Replacing pinion seals in 79 FJ40. Inspected bearings and races and look good. Shim style without crush sleeve. My question is can I set pinion preload with axles in or must they be out? Also what would be appropriate preload with old bearings and races? I have already replaced seals and have rotational torque wrench to set preload. Thank you in advance for any assistance.
pinion preload
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thanks. Do the axles have to be removed?
"Usually" pinion preload is set with just the pinion shaft and bearings without the seal. No ring gear or axles. Unless there is a spec given to do so.
Our shop typically set to the lower side of the spec tolerance for used bearings and the high side on new. But, you may get differing opinions on that.
Our shop typically set to the lower side of the spec tolerance for used bearings and the high side on new. But, you may get differing opinions on that.
Malleus
Far west of Siegen
Pinion nut preload can't be set with the downstream components (ring gear to wheels) connected, because you're measuring the (static, or breakaway) rotational friction of the pinion bearing stack. If you have the pinion gear in contact with the ring, etc., you won't get the same static resistance as specified in the FSM.
The FSM has two different preloads for new and used bearings:
New: 16.5-22.6 in–lb (19-26 kg–cm)
Used: 7.8-11.3 in–lb (9-13 kg–cm)
—the SAE units are mathematical conversions; there's no need to worry about the decimal points. Round up/down to the the nearest integer.
FWIW, the target was the middle when the assembly line set up the axles.
The overall preload, prior to backlash adjustment is 3.5-5.2 in–lb PLUS drive pinion preload. These specs are in the FSM. The procedure and values are the same for front and rear differential assemblies.
The FSM has two different preloads for new and used bearings:
New: 16.5-22.6 in–lb (19-26 kg–cm)
Used: 7.8-11.3 in–lb (9-13 kg–cm)
—the SAE units are mathematical conversions; there's no need to worry about the decimal points. Round up/down to the the nearest integer.
FWIW, the target was the middle when the assembly line set up the axles.
The overall preload, prior to backlash adjustment is 3.5-5.2 in–lb PLUS drive pinion preload. These specs are in the FSM. The procedure and values are the same for front and rear differential assemblies.
Axles out. Carrier out.
At that point, pull the pinion out and put new bearings in. Its a suck job, just do it once and be done with it.
Malleus
Far west of Siegen
Yes, once the nut is removed the preload is lost. This is why differential shops charge so much. There are no shortcuts.
Malleus
Far west of Siegen
FWIW, I used to build axles for a living. I wouldn't break down a differential just to replace a seal, unless someone paid me to do it. I'd do whatever it took to seal the pinion, until I had to break down the differential, and then I'd replace it properly.
...but then again, I've been ignoring an oil pan leak for a decade, so that's pretty much just me.
...but then again, I've been ignoring an oil pan leak for a decade, so that's pretty much just me.
