STC4348 | Mainshaft 3rd/4th Gear Kit - R380 5-speed manual | Defender 1987-2006
To check the stock of Genuine Parts before placing an order please use our Contact Us page
To check the stock of Genuine Parts before placing an order please use our Contact Us page
To check the stock of Genuine Parts before placing an order please use our Contact Us page
Land Rover Part Number: STC4348 - Mainshaft 3rd/4th Gear Kit
STC4348 is a Mainshaft 3rd/4th Gear Kit for the R380 5-speed manual transmission. This kit contains the matched 3rd and 4th gears that fit onto the mainshaft and mesh with the layshaft and selector components to provide the third and fourth forward ratios; the gears are produced with the correct tooth profiles and hardened surfaces to carry load in both highway and off-road use.
Use the compatibility data below to confirm fitment against your V.I.N.
Fitted to Defender models with the R380 5-speed manual transmission, the kit is intended for repair or overhaul of the gearbox mainshaft assembly when third and fourth ratio components are worn or damaged. During reassembly, maintain correct endfloat and bearing preload for the mainshaft and follow gearbox assembly practices to preserve gear alignment and synchroniser operation. Use the compatibility data below to confirm this kit matches your vehicle specification before installation.
Compatibility
- Defender (1987-2006) - R380 5-speed manual transmission
Frequently Asked Questions
The STC4348 supplies the matched third and fourth mainshaft gears for the R380 5-speed gearbox, allowing the mainshaft to transmit torque through the third and fourth forward ratios by meshing with the layshaft and selector components. Common failure modes include worn or chipped teeth that produce noise, difficulty selecting gears or uneven wear; replacing the matched gears restores correct mesh geometry and backlash. During installation ensure correct mainshaft endfloat and bearing preload to preserve gear alignment and synchroniser operation.
| Model | Variant |
|---|---|
| Land Rover Defender (1987-2006) | Mainshaft Gears 3rd/4th (R380 5-speed manual transmission) |
If you are unsure of compatibility with your vehicle, you can also confirm by checking against your V.I.N. Simply reach out to us with your V.I.N and desired part number via our Contact page or use our Finding Part Numbers page.
Replace the STC4348 when third or fourth ratio gears are worn, chipped or damaged, or as part of a gearbox overhaul. If there is noise, difficulty selecting gears or uneven wear, inspect the transmission and consult the vehicle service manual or a qualified gearbox technician.
- C8 products are usually supplied by Britpart.
- L8 products are genuine Land Rover parts.
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