Jack Posted April 9, 2007 Share Posted April 9, 2007 I have a 1981 2 door RR with a 3 speed torqueflite and a LT230 with 1:1.003 final. Q: What problems will I cause in doing a swap from the 3 speed to a 4 speed ZF box? Is an overdrive a better way to go to reduce revs at highway speeds? Jack Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 9, 2007 Share Posted April 9, 2007 Dunno about prices where you are but an OD is almost certainly going to cost more than a 4-speed. I don't think the 4-speeds were any faster overall but they all ran behind a 1.222:1 transfer box so on yours it will end up faster in theory but may be over-geared. Look at Ashcrofts site for gear ratios. Quote Link to comment Share on other sites More sharing options...
Bille Posted April 9, 2007 Share Posted April 9, 2007 I have a 1981 2 door RR with a 3 speed torqueflite and a LT230 with 1:1.003 final.Q: What problems will I cause in doing a swap from the 3 speed to a 4 speed ZF box? Is an overdrive a better way to go to reduce revs at highway speeds? Jack Quote Link to comment Share on other sites More sharing options...
Bille Posted April 9, 2007 Share Posted April 9, 2007 I have an '80 2 door manual with OD and get about 2 litres per 100 klm better econnomy with it engaged, I also have a '93 with the ZF and was recently told by the local auto service shop that the Torqe Flight is almost indestructable compared to the ZF, so I guess it depends what use you have for the vehicle. I do know that when a mate had an '81 with the Torqe Flight but no OD it was very sluggish until the revs were up then it was OK. Hope this helps. Quote Link to comment Share on other sites More sharing options...
Jack Posted April 10, 2007 Author Share Posted April 10, 2007 I have an '80 2 door manual with OD and get about 2 litres per 100 klm better econnomy with it engaged, I also have a '93 with the ZF and was recently told by the local auto service shop that the Torqe Flight is almost indestructable compared to the ZF, so I guess it depends what use you have for the vehicle.I do know that when a mate had an '81 with the Torqe Flight but no OD it was very sluggish until the revs were up then it was OK. Hope this helps. Thanks. It seems that the 3 speed, although slow, can't be beraten for strength. Just have to put up with it since the cost of conversion is about double what I paid for the RR in the first place. Jack Sydney. Quote Link to comment Share on other sites More sharing options...
FridgeFreezer Posted April 10, 2007 Share Posted April 10, 2007 The TF is an american box, although LR replaced a lot of internals with weaker ones they are still strong (the racing boys love them) but for everything else a ZF is more than strong enough. Quote Link to comment Share on other sites More sharing options...
DEANO3528 Posted April 10, 2007 Share Posted April 10, 2007 To add to the above The ZF is far smoother and refined than the Torqueflite and the engine braking in low first gear is far superior in my experience. Quote Link to comment Share on other sites More sharing options...
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