Question : 4t60e differential carrier

[fbody_mike]

Hello everyone!

I have a 99 Chevy Lumina 3.1L with a 4t60e with about 210K on the clock. Recently I have tried to solve a snap noise from the drivetrain. In doing so I replaced almost all of the suspension (worn and needed it anyway) as well as the CV shafts (which were in decent shape despite the mileage). Anyhow the snapping noise that would happen on hard acceleration from a dead stop, or hard braking has turned into a bad vibration at speeds above 30 MPH.

I put the car up on stands and ran the car in gear to try to find the problem. If only one wheel (the passenger) is spinning there will be no vibration and everything is well. As soon as the speed is high enough both tires will start to spin the whole motor and transmission assembly starts to vibrate badly. The car still shifts fine, and the trans does not slip.

This has led me to think that the differential is bad, especially since I systematically elimanted the other elements by throwing new parts at it. My question is how to remove the differential without dropping the trans out of the car. Can I simply pull the right side CV shaft and differential housing cover then just pull the carrier out?

Thanks,

Mike

[95SleeperAcheiva]

http://60degreev6.com/forum/f75/3-73-final-drive-instructions-t25035

Chase that link. halfway through it tells you how to pull one with tranny in car.

Also, not to be redundant, check and make sure your calipers ain't locked up. I've seen driveline vibration from one locked caliper with badly warped rotor.

Also, check your mounts, the engine and trans maybe sitting out of alignment due to broken/sagging mounts. This includes checking your subframe mounts.

[3400-95-Modified]

Um, the odds of a diff causing vibration is very slim... Have you checked the ballance on your tires, or something with the axles?

Do you know what a FWD carrier looks like? its nothing like a RWD setup so thats why I say the odds of it causing the vibration is slim.

[fbody_mike]

Thanks for the tips and link.

I am this point of blaming the differential because I have replaced the trans and motor mounts, hubs, tie rod ends, ball joints, struts, both CV shafts, and strut mounts. I have also carefully inspected the rotor and calipers and run the whole thing with the tires removed (I used lug nuts to keep the rotor in place). This whole thing has changed from a repair to a challenge. The differential seems to be an easy thing to check before pulling the trans from the car.

Oh and I will definetly post a pic of whatever I find broken. Thats if anything is broken.

[fbody_mike]

Well I pulled the diff, and nothing was wrong there. It did not even look too worn for as many miles as it has. But I did find the source of the bad vibration when I took everything apart. My month old CV shaft that I bought from NAPA were shot. Replaced the CV shafts and the vibration went away. I did not think of really looking at the CV shafts because they were new. Anyhow I do not trust the brand that NAPA carries so I bought new ones from a competitor and NAPA gave me a full refund. That snap noise is still there though, maybe it is a brake caliper.

[95SleeperAcheiva]

check the control arm bushings, they tend to make a wierd knock noise. They like to push out if you have the "puck" design. oem's are fairly cheap, like $35 a set, and I think energy suspension makes a urethane set. for roughly the same price.

[fbody_mike]

check the control arm bushings, they tend to make a wierd knock noise. They like to push out if you have the "puck" design. oem's are fairly cheap, like $35 a set, and I think energy suspension makes a urethane set. for roughly the same price.

BINGO! Front control arm bushing on the passenger side was the noisey piece. No more noise and since all the parts are new it rides and handles great!

THANKS!