Just thought I'd share my plan for comment. I have a '68 F-350 which had a FT-391 (w/ 13" clutch) with a New Process 540 5-speed and a Dana-70 for 400K of it's 500K miles. (I bought it from a friend at 500K miles.) Currently I am running a FE-390 and was going to rebuild the 391. I purchased a low-mileage Eaton Roadranger RT-6610 to replace the tired 5-speed. I plan on changing the rear gears from 4.56 to 3.54 along with the Roadranger installation.

I also have a 300 I-6 engine and am starting to think that perhaps I am not in such a hurry that I would need the 391, which will be an expensive rebuild. I am retired and will not ever be in too much of a hurry. I do believe that gears are can be a substitute for cubic inches.

I have two steel scattershield (one for FE/FT engines and another for small-blocks, including 300 I-6) and can make either into the required SAE #2 half-bellhousing in my hobby machine shop. I am currently putting a 240 I-6 into my '61 flare-bed F-100, so the F-350 project is going to be in the planning stage for a while.

I would be interested in anyone's ideas and especially in experience. There is more to my plan, but I'll keep this first posting short and fill in the details as this discussion proceeds.

 

first of all, I beleive that you can find all the parts you need with enough looking. I looked into the same idea behind a 460. 6610 and 6613 came behind 370 and 429 engines in the early 80's. I see no trouble doing the install other than time. A good Ford parts man will be very vauable. They can go back in their books and find a wealth of info.

I'm on the road right now, so check ins will be few and far between. What model NP540 do you have?

 

Elliot,

It looks as if we two are the only Roadranger fans for now. I can be patient on your replies -- I have already had the trans for three years, so no rush.

Here are the my 540's ratios: 7.41 4.05 2.4 1.48 1

It has a Dodge top-cover, which has a taller "tower". This gives it very short throws on the shifter, making shifting require some muscle. The guy that put over 400,000 miles on this trans after he built it also has a big rig and that was the way he liked it. A used top-cover was almost $200, so I decided I could live with it.

Just to anticipate: this big a trans will have more "parasitic drag", but I am willing to give it a try. The 425-pound weight does not bother me going into a 6,500-pound vehicle. I also was looking at an RT-6613, and even watched a RT-613 go for a reasonable price on eBay. I cannot tell you an accurate weight, but have you seen how HUGE the rear section of the "little" 13-speed is? My guess is it is well over 500 pounds. It is also pretty bulky.

It turns out that a 6610 has almost exactly the same gear ratios as my 540 if you skip every other gear, so I know what I will be getting. The 540 with a 4.56 ratio in my Dana 70 is "perfect", with the exception for not having a "going home" gear for running down the highway unloaded. I just purchased a 3.54 ring & pinion, which will solve that. First gear will still be a deep "grannie". The 10-speed will perfectly split every gear which will help a lot on grades and will keep my right arm in shape. I can always "skip shift" when unloaded.

Plan "A" is to use a steel scattershield to fabricate my bell-housing, but I would go with a cast-iron "stocker" if I could get one. I am pretty sure that SAE #2 transmissions, including Roadrangers were put behind 391FT's, but I do not think there were a lot of them. I just need to find one that is for sale. This would allow me to use my 13" clutch, where as the scattershield limits me to an 11"

OH! One installation problem is the shear width of a Roadranger. I will probably have to cut up my floorboards and fab a larger hump. I have the necessary sheet metal tools, so this is no big deal. I'll stick a pic or two of the trans in my gallery.

Enough for now, I'll look forward to more feedback. Archie

 

I'd love to hear more, since I'm putting together a "197something" 350 wrecker and the combo sounds very interesting.
What would be the most likely donor trucks? My odds are decent at being able to snag one going to the scrapyard.

 

Glad to find that somebody in addition to Elliott is interested in Roadrangers.

My RT-6610 is out of a '92 Chevy "straight truck", which I take to be a 2.5-ton delivery truck. A firm in Knoxville, TN, had four of these behind 427 truck motors. They had a lot of driver turnover & paid their service shop to convert them to automatics. The transmissions only had 25,000 miles. (I saw an eBay ad last night for an Eaton trans that said: "ONLY 300,000 miles".) (I bought mine three years ago, so the other three are long gone, going for $500 to $900.)

Some wreckers in the last twenty years used either the RT-6610 10-speed or the RT-6609 9-speed. The 9-speed is still in production and has 35% jumps betweek gears. The RT-6610 is no longer in production, but the 28% jumps appealed to me. I can tell you a lot more, but visit the Eaton site:

http://www.roadranger.com/Roadranger/productssolutions/transmissions/index.htm

Poke around this site - it has a wealth of info, including shop manuals in pdf format, all down-loadable!

