how to topup gearbox fluid and where do i top it up ??

Automatic or manual?

manual

ARTICLE BEGINNING
IDENTIFICATION
MANUAL TRANSMISSION/TRANSAXLE APPLICATIONS
Model Transmission/Transaxle
Corolla 5-Speed - Model C50 Or C52
LUBRICATION
SERVICE INTERVALS
Check lubricant level every 15,000 miles or 24 months. Replace fluid at 15,000 mile intervals if
vehicle is operated in severe service conditions. Severe service conditions include trailer towing,
repeated short trips in cold weather and operation on dusty or salt spread roads.
CHECKING FLUID LEVEL
Transmission/Transaxle
Remove left engine undercover (if necessary). Check fluid level at fill plug hole. Lubricant should
be level with bottom of fill hole.
Transfer Case
Drain and fill plugs on 4WD transfer cases are separate from main transmission/transaxle case.
Lubricant should be level with bottom of fill hole.
RECOMMENDED FLUID
All transmission/transaxles except S54 use API GL-4 or GL-5, SAE 75W-90 or 80W-90 gear oil.
The S54 transmission uses Dexron-II ATF. The E153 uses E50 transaxle oil. The V160 uses
Toyota V160 Gear Oil.
FLUID CAPACITIES
TRANSMISSION/TRANSAXLE REFILL CAPACITIES
Application Qts. (L)
Corolla (SAE 75W-90) 2.7 (2.6)
ADJUSTMENTS
SERVICING - M/T -1993 Toyota Corolla Page 1 of 2
http://www.ondemand5.com/mric/common/asp/printart.aspx 11/23/2011
NOTE: Adjustments are not required during routine servicing and
maintenance.