240D differential swap
This has been covered frequently even by me. I now have my final definitive report. My 240 D has 195x70x14 michelins and a MT. With the stock 3.69 dif it performed about as expected with a nice granny first gear and balanced shifting. It 65 the engine was turning pretty high, at 75 ridiculously high esp compared to my 85 300D with an AT.. I found a low mile 3.07 following the advice given by a fine well known mechanic in Bellingham WA. Pros: extremely quiet low revs at highway speeds but getting there took a while. Better economy 37+ with my new injectors compared to 35-36. Cons: needed a lot more clutch esp staring on soft ground. Frequent stalls. Lost speed going up even slight grades. Much diminished acceleration. I had some 185x60x14 tires from my old corolla and decided to put them on the back. This had the effect or changing the effective FD Dif from 3.07 to about 3.44. Pros: much improved standing starts with minimal clutch needed. Better acceleration . Cons: the diameter is about 2" less compared to 195 tires so the car sits a little lower, an inch or so but I cannot go back to the 3.07 ratio. Conclusion the 3.4+ is the ideal ratio for the 240D. I am pondering putting in a 3.46 which would allow me to have taller tires. I wonder if putting in a 3.46 ring gear would be easier. Swapping out these difs is a simple job and worth doing esp if you have boots or dif seals, flex couplings to do(I don't). Should I just be happy with the little tires?
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