XF EDDIE 247 Posted January 7, 2025 I'm not sure if this is ok on this forum because its for an AU so let me know if I'm in the wrong place. Recently a mate killed the BTR 4 speed in his series 3 AU and he wants to pay me $500 to do the job. Now I am wondering what was different between the btr's between the models. I found a box out of a BF that is supposedly in good condition but I'm not sure what if anything needs to be changed to fit it to a AU. So what boxes are compatible and what do I need to keep from the old box? Also is it worth it to rebuild these gearboxes or am I better off just getting a new one? Share this post Link to post Share on other sites
Thom 6,716 Posted January 7, 2025 Ea to au btr's are mostly interchangeable, in 6 cylinder cars with another 6 cylinder btr (some v8's had sports shift like ed sprint, el gt, au ts50 etc) to use an earlier btr in an au it is recommended to fit the au bellhousing to the e series transmission (straight swap make sure you get the converter re seated correctly), the e series bellhousing wilbolt to the au engine but it won't bolt to the sump, you'll need to use the au speed sensor, neutral safety switch and wiring, ba an later btr's can't be used in a ea-au (except maybe column shift ute transmissions but im not certain on that one) as they don't physically have shift positions for 1st to 3rd and are setup to run with the "sports shift" shifter, also unless it is a ute transmission it won't have a mount for the speed sensor (without it the transmission won't shift) as ba to fgx (except ba utes) all came standard with abs and use the abs sensors to tell the ecu how fast the car is going for controlling shift points 1 1 XF EDDIE and deankxf reacted to this Share this post Link to post Share on other sites
XF EDDIE 247 Posted January 7, 2025 Ok so b series transmissions are a no go? Ill see if I can get one from an au, any difference between year models? 1 deankxf reacted to this Share this post Link to post Share on other sites
Thom 6,716 Posted January 8, 2025 Ok so b series transmissions are a no go? Ill see if I can get one from an au, any difference between year models?All au trans will be a straight bolt in, just make sure you use the electronics from the car as one of the years has a different gear position indicator and I can't remember which one Share this post Link to post Share on other sites
deankxf 21,470 Posted January 8, 2025 8 minutes ago, Thom said: All au trans will be a straight bolt in, just make sure you use the electronics from the car as one of the years has a different gear position indicator and I can't remember which one what electronics do you mean for this Thom? Share this post Link to post Share on other sites
Thom 6,716 Posted January 8, 2025 what electronics do you mean for this Thom? Speedo sensor, gearshift indicator (sometimes referred to as neutral safety switch) and wiring loom, only external, internal wiring doesn't need to be changed 1 deankxf reacted to this Share this post Link to post Share on other sites
deankxf 21,470 Posted January 8, 2025 3 minutes ago, Thom said: Speedo sensor, gearshift indicator (sometimes referred to as neutral safety switch) and wiring loom, only external, internal wiring doesn't need to be changed interesting, A mate of mine's Dad's AU ute has an EL trans, and he's about to fit an AU trans in an XG (using XH transmission loom) wonder what's actually different. i'll reply here if he finds any issues with this combo. (assume the AU with EL trans used all the AU stuff though) Share this post Link to post Share on other sites
SPArKy_Dave 9,416 Posted January 8, 2025 I'd imagine many earlier BTR's would be fairly worn out by now, either clutches, or even just the second/fourth band? Not to mention potential gummed up solenoids, or valvebody? Share this post Link to post Share on other sites
gregaust 334 Posted January 8, 2025 Just to clarify a bit , up to AU internal wiring is grounded inside the transmission . From BA on , the internal harness is different and the grounds to all solenoids go back to the ECU , so they are a no go. There is also a variation in AU I came across . Although the internal harness looked the same the plastic plug into the case was a different size/diameter than the earlier models . Not really an issue . I only came across it as a mate built one , wanted to use the late case , then found his earlier case from a V8 EB or ED or whatever it was different where the harness fitted . Luckily I had an AU harness worked 3 Thom, SPArKy_Dave and deankxf reacted to this Share this post Link to post Share on other sites
XF EDDIE 247 Posted January 8, 2025 Hey thanks for your help everyone, turns out that for some reason he decided to sell the car which he paid $3500 for $100 to a guy who is making it a paddock basher even though he was previously offered over a grand for it. He decided to tell me this afternoon even though he did it a week ago. So theres some time Ill never get back chasing parts. On the flip side this thread has given me some useful info about btr boxes. 1 1 deankxf and gregaust reacted to this Share this post Link to post Share on other sites