What This Cover Does
The base cover is the shroud that wraps the mounting area where the RH door mirror arm meets the body. It isn't structural. Its job is to keep road spray, salt, grit and UV off the mount and the wiring pass-through, and to give the corner of the cab a finished edge instead of exposed hardware.
Once the cover is gone or split, water sits in the mount pocket. That's where rust starts on the fasteners and where dirt packs into the seam. On heated and power mirrors, the harness feeds through that area, so a missing cover means the loom takes weather directly. Small part, but it protects a mount that's a pain to replace.
This one is the right-hand side, listed for 2017 through 2025 International LT 625. Left and right covers are not interchangeable, so confirm which side you're holding before ordering. Look at the truck, not the invoice from last time.
Why These Numbers Match
3766431C96 is the headline number most shops search. F01636-RS32 is the World Truck Parts number covering the same RH base cover for the LT 625. Both numbers describe one physical part: same side, same base housing profile, same mounting geometry on the door mirror assembly.
Cross-references exist because the same molded cover moves through more than one catalog. The supplier number and the number stamped in the parts system point at the same tooling. Listing F01636-RS32 here is for identification only. It does not mean PartStop is affiliated with, endorsed by, or authorized by any original equipment manufacturer.
Treat the cross-reference as a starting point, not a fitment promise. Verify by VIN, or better, pull the old cover and read the number cast or printed on the back of it. If the old part is smashed beyond reading, compare the mounting tab layout and the arm cutout against photos before you commit.
Inspect Before You Order
Check the mount itself while the cover is off. If the arm has been hit hard enough to tear the cover, the mounting bracket and fasteners often took load too. A new cover over a bent base will sit proud, gap at the door, and vibrate loose again. Fix the mount first.
Also check the retention points on the mirror base. Covers usually clip and screw. Broken clip bosses on the base mean the replacement cover has nothing to grab. Installation on a sound base is straightforward and needs no special tools, but a chewed-up mount changes that.
3766431C96 Cross-Reference & Interchange Numbers
These manufacturer and aftermarket numbers commonly cross-reference to 3766431C96. Use them to identify the part — then confirm the exact fit by VIN or the number stamped on your old unit before you order. An interchange is a starting point, not a fitment guarantee.
| Brand / Line | Cross-Reference Numbers |
|---|---|
| World Truck | F01636-RS32 |
Frequently asked questions
Is 3766431C96 the driver side or passenger side cover?
Passenger side, right-hand. The left-hand cover is a separate part and will not fit the RH mirror base. Stand at the front of the truck facing the cab if you're unsure which side you're looking at, then confirm against the old cover before ordering.
Does F01636-RS32 replace 3766431C96 exactly?
They cross to the same RH door mirror base cover for the LT 625. The interchange is listed for identification only. Confirm fit by VIN or by reading the number off the part you're removing, since trim and mirror configurations can vary across build dates.
Will this work with power and heated mirrors?
The cover shrouds the base housing and does not interfere with mirror function, so manual or power operation is unaffected. Route and seat the harness through the pass-through before seating the cover so nothing gets pinched. Verify the base configuration on your truck matches before ordering.
Not sure it fits? We check before you pay.
Run your VIN and we’ll match parts to your exact truck, or call the counter — a person who knows trucks verifies fitment by OEM number before the order ships. No wrong-box returns.
More cross-reference guides
Need the part, not just the reading?
Every part below is a Premium Quality aftermarket Direct Replacement with published OEM cross-reference numbers, a 6+ month warranty and same-business-day shipping from Tacoma, WA. Not sure it fits? Run your VIN — or call and a person who knows trucks will verify fitment before you pay.