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The output shaft seal sits where the transfer case's rear output shaft exits the housing to drive the rear driveshaft (or front, on some AWD layouts). It is a small rubber-and-metal seal, but it takes constant rotation and road grime, and it is one of the most common sources of a slow drip under the transfer case that owners mistake for a transmission or rear differential leak.
Before you replace the seal, confirm the leak is actually coming from there and not from the adjacent extension housing seal or a transmission output seal one bolt forward — all three pool fluid in roughly the same spot on the ground.
What Drives the Cost
Seal Only, No Other Damage
If the shaft and bearing surface are in good shape and the seal simply hardened or wore out, this is a straightforward swap: pull the driveshaft, remove the old seal, press in the new one, reinstall. Parts cost is low; the job is mostly labor to access the seal.
Typical cost: $15-40 for the seal itself, plus 1-2 hours of labor if a shop does it.
Seal Plus Output Shaft Bearing
If the leak has been present long enough, or the bearing itself is worn, the seal rides against a damaged or pitted bearing surface and will not hold even when new. In that case the bearing needs to come out with the seal, which is why many shops recommend doing both together rather than chasing the same leak twice.
Typical cost: $130-210 for a combined bearing and seal kit, depending on the case. This is the same labor window as the seal-only job since the case has to come apart either way.
Full Reseal Kit
Some transfer cases are better served by a full reseal kit that covers every gasket and seal in the case at once, not just the output shaft. If the case is already open for one leak, replacing every seal at once avoids a second teardown when the next one starts dripping six months later.
Typical cost: $170-210 for the kit, same labor as above.
Decision Table
| Situation | Fix | Approx. Cost |
|---|---|---|
| Fresh leak, shaft/bearing surface clean | Seal Only | $15-40 |
| Leak has been present a while, or bearing is worn | Bearing & Seal Kit | $130-210 |
| Case already open, want to avoid a repeat job | Full Reseal Kit | $170-210 |
A seal that keeps leaking again within a few months after a seal-only fix is almost always a sign the bearing surface was already damaged when the seal went in — that is the case for stepping up to the full kit the second time around.
Output Shaft Seals and Bearing Kits Ship Same-Day
We stock seals, bearings, and reseal kits for the most common transfer cases on the road. CoreTransmissionParts carries the broader catalog if you need something we don't stock direct.
Shop Gearbox Insider → Shop CoreTransmissionParts →FAQ
How do I know the leak is the output shaft seal and not the transmission?
Wipe the area dry, then check it again after a short drive. The transfer case output seal leaks right at the rear of the transfer case housing where the driveshaft slides in, while a transmission leak typically shows up further forward, at the transmission's own tailshaft or pan. If both are wet, trace the fluid path back from the lowest drip point.
Can I replace the seal without dropping the transfer case?
On most trucks, yes — you only need to drop the rear driveshaft and support the transfer case, not remove it entirely. Some front-output seals on AWD cars require more disassembly to access.
Is it worth doing the full reseal kit instead of just the one seal?
If the case is already open for this repair, yes — the incremental parts cost is small compared to paying labor to get back in there for the next seal six months later.