Differential - 1991 Chevy Caprice 5.0l Automatic
- Thread starter WyrTwister
- Start date
- Status
Hmmmmmm .......
I do not automatically assume the rear brakes are dragging .
Once both sides are up in the air , not hard to spin the tire / wheel , to determine if they are dragging or not .
Thanks ,
I do not automatically assume the rear brakes are dragging .
Once both sides are up in the air , not hard to spin the tire / wheel , to determine if they are dragging or not .
Thanks ,
Originally Posted By: DoubleWasp
75-90 is the spec according to the manual for my 1992 Wagon. I use Amsoil 75-110. No complaints, and ive replaced my seal as well. That thing just went downhill really fast one day. I also changed my diff yokes to a 1350 yoke so I could run an aluminum Chevy SSR driveshaft. That worked wonders in removing vibes from the drivetrain, especially at high speed. Having a factory 3.27 rear, it matters.
I thought 75W90 or straight 90 was SOP from that time period .
Thanks ,
75-90 is the spec according to the manual for my 1992 Wagon. I use Amsoil 75-110. No complaints, and ive replaced my seal as well. That thing just went downhill really fast one day. I also changed my diff yokes to a 1350 yoke so I could run an aluminum Chevy SSR driveshaft. That worked wonders in removing vibes from the drivetrain, especially at high speed. Having a factory 3.27 rear, it matters.
I thought 75W90 or straight 90 was SOP from that time period .
Thanks ,
Originally Posted By: WyrTwister
Hmmmmmm .......
I do not automatically assume the rear brakes are dragging .
Once both sides are up in the air , not hard to spin the tire / wheel , to determine if they are dragging or not .
Thanks ,
When you are dealing with inch pounds, having to overcome the small effort to get wheels spinning will have an effect on your measurement. Don't want to take five extra minutes to do it correctly is your business.
Hmmmmmm .......
I do not automatically assume the rear brakes are dragging .
Once both sides are up in the air , not hard to spin the tire / wheel , to determine if they are dragging or not .
Thanks ,
When you are dealing with inch pounds, having to overcome the small effort to get wheels spinning will have an effect on your measurement. Don't want to take five extra minutes to do it correctly is your business.
Originally Posted By: Tman220
There is no reason replacing a pinion seal will create whine unless the pre-load got goofed up while reassembling. You say you tightened the pinion nut with a 24" breaker bar? How did you know when to stop?
You also have whine on acceleration? I'm willing to bet the cause of this is because you over-tightened the pinion nut, which crushed the crush sleeve slightly more increasing your pinion bearing preload.
oil does not exist that will help this situation.
You need to install a new crush sleeve. You then tighten the pinion nut little by little (this crushes the crush sleeve) and creates the pre-load on your pinion bearings. You need to measure the force in inch/lbs it takes to turn the pinion (wheels off the ground) You are looking for about 15-20 inch/lbs of force to turn the pinion once pre-load is correct. (if carrier is removed you usually want 8-12 inch/lbs on the pinion only with used bearings)
There's quite a bit that goes into all this, I suggest you do some research and get it right, otherwise you will never have a silent diff.
Let me re-iterate, oil does not exist that will fix too much pre-load on the bearings to the point they whine. You may already have destroyed the bearings and races depending on the severity.
OK , I am about to start jacking up the back of the car .
First thing , I plan to check the pre-load , as it presently is . All the bearings , crush ring , ring gear and pinion gear are original to the car . Back cover has never been removed .
I want 15 - 20 inch pounds or 8 - 12 ?
This will be phase I .
Thanks ,
There is no reason replacing a pinion seal will create whine unless the pre-load got goofed up while reassembling. You say you tightened the pinion nut with a 24" breaker bar? How did you know when to stop?
You also have whine on acceleration? I'm willing to bet the cause of this is because you over-tightened the pinion nut, which crushed the crush sleeve slightly more increasing your pinion bearing preload.
oil does not exist that will help this situation.
You need to install a new crush sleeve. You then tighten the pinion nut little by little (this crushes the crush sleeve) and creates the pre-load on your pinion bearings. You need to measure the force in inch/lbs it takes to turn the pinion (wheels off the ground) You are looking for about 15-20 inch/lbs of force to turn the pinion once pre-load is correct. (if carrier is removed you usually want 8-12 inch/lbs on the pinion only with used bearings)
There's quite a bit that goes into all this, I suggest you do some research and get it right, otherwise you will never have a silent diff.
Let me re-iterate, oil does not exist that will fix too much pre-load on the bearings to the point they whine. You may already have destroyed the bearings and races depending on the severity.
OK , I am about to start jacking up the back of the car .
First thing , I plan to check the pre-load , as it presently is . All the bearings , crush ring , ring gear and pinion gear are original to the car . Back cover has never been removed .
I want 15 - 20 inch pounds or 8 - 12 ?
This will be phase I .
Thanks ,
Originally Posted By: Tman220
There is no reason replacing a pinion seal will create whine unless the pre-load got goofed up while reassembling. You say you tightened the pinion nut with a 24" breaker bar? How did you know when to stop?
