ws721 Posted April 2, 2014 Share Posted April 2, 2014 Ok, I have 5.73's on 22.5 rubber with a .62 overdrive 6 speed which gets me @ 71 mph at 2100. My question is, if I put a set of 3.87 ratio rears in {because I have a spare set} what will be my 1st and Reverse ratio's? Will it be too fast in the yard? I don't haul heavy but don't a useless truck in the yard. Quote Remember if it's got a hood it's no good! Link to comment https://www.bigmacktrucks.com/topic/35281-tranny-ratio-low-speed/ Share on other sites More sharing options...
j hancock Posted April 3, 2014 Share Posted April 3, 2014 Is this a TRDXL 10780?If so, first gear will go from a 49.22 (with 5.73) to 33.24 (with 3.87).Rev is 50.48 (with 5.73) to 34.09 (with 3.87).It still should be pretty decent in the yard.On the other side, which engine do you have and will it like trying to pull a load with a 2.39 ratio when it is in sixthgear? 3.87 X .62 = 2.39Sixth gear @ 2100 rpm will now give you 105 mph. 1 Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/35281-tranny-ratio-low-speed/#findComment-240454 Share on other sites More sharing options...
ws721 Posted April 3, 2014 Author Share Posted April 3, 2014 Its a TRXL 1070. I was just wondering. I wouldn't put that high a ratio rear in it with a 6 speed. Quote Remember if it's got a hood it's no good! Link to comment https://www.bigmacktrucks.com/topic/35281-tranny-ratio-low-speed/#findComment-240455 Share on other sites More sharing options...
j hancock Posted April 3, 2014 Share Posted April 3, 2014 Yeah, the low side wouldn't be too bad but the high side would be interesting! Quote JimIt doesn't cost anything to pay attention. Link to comment https://www.bigmacktrucks.com/topic/35281-tranny-ratio-low-speed/#findComment-240457 Share on other sites More sharing options...
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