Transmission swap

(Lindsay) #1

Is the series 3 gearbox (BW 66) a straight swap into a series 2 (BW 12)

(Robin O'Connor) #2

A quick search using the spy glass (top right) returned a few old posts regarding this, seems like its a goer.

(Geoff Allam) #3

Are you sure your series 2 had a bw12? My series 2 1976 had a bw 65 which is a direct swap for a 66

(Lindsay) #4

no not sure but as it is a 74 I just assumed how do you tell

(Frank Andersen) #5

The box itself is, Lindsay…

However, connections between the gas pedal and the box is very different. You need those parts from the S3 version…

xj6 85 Sov Europe (UK/NZ)

(Robert Laughton) #6

Pull the dipstick. It will be stamped 65 or 66 on its end.


(Jochen Glöckner) #7


why do you assume?

The Parts catalogue makes mention of BW35 for 2.8 l and BW65 for 4.2 l from 7L.83800. Until then BW12. A PO may have changed things though as BW65/66 are fairly plentiful.

Good luck


75 XJ6L 4.2 auto (UK spec)

(Lindsay) #8

thanks for that but unfortunately no stamp but I do believe the bw12 are a cast steel body and the 65/66 are alloy so next time im under car will check

(David Jauch) #9

65/66 have a kickdown cable at the throttle body. The 12 has vacuum or electric or both. That should be enough to rule out PO changes.

(Lindsay) #10

it is a 12 in my car as its steel cased and the number on the tag ends 12J so does the 66 go straight in or are there modifications required ie rear mount or driveshaft

(David Jauch) #11

Mount needs to be the 12‘s but it bolts right up. Some have done it, if you use the search function there are descriptions on what to do.