Hey guys, I have a 1984 IH s1824 4x4 single axle with the huge 20,000# winch on front. Quad cab. Someone took out the original engine and dropped in a Ford 460. It still has the Clark tranny with PTO for the winch. I'm trying to get the RPM's down and top speed up. It's cranking close to 4k @ 60. I need this truck to be a highway machine as it will be used to transport my toy to off-road parks. Im looking at a rusty 1981 IH (still trying to get the model) single axle truck that has a DT466, dana/spicer toploader 5-speed (anyone know if it has PTO provisions?), and 2-speed rear. I would love to drop in the DT466 and possibly keep the 2-speed rear, but I can't find much info on what gears my 1984 has. It was originally a gasser. The tranny has a granny, no OD... this thing is geared incredibly low, which is normal for the gassers, but I need to know how low to see if the low rage in the 2-speed would be low enough for 4wd. Will the dt466 mate to my clark? Any info would be appreciated! I'm very new to medium-duty trucks.
What I did with my 2000 7.3 F550 Ford 4 wheel drive quad cab with to low of gears (62 at 2400) was to install a 3 speed Brownie auxillary tranny where the rear carrier bearing was. I now run 74 MPH at 2400 RPM. I made a simple linkage to shift from direct to high. I do not use the low side. Only thing to remember is that you have to be in direct on the aux to use the 4 wheel drive to avoid some serious gear bind. I have put just under 50 thousand miles on mine and have just pulled it out to go thru the bearings as it is starting to whine a bit. It was well used whem I put it in.
AFAIK, 4.88/6.64 ratio is common for diesels and 5.57/7.17 is common for gas, not really much difference. Jack up a wheel and do the math to figure out what ratio you have now. I wonder if the 460 kept it's own bellhousing and that bolted up to the Clark transmission? I don't know how else a ford would swap an ih, not an expert on either though. And since I'm guessing already, any medium duty transmission I've seen has a pto plate. The real question is how well is a 4x4 IH going to ride at 65? And since you're going to all this work, why not get an overdrive transmission? unless you go with the auxiliary trans. Check this out: HeavyEquipmentForums
I will look into the Brownie. My truck doesn't have a 2-speed rear. It is 4x4. I have never seen a 4x4 with a 2-speed rear, but I haven't played with many. The 460 has it's own bell housing and clutch. The clutch linkage needs some help from the 460 being jammed in there. It is connected to the Clark with 2 very thick pieces of torched plate. The truck drives great at 65+. I drove it to south Texas from Amarillo, took me 2 days, but was screaming it at 65 most of the time. When I got on I-10, I pushed it to 70 most of the time. The truck is a great driver! I love it, I would rather drive it across the country than any other regular truck or car I have. getting 4 mpg is terrible. Would getting a line ticket for my truck tell me the gear ratio? Jacking up a wheel isn't super easy right now. I live in the swamp and it has been sitting in the yard for a year. 460 needs a hotter coil and won't run for me without a lot of help and I don't have the time or desire with that stupid 460.
I haven't seen many heavy 4x4 either, this is mostly over my head. You could try looking for a tag on the axle for the ratio, it might still be there if the truck came from Amarillo.