98 V70R AWD CEL codes and CV axle

[dcmike]

I acquired a 98 V70R AWD at the beginning of the summer. The car needed some work but was drive able. Over the last week I replaces the nivomat rear shocks with some used ones and that went well. The next problem was the rear O2 sensor needed to be replaced , I kept getting CEL P0136. To make a long story shorter, I ended up dropping the S pipe out of the car to get both sensors out. I had to remove the yoke off the transfer case to get the S pipe out. I replaced both sensors with new ones. Then put the driveshaft and yoke back in.

During this time I also replaced the right front CV axle, the axle was shot and making the thumping noise when turning. I test drove the car and the car now has a horrible whine from the right front. The same side that I replaced the CV axle. The CEL of P0136 came back. Also when the car is under hard acceleration it misfires on the number 4 cylinder.

Could the axle be junk out of the box? The axle is from CarQuest. Does the yoke have to be shimmed when put back onto the transfer case shaft. Is this what the whinning is? Both of the O2 sensor are Bosch and for the car. I also do not understand the misfiring.

Thank you.

[scot850]

The AWD V/S 70's are a challenge a lot of the time, particularly as they get older and many parts are now becoming obsolete.

However, in the case of your car, assuming you fitted the correct axle for the year and AWD could well be bad. I prefer to use a good used Volvo one over most after market because of the issues with aftermarket and re-built units I have had.

There is a carrier bearing on the RH axle that may be bad if the unit has been re-built. I recently pulled 2 RH axles and both had good CV joints but both had bad carrier bearings. Did you check the hub bearing while in bits? It needs to be nice and smooth with not roughness. The axle bearing my show up worse if you load the axle up when turning left.

What brand of O2 sensors did you use? These cars are particular in what they work with, there are also a lot of phony parts out there on E-bay and Amazon claiming to be Bosch (which are the only brand I recommend).

The prop-shaft joint behind the angle gear (transfer case) is problematic as they stuck it right beside the cat so it tends to fail and in turn it causes vibration and can cause the rear bearing in the angle gear to fail. Check it for movement. Also check the center carrier bearing as they can also get noisy and the rubber support ring rots out making it knock. While in there check the front bush on the viscous coupling housing (the unit attached to the rear of the prop-shaft) as they wear out and can cause a knock as well.

The angle gear is a weak spot and it has an internal sleeve that connects the transmission to the angle gear which can strip it's teeth and make noise in doing so, and if the oil has not been changed or topped up (check for recommendations on oil, here I only use Volvo option but I know others have suggested alternated but don't know what they are).

This is a start, but covers most of the normal issues with these cars.

Neil.

[dcmike]

The O2 sensors, one was from NAPA and the other was from FCP. I did notice when driving the car in circles that the noise was worse, more one way than the other. The noise was coming more from the right front, then the center of the car. I did not really check the hub that well. I was in a hurry to get done. The CV axle was not a brand name and Im leaning to a poor quality. I may order one from IPD.
The part that sucks is when the nut comes off the axle it usually takes the treads with it. So you can not reuse the axle.
I did top off the transfer case oil and some of the noise went away.
I will work on the car tomorrow and see what shakes out.

[scot850]

I have not damaged the threads removing the axle nut itself, but have really damaged them trying to remove them from the bearing splines. Volvo used a 'glue' to stop movement of the splines when they first installed the axles when new and were supposed to do so when replacing but often the didn't. Most on here will recommend that rather than do that, use anti-seize on the splines when fitting to make it easier to remove if you have to do it again in the future.

Rather than buy a new axle, try Erie Vo-Vo in New York area to see if they have a good used Volvo one. If they have one they guarantee them for life. In my opinion, better than a cheap aftermarket unit or badly re-built one. I think I paid $125 or so for the one I got from them recently.

To remove the axle nut I use an electric impact gun, similar to the one I believe guys have mentioned you can get from Harbor Freight in the US. Mine supposedly gives up to 350 ft/lb of torque and as yet has never let me down undoing these nuts.

When removing the last frozen axle from the bearing I had to use a large 3 legged puller to push the axle out. The fact you have removed it recently it should hopefully come back out easily. When you have removed it check the carrier bearing for any noise. It should be quiet and make sure it is a sealed bearing. The AWD has a longer machined area on the inner end to clear through the angle gear to get to the transmission compared to a FWD version.

I think the last time I got not stupidly priced O2 Bosch sensors it was from Rock Auto of all places. Be careful that you order the correct one as there are a few used over the years, but maybe only 2 or 3 for front and back.

Again, the front wheel/hub bearing should be smooth to turn. I think the last one I used was from WorldPac and was a Febi branded one. Used it on a 97 850 non-turbo.

Neil.

[erikv11]

Great details from Neil na what to look for.

to OP - I agree strongly that the used axle is a much better way to go.

[dcmike]

Went out this morning and pulled the axle back out. I sprayed the threads with croil and has no issues with the treads. The hub turns smoothly and has no discernible play. When I first picked up the axle, the parts store gave me a axle for a FWD not a AWD. Their was a big difference with the shaft diameter at the bevel gear case end. So I had to re order the axle from the parts store. Before I installed the axle, I compared the Volvo axle to the FEQ, First Equipment Quality. They axles where the same length. So I'm not sure of the difference.

I had to remove the companion flange from the gear case to remove the s pipe. Could the whining noise be from the bevel gears being out of shim from the removal and then install of the flange? I looked around for torque and end play for the flange but did not find anything. I ran the nut back on with a impact gun then a little more with a breaker bar.

With the O2 sensors, I disconnected the battery and letting it set while I deal with the rest of the problems. I did buy the correct sensors. Well I hope I did. I have had very good luck with NAPA and FCP. The OEM connectors on the sensors did match up to the wiring harness on the car. I will let you know what happens next. I may check the plugs and see what is going on there also.

[scot850]

The only differences SHOULD be the quality of the manufacture of the parts and tolerances. However, the reality is often the quality of the materials is not as good, and things like shaft balance and bearing fitment can make them poor to drive on. I had a 93 850 which was fitted with and aftermarket axle that was so bad, that I thought the transmission was failing. It vibrated badly at certain revs and make it feel like the trans was slipping. Withing 2 years the CV boot failed, and I knew more about the poor quality of most aftermarket new or re-manufactured units, I bought an axle from a Volvo used parts specialist and once fitted the car was transformed and ran really smoothly and no transmission slipping feeling any longer.

As to the rear angle gear flange there is a torque value of course, but I will have to see if I can find what it is. Over tightening can damage the unit, but not sure that is the issue here. There is no easy way to check it without dismantling the angle gear. What you can do is remove the prop-shaft and making the car FWD only and see if the issue/noises reduce or goes away.

On the O2 sensors, if they are Bosch they should be OK from those 2 sources I would suggest. If either is not Bosch then you are in the lap of the gods on if they work with the cars or not.

Neil.