ArdWrknTrk Posted March 8, 2021 Share Posted March 8, 2021 Jim, you don't use a spreader on the 10.25" Sterling, the Dana 60, yes. I doubt he has a 9", the 460s were only put in the over 8500 GVWR trucks from 1983-1997. As for pulling power, Darth does quite well with the 3.55 gears and the original owner bought him for towing large horse trailers (four or more horses). I pulled a 10K 5th wheel with him and towing he actually got what is normal for an unloaded French 454 truck, 8 mpg. Welcome to our little "asylum" and we will try to help you with information and resources. Did Jack say he had an 85 1/2- 86? Because before the running change in '85 M.Y. he would have had a D60 with left hand studs. But maybe I missed it? I'm definitely not seeing the forest for the trees sometimes. Link to comment Share on other sites More sharing options...
Jack Boetjer Posted March 8, 2021 Author Share Posted March 8, 2021 Jack - Dave is right. This won't be cheap nor easy. And there may be less expensive alternatives. But first, we need to know a lot more about your truck. Please tell us if it is an F150, 250, etc. What transmission. What size tires? Etc. As for other possibilities, you could put an overdrive between the transmission and the transfer case, which would reduce the engine speed. But there's the cost of the OD unit as well as new driveshafts. Another possibility is an overdrive transmission. In the case of a 460 you are pretty well limited to a ZF5, but that would actually work out fairly well. If you go to Documentation/Driveline/Calculators and put in 4.56 for the axle ratio you'll see that with 33" tires you'd be turning these RPMs at 65 MPH: C6 transmission: 3300 RPM T19: 3000 RPM ZF5: 2300 RPM 2300 RPM is not slow, but it is almost exactly what a truck w/a non-OD transmission and 3.55 gears is turning at 65 MPH. Yep, my Big Blue did that RPM for many thousands of miles before I installed the ZF5. And compare that to the 2700 RPM you'd be turning with a non-OD manual transmission or the 3000 RPM you'd be turning with a C6 - if you only went down to 4.10's. So, a ZF5 swap would be something I'd consider were I you. It might be less expensive and would sure be more flexible than going to 4.10's. But, again, tell us more about what you have now and what you want to do. Howdy Gary. Thank all yall for the helpful comments and here's a little more about the tuck. its a 1986 F250 XLT Lariat with a C6 tranny, 10.25" sterling rear axel, 4x4, with a beast of a gas guzzling 460. i'm planning on putting some larger wheels and tires on the truck, 33s, and I ran it up on a calculator which also put out 4.10 as I expected. I Also heard that im supposed to put a slightly lower gear in the front for 4x4, something like a 4.9? concerning the ZF5 swap, I would love to have a manual in my truck, however I don't have a doner truck for parts. I would love the truck to have a little more... yk get up. she's a torque monster and with a change in gears maybe that would help with some of the lack of a quick acceleration. I will be driving this truck to school aswell, which is only about 10-15 miles away, so a little better gas milage that a manual tranny and smaller gears would be greatly beneficial. Link to comment Share on other sites More sharing options...
Jack Boetjer Posted March 8, 2021 Author Share Posted March 8, 2021 Scott, that was the way the superduty welding rig was set up. 460/4.56 It is not uncommon, but 4.56 is more common with real truck tyres. (19.5, 22.5, etc) The questions about lift, and rolling circumference are well noted. Another thing to point out is this is above the carrier break. So, the LOWEST ratio he can go is 4.10:1. Beyond that he might as well just swap the whole axle and sell these to someone who's rock crawling or wants huge tyres. would swapping axels be a good idea in my circumstance? all im trying to do is make the truck less of a hauler (and I know that I probably shouldn't have got myself a 460 then but it was what was available lol) and just an overall better truck to drive regarding acceleration and speed. I responded to Gary about all the specs of my truck if you need em. Thanks! Link to comment Share on other sites More sharing options...
ArdWrknTrk Posted March 8, 2021 Share Posted March 8, 2021 would swapping axels be a good idea in my circumstance? all im trying to do is make the truck less of a hauler (and I know that I probably shouldn't have got myself a 460 then but it was what was available lol) and just an overall better truck to drive regarding acceleration and speed. I responded to Gary about all the specs of my truck if you need em. Thanks! You want to run 33's behind a C6? Like Bill said his 3.55's are fine for hauling. 3.73's are another option. But either one will require new carriers and setting up from scratch. Two R&P sets... Carrier's another $250 each. Plus a Master kit for each axle. Plus a whole bunch of shims -and- time with marking paste. Ultimately you will be time and $$$ ahead to swap axles and sell these on, to someone who needs deep ratios. I have 4.10's from the factory with stock 31ish tires. Overdrive has me turning 3k @ 80 Link to comment Share on other sites More sharing options...
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