1998 V70XC loud clunk from the rear end drivetrain

chaseinger · Post by **chaseinger** » Wed Nov 18, 2015 10:41 am

hello hive mind, i have a tad of an issue, hope you guys can help.

my xc is producing a loud noise, like a clunk, from the rear end when accelerating, especially around tight turns. looking at it it seems like there's no inspection plate or anythig for the rear split axle (thanks volvo, i guess they thought it'll never break), which i'm ssuming is the culprit.

i've exchanged the CV axles all around since they were pretty shot, which made the ride much smoother but didn't do away with the clunk. looks like i removed the symptoms but not the cause.

i know i can just drop the drive shaft and be done with it (i will, in fact, do this very thing this afternoon so i have a driveable car), however i did buy an AWD for a reason. i also exchanged the rear CVs for a reason.

so, there's 3 questions:

- try as i might i can't find a service manual for this car. i did find explosion diagrams which are very helpful, but any pointers, especially towards the rear end would be greatly appreciated.

- what is clunking? my guess is it's in the gearing inside the split axle, but that is what it is, just a semi-educated guess.

- is there a trick on how to remove the split axle without taking apart what seems like the entire rear end?

looking forward to your input! i'll follow up with pictures after today's operation so you chaps know what i'm talking about.

cheers!

jcdillin · Post by **jcdillin** » Wed Nov 18, 2015 11:04 am

Getting a copy of vida is really the best source of diagrams and repair procedures for this car, you can pick up a copy on ebay, I believe there also some download links in the vida forum section of this site.

Clunking could be the torque tube mount pictured here or it also could be your carrier bearing tearing loose.

Mine was doing the thump/clunk and it was the carrier bearing rubber mount torn loose. Worth checking the torque tube mount before pulling the propshaft.

jcdillin · Post by **jcdillin** » Wed Nov 18, 2015 11:34 am

Here are some diagrams, looking up the removal procedure as well.

: Prop.png (47.61 KiB) Viewed 1878 times

: Diff.png (114.27 KiB) Viewed 1878 times

: Diff2.png (121.16 KiB) Viewed 1878 times

chaseinger · Post by **chaseinger** » Wed Nov 18, 2015 1:15 pm

thank you kind sir, those are indeed the explosions i found as well. just downloaded a copy of VIDA, now all i need is a windows machine.

also a great pointer towards the torque tube mount. i'll have a close look at that.

keep 'em coming gents, hugely appreciated!

Post by **Big Will** » Thu Nov 19, 2015 2:13 am

Sounds to me like the freewheel of the viscous coupling if it's happening on corners at speed. Obviously check the mount on the torque tube and the driveshaft as suggested but it may be a sign that you need a new viscous coupling. Does this also happen as you are coming to a stop just before actually stopping?

chaseinger · Post by **chaseinger** » Thu Nov 19, 2015 9:51 pm

jcdillin wrote:Clunking could be the torque tube mount pictured here or it also could be your carrier bearing tearing loose.
Mine was doing the thump/clunk and it was the carrier bearing rubber mount torn loose. Worth checking the torque tube mount before pulling the propshaft.

you, sir, are a star. i inspected the drive shaft and torque tube today, and sure enough: the bushing of the tube mount hangs in pieces. my guess is it moves when torque is applied, thus misaligning inside the split axle and producing the clunk.

30 bucks replacemement on fcp euro parts ordered today, getting it on tuesday, the thanksgiving drive is saved! thanks a ton, i'll update after the exchange.

chaseinger · Post by **chaseinger** » Thu Nov 19, 2015 9:54 pm

Big Will wrote:Sounds to me like the freewheel of the viscous coupling if it's happening on corners at speed. Obviously check the mount on the torque tube and the driveshaft as suggested but it may be a sign that you need a new viscous coupling. Does this also happen as you are coming to a stop just before actually stopping?

that is a fear i had, and i have high hopes it actually is the tube mount. it's shot. happens not at speed, but mostly when accelerating from a stop into a turn. yes, also when shifting, but a lot less, and only lately. i do hope the worn mount didn't cause more damage.

chaseinger · Post by **chaseinger** » Wed Jan 04, 2017 11:14 am

sorry folks, i never updated this. i ended up removing the drive shaft. it's a FWD now.

whatever i'd tried, the clunking never went away, so short of opening the rear gearbox i decided to cut off the hind wheels from the drive train. dropping that main shaft was so much easier than anything i had tried to do before, and it feels as if i'm getting better mileage too.