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Hi, I have a 1984 F8000 dump truck with a Cat 3208 turbo powering a RT6613 13 speed. The transmission went out and I want a different setup to where I can still pull my backhoe on my equipment trailer down the road but actually be able to hit 60 mph. The gearing is really low. Any ideas on what transmission would fit with better highway manners? Thanks for your time.
A confusing subject. If you look at Roadranger transmission ratios you can find a site that lists all transmissions and their ratios. OD ratios are expressed in high gear such as .78 or .87 type figures. If you figure out how to read the chart you have lots of choices. You can remove anything over a 9 series from your list because they never made a bellhousing to bolt to your engine. One for a 9 series is also hard to find. Can you can find someone to rebuild your transmission. Press the front two gears off of both counter shafts, swap and press back on. Exchange the input gear ( on the end of the input shaft ) with the front gear on the mainshaft? That gives you about 20% OD and yes may not be on the chart. Then you run the risk of being over geared and don't have the horse power to pull it out. A 9 series 13 OD is about 12% OD and has the advantage of being able to split every gear in high range. Great on the road but it has no LL or deep reduction gears. That's all from memory and probably not much left. You get the idea enough to check it out I hope. If you do the gear thing it results in an odd shift pattern but it works.
We put a RTO9513 in a 83 LT 8000 with 3208T cat, replacing the RT6613, the truck will run 60 mph now, not sure if it has 6.50 or 5.57 gears.
As has been said 9 series is the biggest one can use with the 3208's smaller clutch housing.
9 series 1 3/4" input is also the largest hub size we could find in the 3208's clutch size, 12 series and larger have 2" and larger input shafts.
We did have to make exhaust modifications to clear the larger trans case plus drive shaft mods..
A set of used rears in the 4.60 - 5.30 gear range may be a better option.
One of the newer 6 or 7 spd OD trans is another option.
You can go larger ten a 9 series fuller for the 3208.
Flywheels for 3208 came in 2 sizes2both 14in with a .98 205ss or a 1.18 pilot. If you look up individual eaton fuller transmissions you can get part numbers for #2 bells and input sizes. Ie RTLO16913A (low inertia 13 overdrive) can attach to sae #2 bell A3723, A3721, A3722, A4772, A4344, A4771. In combination with input shaft S1659 which is a 2" - spline and 1..18 pilot bearing. So with these numbers I can take my 13sp overdrive out of my 2015 International Prostar and back it up to a cat 3208 and all I have to change is from a 14" 1.75 clutch to a 14" 2" clutch and swap bell housing. The input shaft is already a s1659 used on isx 15 with 13 speed. These part numbers are also the same for the 18 speed RTLO16918b transmission. RTLO 13 and 18 speed 16 series trans are interchangeable infront of main case
Things may have changed since then but as I had said in my last post we couldn’t find a 14” clutch with a 2” hub
1 3/4” was the biggest 14” clutch we could find at that time
I haven’t looked since then but if I could get a clutch like that I have a nice RTO12513 I’d put behind my 8.3 Cummins
Things may have changed since then but as I had said in my last post we couldn’t find a 14” clutch with a 2” hub
1 3/4” was the biggest 14” clutch we could find at that time
I haven’t looked since then but if I could get a clutch like that I have a nice RTO12513 I’d put behind my 8.3 Cummins
for your rto12513 you could go with a A3722 Bell and A S-1406 shaft 1.75-10 with 1.18 spline
