Transfer Box V Gearbox splines

[Wolfywolf]

Hi all.

I have recently noted that there is a problem on my 2005 XC90 AWD (I got stuck on a piece of grass that was about a meter square) so I did the old spinny the prop shaft thing and it turned freely without noise, I have had the car for a year and don't know if the AWD ever worked.

I am presuming that either A: The bearings have gone inside the TB.. or B: The splines have turned to dust.

I have been told that once apart it will be near impossible to put it back together if the gearbox splines have gone (I will not be replacing the GB and the TB together because of the cost as the TB alone is costing £1500 to be done) if the GB splines are fluffed I am not replacing the TB and it can stay 2WD until the end of its life.

I have a pretty decent gearbox in the car and am hoping that the splines have not gone on it, I know this will be speculation but what are the chances of the gearbox output splines going versus the input splines on the transfer box being worn away?.

Cheers

Allan.

[owenfackrell]

My understanding is the the gearbox splines are normally ok and it is the splines on the sleeve that are the weak point and when these wear and are left undetected then they can wear the ones on the transfer box. The sleeve is only about £100 or so to buy but it is quite a bit of labour to change it.

The bearing went on our transfer box and when it went it caused the prop shaft to wobble. The prop shaft still gets turned by the rear wheels as the Hadlex unit functions properly and detects the difference in speed between the prop shaft and the rear diff. I had to disable the Hadlex unit on our car as the wobble prop shaft was causing the bits in side the transfer box to catch and lock up the rear wheels. This happened as we drove down through France, not a nice experience at 70-80mph.

[Wolfywolf]

Ouch, having the back lock up is not good at all, I was also under the impression that it was just the transfer box side that suffered, I'm hoping that is the case or I'm in a bit of a bind.

Cheers

Allan

[john langrick]

Hi, most common is the spline gear on earlier (pre 06) which have a weaker spline gear. I have my03.

Mine certainly wore on the transfer box end and had also partially worn the input socket in the transfer box. The gearbox end was fine.

I would guess that the longer the spline gear has failed and hence rotating in the transfer box, the more likely it is to damage the transfer box.

Replacement units are a stronger spline drive and less prone to failure I understand.

The new spline drive includes oil seals and retaining clip and best buy is the genuine Volvo.

I had a transfer box from a breakers standing by and I changed in any case.

Hope this gives some reassurance.

John l

[Wolfywolf]

Thank you John.

My 05 has 209,000 Miles on the clock, I have done 12,000 of them and I am not sure how long it has has been since it failed, Fingers crossed that the gearbox side is ok.

Cheers

Allan.