One question that comes into the workshop on a regular basis is;
What gearbox is in my Defender?
The main gearboxes we get asked to identify are the R380, LT77 and LT85. There are many others and we will look at some of the detail below.
Below is a handy reference table to help you identify the main features of each box from their serial number.
Types of Gearbox
|Serial No Style
|4 Speed box with integral transfer box found in early Series III 109 V8, 110 V8, 101 FC and Range Rover
|5 Speed box fitted from 1983 to approx 1994
|17A-74A PrefixA-H Suffix
|5 Speed “Santana” box fitted from approx 1988 to 1991
|20C & 22C Prefix
|5 Speed box, replaced the LT77 fitted from approx 1994 to 2006
|17A-74A PrefixJ on Suffix
|6 Speed Ford Getrag box introduced with Defender 2007 MY
|4 Speed used in Freelander & some Rover Car models
The first thing you need to do is note down your gearbox serial number.
The Gearbox Serial Number Stamped on a machined flat near the Drain Plug area.
The Number Consists Of :
- A Prefix e.g. 56A
- A six digit numerical
- A Suffix Letter. Suffix A to H is an LT77 Transmission, Suffix J onwards is an R380 Transmission.
The first 2 give the application, ie 50A is 4 cylinder petrol and 4 cylinder diesel N/A and TD. These start from 1983 with the suffix ‘D’ 77 to the ‘H’ 77 and go up to the suffix ‘L’ for the R 380. They vary hugely but all have the prefix 50A.
Once you have the serial number you need to pay attention to the first 2 digits of the serial number but the last is very important also.
- The 51A is the military 77, lower 1st and 2nd, run from D to H suffixes,
- The 200 TDi used the 56A, all were suffix G or H, replaced by the 44A R 380, J to L
- The 300 defender used the 56A R 380, most were J but go up to L
- The 300 military was the 58A, same as above but with an oil cooler casting on the side
- The TD5 was the 68A suffix L, Europe spec (non oil cooled)
- The 74A was the TD5 def ROW (oil cooled) spec
- The 66A was for the MPI defender (Italian police)
- The 60A was the non oil cooled V8 def, 77 and 380, G to L
- The 61A was the oil cooled def 77 and 380 G to L
Reverse Gear Position
The reverse gear can be used to give you basic information on whether you have an LT77 Gearbox or an R380 Gearbox.
- If Reverse is next to 1st gear. You have an LT 77 or 85 gearbox
- If Reverse is below 5th and inline with 4th gear you have an R380 transmission.
Once you have identified your gearbox you can safely order parts.