CV shaft grinding/vibrating in 4th gear?

[clark]

EDIT: PROBLEM FOUND!!

has anyone had CV shafts that clunk or grind? how about cv shafts or rear bearings that cause a thump while coasting in neutral?

Problem: i've replaced the subframe bushings COMPLETELY with urethane (bushings honestly weren't in that bad condition) but i STILL have a clunk.

although most of the clunk has subsided and it is a MUCH better driving experience and very predictable now.

but i STILL have a clunk when going into gear and a ridiculous vibration/grinding when coasting and decel in 4th gear only. accelerating in 4th is fine.

1st, 2nd, 3rd gear are all fine on acceleration, coast, and decel. 5th is just great too which is what i do most of my driving in thank god.

i personally think it's my CV shafts. to my knowledge they have not been replaced. NONE of the boots are leaking and they all appear to be in good condition visually.

i just don't exaclty know how to inspect them, i need some guidance from you guys.

what i really want to know is if anyone has rebuilt them OR if anyone has similar symptoms and if you could suggest anything to check.

i also think it may be related to a CV shaft problem because when i coast in neutral at lower speeds i have a "thump thump thump" coming from the ear that gets slower as the car slows down. so a rotational thump that i think is the cv shafts or maybe a bearing.

any suggestions on how to troubleshoot a bad CV shaft? is that a sign that they are going bad?

the fact that it hapens mostly in 4th does help because that means basically the drivetrain/tranny is at a 1:1 ratio. but UGH wtf is it!

dont' tell me to search because this problem can be worded in a million ways and i've already tried with not much luck.

alright guys, have at it, i'll appreciate any feedback. throw some ideas out there guys.

Chassis: S13 coupe
Mileage: 186,000

Differential was completely overhauled with an S15 helical installed professionally

subframe bushings have been replaced with energy suspension bushings (the right way, pics to prove)

1pc steel driveshaft custom made

rear 5-lug conversion from NA z32. mileage unknown

stance coils

new tires, mounted/balanced professionally

here's pics of the subframe bushing install so noone says to use subframe spacers to get rid of my clunk.

http://i198.photobucket.com/albums/aa231/unicoladron/IMG_2277.jpg
http://i198.photobucket.com/albums/aa231/unicoladron/IMG_2278.jpg

snug :)
http://i198.photobucket.com/albums/aa231/unicoladron/IMG_2279.jpg

yes kids, if you are using the ES S14 subframe bushing replacements, leave the metal shell in the subframe:
http://i198.photobucket.com/albums/aa231/unicoladron/IMG_2281.jpg

actually wasn't that bad:
http://i198.photobucket.com/albums/aa231/unicoladron/IMG_2282.jpg

all done:
http://i198.photobucket.com/albums/aa231/unicoladron/IMG_2283.jpg

[clark]

cripes, noone has had this problem?

forgot to mention: the grinding vibrating in 4th gear while decelerating goes away below 42mph. very odd.

[clark]

i can't believe noone has this problem!

btw, it's ALWAYS been there, i'm just finally getting sick of it/complaining about it.

someone has had to have this problem

[track bound]

I have that exact problem. I think its the transmission.

[s13boy89]

my drive shaft does it sometimes

[DaPCWiz]

I know its a shot in the dark, but wheel bearing? if its worn, certain loads could be causing it to thump....

[singlecamcammed240]

mine does it too. the car drives fine besides that. so i dont worry about it. i thought it was because of my stock 2 piece drive shaft. i guess not though. i have a welded rear end and a torn cv shaft boot and aluminum sub frame bushings

[clark]

thanks for the replies guys, all things i've already thought about.

after some more research it COULD be the pilot bearing for my tranny. i actually did NOT replace it when replacing my clutch and i'm kicking my self now.

anyone else wanna chime in about the symptoms of CV shafts going bad? or symptoms of bad wheel bearings?

when jacked up the wheels don't wobble. i've replaced wheel bearings before for this reason, but maybe this is like a ninja bad wheel bearing.

[track bound]

I am still thinking transmission on my car. Everything else has been changed and I thought axle perhaps but I don't see it. How ever when I took the driveshaft out, the splined shaft coming out of the transmission had alot of play, up down side to side

[clark]

well since it's nice out, i jacked the car up and slid under. checked for play anywhere i could, cf shafts don't have any play. when wobbling the cv shaft vertically (like bench pressing it) i saw that the axle stub going into the diff was moving. then started inspecting the diff more. god dammit the pinion isn't contacting the ring gear at the right pattern. i ignored the diff the whole time cuz it was professionally done and costed an assload and we used all new bearings everywhere.

i'm gonna call the shop and tell them it def needs to be adjusted/shimmed/etc. hopefully they agree.

anyone have any advice if they act like dooshbags?

[clark]

bumping this for more advice.

took the car to the shop. a few guys looked at it on a lift, we all agreed that maybe the pinion wasn't making proper contact with the ring gear so they said they'd use a thicker crush collar on the pinion.

well the pulled the diff down today, didn't disassemble it, but only took the cover off, NO PLAY. tested by hand and with a dial, there is NO PLAY. i'm pissed, well sort of. this means that there still is a slight chance it's still the diff and only happens if the diff is under a slight load, or maybe the spider gears inside of the helical are messed up, but i doubt it.

anyone have any ideas??? this is driving me nuts!