rattle from rear when going over bumps
Thread Starter
Member
Joined: Nov 2005
Posts: 332
Likes: 0
From: Southern IN
Car: 1986 IROC Z-28
Engine: Rebuilt Vortec Headded 358SB 9.5:1
Transmission: 700r4, corvette servo, Transgo kit
Axle/Gears: 3.23 POSI
rattle from rear when going over bumps
I recently bought my 86 iroc z with the stock 305 and 126k mi for $2100- the motor burns some oil, but it ran really great. but ive got it in the shop swapping the 305 to my 358 zz4 modeled engine with vortec heads.and keeping the TPI using Edelbrocks High flow runners, and Vortec baseplate.- hoping to come out around 380 horse..
Anyway- when i was driving the car slowly and had the windows down and went over a bump, or railroad tracks i could hear a rattle from the rear of the car, sounds like both sides, and ive hat it in the air ( on a 2 post lift) and shaken it and stuff and cant find anything.. Could the stock wheel spacers be causing my problem?? if so, should i take them off or will my 245/50/r16's rub??
Also- how do i figure out which one of the 3 gear ratio's of posi rear ends GM used for my 86 Iroc??
Thankyou in advace
Anyway- when i was driving the car slowly and had the windows down and went over a bump, or railroad tracks i could hear a rattle from the rear of the car, sounds like both sides, and ive hat it in the air ( on a 2 post lift) and shaken it and stuff and cant find anything.. Could the stock wheel spacers be causing my problem?? if so, should i take them off or will my 245/50/r16's rub??
Also- how do i figure out which one of the 3 gear ratio's of posi rear ends GM used for my 86 Iroc??
Thankyou in advace
Joined: Sep 2005
Posts: 27,953
Likes: 2,463
Car: Yes
Engine: Usually
Transmission: Sometimes
Axle/Gears: Behind me somewhere
If it sounds like coins jingling in your pocket, it's your sway bar end links. Go get poly ones, they even have them at AutoZone for cheap. They make an amazing difference to the feel of the car.
If it sounds like something heavier and duller, it might be disk brake pads.
The only way to know for sure what gears you have is to take off the cover and look. All the "turn the drive shaft and count" methods have too much uncertainty due to operator error, and the "codes" (even if you can find them) will only tell you what gears came in that housing, not whether that housing came in your car, or what gears happen to be in it now. Besides, you just bought the car; the VERY FIRST THING you should be doing, is scheduled maintenance; rear end gear lube is one of those things; so while you're catching up on the past-due maintenance, which requires pulling the rear end cover anyway, make a point of looking at the gears while the cover is off. The tooth count is almost always stamped on the edge of the ring (will look something like 42:13, which is 42 divided by 13, which is 3.23), or if you can't find that, just count the teeth and divide.
If it sounds like something heavier and duller, it might be disk brake pads.
The only way to know for sure what gears you have is to take off the cover and look. All the "turn the drive shaft and count" methods have too much uncertainty due to operator error, and the "codes" (even if you can find them) will only tell you what gears came in that housing, not whether that housing came in your car, or what gears happen to be in it now. Besides, you just bought the car; the VERY FIRST THING you should be doing, is scheduled maintenance; rear end gear lube is one of those things; so while you're catching up on the past-due maintenance, which requires pulling the rear end cover anyway, make a point of looking at the gears while the cover is off. The tooth count is almost always stamped on the edge of the ring (will look something like 42:13, which is 42 divided by 13, which is 3.23), or if you can't find that, just count the teeth and divide.
Thread Starter
Member
Joined: Nov 2005
Posts: 332
Likes: 0
From: Southern IN
Car: 1986 IROC Z-28
Engine: Rebuilt Vortec Headded 358SB 9.5:1
Transmission: 700r4, corvette servo, Transgo kit
Axle/Gears: 3.23 POSI
Originally posted by sofakingdom
If it sounds like coins jingling in your pocket, it's your sway bar end links. Go get poly ones, they even have them at AutoZone for cheap. They make an amazing difference to the feel of the car.
If it sounds like something heavier and duller, it might be disk brake pads.
The only way to know for sure what gears you have is to take off the cover and look. All the "turn the drive shaft and count" methods have too much uncertainty due to operator error, and the "codes" (even if you can find them) will only tell you what gears came in that housing, not whether that housing came in your car, or what gears happen to be in it now. Besides, you just bought the car; the VERY FIRST THING you should be doing, is scheduled maintenance; rear end gear lube is one of those things; so while you're catching up on the past-due maintenance, which requires pulling the rear end cover anyway, make a point of looking at the gears while the cover is off. The tooth count is almost always stamped on the edge of the ring (will look something like 42:13, which is 42 divided by 13, which is 3.23), or if you can't find that, just count the teeth and divide.
If it sounds like coins jingling in your pocket, it's your sway bar end links. Go get poly ones, they even have them at AutoZone for cheap. They make an amazing difference to the feel of the car.
If it sounds like something heavier and duller, it might be disk brake pads.
The only way to know for sure what gears you have is to take off the cover and look. All the "turn the drive shaft and count" methods have too much uncertainty due to operator error, and the "codes" (even if you can find them) will only tell you what gears came in that housing, not whether that housing came in your car, or what gears happen to be in it now. Besides, you just bought the car; the VERY FIRST THING you should be doing, is scheduled maintenance; rear end gear lube is one of those things; so while you're catching up on the past-due maintenance, which requires pulling the rear end cover anyway, make a point of looking at the gears while the cover is off. The tooth count is almost always stamped on the edge of the ring (will look something like 42:13, which is 42 divided by 13, which is 3.23), or if you can't find that, just count the teeth and divide.
I think it might be the sway bushings then- thanks for the help
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