The pinion seal being replaced was the cause.
There is no reason replacing a pinion seal will create whine unless the pre-load got goofed up while reassembling. You say you tightened the pinion nut with a 24" breaker bar? How did you know when to stop?
The pinion seal being replaced was the cause.
Well , I spent 1 - 1-1/2 hours removing the Rear brake drums . They had never been removed . The drums were rusted to the axle " hub " . The " star wheel " would not turn . Plus all the hammering started the LR wheel cylinder to leaking . Not a fun time . :-(
Got the drive shaft off . My el-cheep-o inch pound torque wrench only goes down to 20 inch pounds . It did not click when rotating the pinion yoke . If I held the yoke by hand , it clicks the torque wrench . So , I guess the pinion nut is not too tight ?
Screwed out the fill plug & no oil ran out . Added about 6 ounces of Valvoline 85W140 gear oil .
That is all I am going to do to it today /
Going to test drive it after I clean up some & feed my face .
Thanks ,
Got the drive shaft off . My el-cheep-o inch pound torque wrench only goes down to 20 inch pounds . It did not click when rotating the pinion yoke . If I held the yoke by hand , it clicks the torque wrench . So , I guess the pinion nut is not too tight ?
Screwed out the fill plug & no oil ran out . Added about 6 ounces of Valvoline 85W140 gear oil .
That is all I am going to do to it today /
Going to test drive it after I clean up some & feed my face .
Thanks ,
Originally Posted By: CT8
Originally Posted By: Tman220
There is no reason replacing a pinion seal will create whine unless the pre-load got goofed up while reassembling. You say you tightened the pinion nut with a 24" breaker bar? How did you know when to stop?
The pinion seal being replaced was the cause.
Care to elaborate further on its causation in the mechanism of whine generation, other than Tman's position of excessive pinion pre-load among others , which OP may have demonstrated as not quite valid ?
Originally Posted By: Tman220
There is no reason replacing a pinion seal will create whine unless the pre-load got goofed up while reassembling. You say you tightened the pinion nut with a 24" breaker bar? How did you know when to stop?
The pinion seal being replaced was the cause.
Care to elaborate further on its causation in the mechanism of whine generation, other than Tman's position of excessive pinion pre-load among others , which OP may have demonstrated as not quite valid ?
Maybe the pinion nut is not tight enough ?
Originally Posted By: WyrTwister
Well , I spent 1 - 1-1/2 hours removing the Rear brake drums . They had never been removed . The drums were rusted to the axle " hub " . The " star wheel " would not turn . Plus all the hammering started the LR wheel cylinder to leaking . Not a fun time . :-(
Got the drive shaft off . My el-cheep-o inch pound torque wrench only goes down to 20 inch pounds . It did not click when rotating the pinion yoke . If I held the yoke by hand , it clicks the torque wrench . So , I guess the pinion nut is not too tight ?
Screwed out the fill plug & no oil ran out . Added about 6 ounces of Valvoline 85W140 gear oil .
That is all I am going to do to it today /
Going to test drive it after I clean up some & feed my face .
Thanks ,
Hammering on the drums does not cause wheel cylinders to leak. You likely killed two birds with one stone since it appears that your drum brakes were long overdue for service, IE frozen drums, star wheels and leaky wheel cylinders.
Well , I spent 1 - 1-1/2 hours removing the Rear brake drums . They had never been removed . The drums were rusted to the axle " hub " . The " star wheel " would not turn . Plus all the hammering started the LR wheel cylinder to leaking . Not a fun time . :-(
Got the drive shaft off . My el-cheep-o inch pound torque wrench only goes down to 20 inch pounds . It did not click when rotating the pinion yoke . If I held the yoke by hand , it clicks the torque wrench . So , I guess the pinion nut is not too tight ?
Screwed out the fill plug & no oil ran out . Added about 6 ounces of Valvoline 85W140 gear oil .
That is all I am going to do to it today /
Going to test drive it after I clean up some & feed my face .
Thanks ,
Hammering on the drums does not cause wheel cylinders to leak. You likely killed two birds with one stone since it appears that your drum brakes were long overdue for service, IE frozen drums, star wheels and leaky wheel cylinders.
Last edited:
Perhaps you are right . But I had to beat pretty enthusiastically on the drums on a 1996 Chevy Lumina Sedan & ended up with with a leaky wheel cylinder .
On the other hand , I discovered a broken spring on the opposite side .
The drums did not have a ridge at the " rim " . Only a slight taper . So very little wear . Shoes had quite a bit of friction material on them .
All in all , I had much rather work on disc brakes . Drum brakes have all the springs & widgets to get back together correctly . Always a chore putting it all back together . :-(
Thanks ,
On the other hand , I discovered a broken spring on the opposite side .
The drums did not have a ridge at the " rim " . Only a slight taper . So very little wear . Shoes had quite a bit of friction material on them .
All in all , I had much rather work on disc brakes . Drum brakes have all the springs & widgets to get back together correctly . Always a chore putting it all back together . :-(
Thanks ,
- Status
Similar threads
