Possible Causes:
* Low Transmission Fluid: Check the transmission fluid level *immediately*. A severely low level can cause the transmission to slip and eventually fail to engage gears. If low, add the correct type of automatic transmission fluid (ATF) specified for your Rover's transmission. However, *only* add enough to bring it to the proper level on the dipstick; overfilling is just as bad as underfilling. This is a relatively simple check but unlikely to solve the problem if it's already gone neutral.
* Transmission Linkage Problems: The linkage that connects the gear selector to the transmission could be broken, dislodged, or severely worn. This is less likely given it went fully neutral, but it's worth a quick visual inspection. Look for anything obviously disconnected or damaged around the shifter mechanism.
* Internal Transmission Problems: This is the most likely culprit. The failure could be due to:
* Broken or worn internal components: This could include things like clutches, bands, planetary gears, or valve bodies. These components wear over time and can fail suddenly.
* Low or contaminated transmission fluid: Even if the level isn't drastically low, contaminated fluid (e.g., burnt, dirty) can cause internal damage and prevent gear engagement.
* Solenoid or valve body failure: These electrical components control the flow of fluid within the transmission. A fault in these can prevent gear selection.
* Torque converter issues: The torque converter is the fluid coupling between the engine and transmission. A failure here could prevent power transfer.
* Electrical Problems: Though less common, a problem with the transmission's electrical system (e.g., a faulty shift solenoid, wiring harness damage) could be the cause.
What to Do:
1. Don't attempt to force it: Trying to force the transmission into gear could cause further damage.
2. Check the transmission fluid: This is the first and easiest thing to check. Note the color and smell of the fluid; dark brown or burnt-smelling fluid is a bad sign.
3. Visual inspection of linkage: Carefully examine the linkage connecting the shifter to the transmission.
4. Professional Diagnosis: This is absolutely crucial. You'll need a qualified mechanic specializing in older automatic transmissions (especially those from British cars, which can have unique quirks). They will need to diagnose the exact problem using specialized tools and likely will need to drop the transmission pan to inspect the fluid and internal components.
Costs: Expect significant repair costs. A simple fluid change is inexpensive; however, internal transmission repairs or a replacement could be very costly, potentially exceeding the value of the vehicle. A proper diagnosis is the first step to determining the extent of the damage and the associated repair costs.
In short, your Rover's transmission likely requires professional attention. Attempting DIY repairs without experience is strongly discouraged; you risk making the problem worse.
