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Cummins 8.3 & 06 F550

16K views 19 replies 5 participants last post by  savoy64 
#1 ·
OK I have a fresh 8.3 that I can't sell and a 2006 F550 without a power plant. I know it's big but dam it would be a great towing powerhouse. Cut loose you thoughts on this one. I have a full fab shop and can make anything needed. I have a Eaton Fuller 9 speed behind the 8.3 but would want to loose that for a sincro trans, maybe a 5 speed as I wont need a ton of gears. I understand I'm up about 1,000 pounds on weight
 
#4 ·
Cummins says it is 1800 lbs wet, so that is about what my Cat weighs so i say go for it, keep the 9 speed, with the right rear axle (C4500) and ft axle (c4500) or C5500 it has the weight ratings and can get decent ratios, as wel as 4x4 or 4x2
 
#5 ·
Well I pulled out the 8.3 from the L8,000 over the weekend. Now that it's setting out in front of the shop, it looks even bigger. The 9 speed has to go, I need a synchromesh 5 or 6 speed that is a ton lighter and a lot easier to shift. Any ideas on what trans that will bolt up & is prefurably overdrive ? I have access to a rebuilt Allison MT653 PM I understand that is no overdrive so I would need to do a gear change. The tallest gears for the 550's rear is 3.08
 
#6 ·
what is the tq of the 8.3 that you have? for an eaton OD the FSO i think are OD, the RTO i know is OD and RTOO is a doubel OD
 
#8 · (Edited)
well i just did a quick ebay look and most of the 6 speeds are rated for 600 tq, the 9+ speeds are better for 600 and over. got pics of your project so far?
here is a 10 speed sycnronized and OD
http://www.ebay.com/itm/Reman-Eaton...Parts_Accessories&hash=item4603e3f87f&vxp=mtr
FRO15210B+
Fuller rage rover Overdrive
1520 lb/ft tq
10 speed
revsion B
can be shifted as a 5 speed,6 speed,7 speed,8 speed,9speed or a 10 speed
 
#9 ·
I understand the ratings for torque. There is no way to put that big trans in this truck. The big trans weigh over 650 pounds and are designed for loaded weights of over 40,000 pounds. My truck and trailer are never going over 26,000 so the actual torque load on the trans will be far lower than your thinking. Years ago I had a Intl with a DT466 with a simple 5 speed, it shifted great & I know a lot of Ford trucks with the 8.3 had 5 & 6 speeds. Using the 8.3 puts me up about 600 pounds and the big trans would make this a no go at 400 + more. I would break u joints and axles before reaching the strength threshold of a heavy duty 5 or 6 speed.
 
#10 ·
Thanks for your encouragement, I have the L8,000 in my home driveway and have to cut it up and get it to the scales before I can bring the F550 home from my shop & began the conversion. The conversion will be stalled until a suitable trans is found as I can't even mock it up without one. I hope to cut the L8,000 up this weekend. I will take some picks this weekend of the puzzle
 
#11 ·
the IH 466 used a 6+1 tranny that might work behind the 8.3 esp since you will not actually be wroking the piss out of the motor. not sure the model number tho. the 6406? might work as wel i dont know how strong the eatons are over there ratings
 
#13 ·
I now have the 550 home & ready to start the conversion. I finally sold the 8.3 & have a 5.9 with a Eaton FS 5306 ready to go in. I found that I have 488 rear gears, what was Ford thinking? It's very expensive to change the gears so I need to get that right the first time. Anyone here that can make a educated guess on what gear is best. 90% of all driving will be highway speeds at 70 mph, trans has no overdrive. Truck & trailer will be max at 20,000# total. truck has 225/70X19.5 tires. The tallest gears are 308 according to what I have found, This rear is the big Dana/ Eaton S110 Will the taller gears fit this carrier ?.
 
#14 ·
Well i am planning on the sam kind of setup. A 3.08 woul keep rpms at around 1600 at 70 ish
 
#15 ·
Well it appears that everything is back on hold as the tallest gear made for this rear is a 373 !! I'm stuck with 225/70/19.5 tires which are around 31 tall. With a 373 gear I must have overdrive. I don't think the FS5306 can be converted to OD. I can't see dropping big $ for a Eaton OD. I think it would be smarter to use a ZF 5 speed and adapter. Any ideas ? Even if I can find the older Dana 80 the 340 gear is not much better.
 
#18 ·
Oops sorry,witha achange of carrier you can go up to a 5.xx,6.xx and i think a 7.xx
 
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