speeds and in different gears.
Next, use a calculator like this one. Fill in your information and click Calculate, and then play with the gear ratio box until you find a ratio works with your numbers.
Do a burnout. One tire mark = not posi. Two tires marks = posi.
I have no idea what you are asking. There is nothing transmission-specific in the rear end on an F-body.
If the rear end is attached to the car, go out for a drive. Pick a constant speed, and then take note of your speed, RPM, and what gear you're in. Do that a couple times at different speeds and in different gears.
Next, use a calculator like this one. Fill in your information and click Calculate, and then play with the gear ratio box until you find a ratio works with your numbers.
Do a burnout. One tire mark = not posi. Two tires marks = posi.
I have no idea what you are asking. There is nothing transmission-specific in the rear end on an F-body.
03-06-2008, 04:20 PM
#38
Registered User
Join Date: Feb 2008
Location: Virginia
Posts: 4
There are a number of ways. If the rear end is not attached to the engine (i.e. the driveshaft is not connected), just count how many turns of the pinion yoke result in one full turn of the axles. If you can actually measure it in degrees, you can be exact -- otherwise, it's tough to tell the difference between something like a 3.42 and a 3.50 gear.
If the rear end is attached to the car, go out for a drive. Pick a constant speed, and then take note of your speed, RPM, and what gear you're in. Do that a couple times at different speeds and in different gears.
Next, use a calculator like this one. Fill in your information and click Calculate, and then play with the gear ratio box until you find a ratio works with your numbers.
Do a burnout. One tire mark = not posi. Two tires marks = posi.
I have no idea what you are asking. There is nothing transmission-specific in the rear end on an F-body.
If the rear end is attached to the car, go out for a drive. Pick a constant speed, and then take note of your speed, RPM, and what gear you're in. Do that a couple times at different speeds and in different gears.
Next, use a calculator like this one. Fill in your information and click Calculate, and then play with the gear ratio box until you find a ratio works with your numbers.
Do a burnout. One tire mark = not posi. Two tires marks = posi.
I have no idea what you are asking. There is nothing transmission-specific in the rear end on an F-body.
03-06-2008, 05:28 PM
#39
Super Moderator
Join Date: Jul 2005
Location: Okemos, MI
Posts: 9,479
If the car is as it came from the factory, there are far easier ways to find out what you have.
05-31-2008, 11:55 PM
#40
Registered User
Join Date: Oct 2006
Location: Santa Barbara, Ca
Posts: 273
Just thought I would mention that my 1993 Camaro Z28/A4 has the original posi
rear in it, with 256,000 miles and plenty of abuse. I havent even changed the
fluid - ever. At this point I am afraid to touch it. My wifes 1995 Camaro Z28
toasted the rear end at 130k, about the same time as the 4L60E. We just got
a 1999 Camaro SS to replace the '95 (she was forced into the center divider
by an SUV) and I am swapping a 2.73 axle for the toasted 3.23 axle. The '99
has traction control, the 2000 Z28 rear I got doesnt. I was in the process of
doing the axle/backing plate swap (THIS WEEKEND) and I found this post. Its
good to know that we came to the same conclusion on that. The '99 blew a
pinion seal and lost fluid - so I suggest for people to remove the plug in the
side of the housing and make sure you can touch fluid.
Good info!
Tom
rear in it, with 256,000 miles and plenty of abuse. I havent even changed the
fluid - ever. At this point I am afraid to touch it. My wifes 1995 Camaro Z28
toasted the rear end at 130k, about the same time as the 4L60E. We just got
a 1999 Camaro SS to replace the '95 (she was forced into the center divider
by an SUV) and I am swapping a 2.73 axle for the toasted 3.23 axle. The '99
has traction control, the 2000 Z28 rear I got doesnt. I was in the process of
doing the axle/backing plate swap (THIS WEEKEND) and I found this post. Its
good to know that we came to the same conclusion on that. The '99 blew a
pinion seal and lost fluid - so I suggest for people to remove the plug in the
side of the housing and make sure you can touch fluid.
Good info!
Tom
11-08-2008, 12:33 AM
#41
Registered User
Join Date: Aug 2007
Posts: 573
That depends on the type of posi. I believe that will hold true for all posi's that came from the factory in a 4th gen. Are we talking about a 4th gen? AFAIK, all 4th gen V8 cars had posi's.
I would think that if the transmission is in gear and the clutch is engaged (so that the pinion yoke can't spin), it would be the same.
If the car is as it came from the factory, there are far easier ways to find out what you have.
I would think that if the transmission is in gear and the clutch is engaged (so that the pinion yoke can't spin), it would be the same.
If the car is as it came from the factory, there are far easier ways to find out what you have.
01-06-2010, 02:31 AM
#43
Registered User
Join Date: Jun 2007
Location: Sugar Land(Houston), TX
Posts: 47
Rear ends
How much effort is involved in upgrading to a 10 bolt or a 9 inch Ford? I've had my 10 bolt out of the car for a fuel pump install. There's four large bolts to hold the torque arm to the carrier housing. Also, how about the emergency brake cable and brake backing plates? Any problems keeping it with disk brakes? What about the yoke for the universal joints?
All these questions lead me to believe that upgrading from the 10 bolt should be done by someone who knows the answers.
All these questions lead me to believe that upgrading from the 10 bolt should be done by someone who knows the answers.
01-19-2010, 11:41 AM
#44
Administrator
Join Date: Nov 1998
Location: Hell was full so they sent me to NJ
Posts: 70,650
http://www.injuneer.com/Strange12.html
Depending on your ultimate HP goals, you might also want to consider the Strange (Dana) 60. What HP levels are you looking at, and how is the car used?
Strange 12-bolt:
http://www.injuneer.com/images/photo.../DCP04302a.jpg
Moser 9-inch:
http://www.injuneer.com/images/photo.../DCP03870a.jpg
