Discussion
I have been trying to track down the source of a noise and my investigations led me to the diff output bearings.
"A whirring noise that starts at about 20mph and whirs according to road speed.
Knocking it out of gear so the engine is idle doesn't change the noise (except it gets slower again).
The whirring noise disappeared when cornering left"
I have now removed the diff on its cradle stripped off the calipers and removed the output bearings, and they don't particularly feel grindy or flapping around loose, although one feels tighter to turn than the other. Should they turn effortlessly and silently or is some whispering OK? While I have the diff out I suppose there's nothing to lose by changing the bearings, will they need pressing in/out etc?
The front bearing shows a bit or end float, and if I press on it while turning I get a noise from the diff internals, so I wonder if that's the problem, well it seems to be a problem anyway. As I recall the front bearing is the technically more difficult one to replace? It also leaks so the seal needs doing.
The crown wheel teeth look in good nick except for a small chip on the very corner of one, but it seems far away from where the pinion should engage so probably not an issue.
"A whirring noise that starts at about 20mph and whirs according to road speed.
Knocking it out of gear so the engine is idle doesn't change the noise (except it gets slower again).
The whirring noise disappeared when cornering left"
I have now removed the diff on its cradle stripped off the calipers and removed the output bearings, and they don't particularly feel grindy or flapping around loose, although one feels tighter to turn than the other. Should they turn effortlessly and silently or is some whispering OK? While I have the diff out I suppose there's nothing to lose by changing the bearings, will they need pressing in/out etc?
The front bearing shows a bit or end float, and if I press on it while turning I get a noise from the diff internals, so I wonder if that's the problem, well it seems to be a problem anyway. As I recall the front bearing is the technically more difficult one to replace? It also leaks so the seal needs doing.
The crown wheel teeth look in good nick except for a small chip on the very corner of one, but it seems far away from where the pinion should engage so probably not an issue.
All wheel bearings are fine, as are the two output shaft bearings on the diff.
I think I worked out the turning left thing was the propshaft leaning to the right, which altered the angle (slightly) and tightness of the pinion bearing, and hence the contact of pinion to crown wheel.
Still, we shall see after it's fixed up and refitted.
My next job is to remove the bearing from the pinion shaft which is proving f****** tight. Tried heat last night, might try freezing + heat next.
I think I worked out the turning left thing was the propshaft leaning to the right, which altered the angle (slightly) and tightness of the pinion bearing, and hence the contact of pinion to crown wheel.
Still, we shall see after it's fixed up and refitted.
My next job is to remove the bearing from the pinion shaft which is proving f****** tight. Tried heat last night, might try freezing + heat next.
What car and age is t? That might help. How have u checked the wheel bearings the ensure they are fine? Spinning them up and listening for roughness will only show up particularly bad bearings. If you spin it up with the wheels on and hold the suspension arm or an upright then you can feel more subtle roughness by the vibrations on the suspension arm but even this isn’t full proof.
It almost sounds like your justifying it to be the diff but I still think it’s unlikely to make much difference loading and unloading if it’s the diff
It almost sounds like your justifying it to be the diff but I still think it’s unlikely to make much difference loading and unloading if it’s the diff
Hi Billy,
it's a 1989 TVR 400SX (wedge shape), 85k miles.
I've had wedges for 25 years, largely maintaining them myself, and have had experience of wheel bearings going over the years. SO this time, I don;t think it's them. I actually did both front bearings to try and get rid of the noise anyway,.,, no problems there.
The rears on the wedge do really go when they go so it's pretty obvious.
Besides the diff is dropped off the car now, and I have an obvious fault to rectify with the pinion bearing. My main question at the moment is whether to do the output shaft bearings, or leave them alone.
it's a 1989 TVR 400SX (wedge shape), 85k miles.
I've had wedges for 25 years, largely maintaining them myself, and have had experience of wheel bearings going over the years. SO this time, I don;t think it's them. I actually did both front bearings to try and get rid of the noise anyway,.,, no problems there.
The rears on the wedge do really go when they go so it's pretty obvious.
Besides the diff is dropped off the car now, and I have an obvious fault to rectify with the pinion bearing. My main question at the moment is whether to do the output shaft bearings, or leave them alone.
Thanks for the advice. I have used similar techniques for wheel bearing shells.
First wait till the missus isn't looking, turn the fridge down to -22C and leave it int here overnight.
What will the replacement shell take? I was thinking 100C (boiling water) might be fine, but probably not much hotter?
First wait till the missus isn't looking, turn the fridge down to -22C and leave it int here overnight.
What will the replacement shell take? I was thinking 100C (boiling water) might be fine, but probably not much hotter?
Gassing Station | Engines & Drivetrain | Top of Page | What's New | My Stuff