For some non-Roadranger ideas, check out my Brownie thread at:

https://www.ford-trucks.com/forums/5...ie-thread.html

 

Thanks for the rapid reply!

Now I can look for organ donors.

 

In the wrecking yard, count the number of bolts along either side of the top-cover. You want 4 bolts per side - that gets you a 425-pound transmission. If you get one of the more plentiful "big brothers" with 5 bolts per side, you will have a transmission that will outweigh your engine. The other similar transmissions are the RT-610 types, which will work, but have coarser gear teeth and, hence, make a lot more noise.

The other thing to look for at the same time is the half-bellhousing that adapts the SAE #2 trans bell to the engine. At this point I am planning on fabbing my own out of a steel scattersheild. What engine are you going to run?

 

The only real drawback I see to this tranny swap would be, I hope you like double clutching, because this is a non-syncro trans. Also, you will have to have an air supply for the air shifter in the back box.

I drove a few of those trannies years ago when I was moving storage vans around Memphis TN. Personally, I would rather have a 5+2 for the application.
As for being a Roadranger fan, I own and drive 2 RTOO9513s, one in my R600 Mack toterhome and the other in my LN8000 Ford service truck.

 

Welcome to the thread, Jeff, your experience will be appreciated.

I have not driven a Roadranger, but I have ridden along a few times. I have had a few different combos over the years: an overdrive I spliced onto a T-10 4-speed and another I put on a T-98 4-speed. The T-98/OD split out pretty well with 8 distinct gears with pretty even spacing. I have admired the Roadranger design since I ran across a good diagram of it in the '60's. I was considering a Brownie behind my F-350's NP-540, which would be pretty good splits, but I am tired of "twin sticking" and I got the 10-speed for a pretty good price.

I learned to drive on a '51 F-1 which had a Brownie, so double-clutching is a skill I have had for a long time. This is not my daily driver, so it will usually have a load on, or I would take my '61 F-100. On a close-ratio box like the RT-6610, it should not be too hard, although I expect to"skip-shift" when empty, so the bigger jumps will be a little harder. I realize I need the air, but only on range shifts, so a small tank & compressor should do the job.

Are your RTOO's double-overdrives? I am swapping out my Dana 70's 4.56 ring & pinion for 3.54's, so I am sticking with a direct top gear.

 

Yep, both of them are double overs. The Ford has 3:70 gears and the Mack has 3:55s, so they will both run well in excess of triple digits. Neither of them are worked too hard though, the service truck weighs 20K and the Mack with the 37" 5er hanging on the rear weighs around 30K.
If I remember corrctly the 6610 is a straight shifting trans, unlike the 6613 which has a pretty weird shift pattern. It has been a long time since I last drove either, so I could be a little confused. Good luck with the conversion and let us know how it turns out.

 

I really appreciate all the engineering features that Fuller put into the Roadranger transmissions. The ability to swap four gears around and change from a direct top gear to an OD or even double over is great. (Think of all the threads on these forums of other transmission owners who want to go OD and have to find another transmission or add an extra auxiliary trans.)

With the "O" and "OO" transmissions, one gets a non-standard shift pattern and I am sure that one can get used to it if driving the same vehicle all the time - the same two in your case. One of the additional tricks that Fuller had up their sleeve was the "X" option that put the shift pattern back to standard, even though the trans was an OD top gear arrangement. I checked out how they accomplished this and was impressed with how elegantly simple their solution is. All they do is float the top-gear shifter fork on its shift rail. Then they have a "selector" that floats on another shift rail with a little 1:1 ratio rocker lever that connects the two floating components. (I know this sounds like greek, but on the diagram it is quite simple - I'll dig it out & post it.) The neat thing is that all this is in the top-cover, so it is a bolt-in swap. (Unfortunately, this option only existed on the big tranmissions, so I am out of luck with my RT-6610.)

I am going to stick with a direct top for several reasons:
o I like the std shift pattern.
o It keeps the drive-shaft rpm's down for less vibration.
o I have to rebuild my Dana 70 anyway & already have the 3.54 ring & pinion.

Pardon my ignorance, but what dimension on your "5er" is 37"?

 

I just found this thread.Interesting. A ranger behind a 391 in an F350. Ford likely used this set up in heavy F or L series trucks.Acheda shifting a Roadranger is kinda like riding a bike, it takes a bit to catch on but from there out you never forget.Once you learn the basics then you can learn skip shifting.This technique comes in handy where you are in heavy but moving traffic and are empty or next to it.Good luck with your swap.I'm gonna keep watching this one.

 

Thanks, Redcat Diesel, I wish that I could promise a little more speed to the entertainment, but even though I am retired, the shear number of outstanding projects seems to be mulitplying. (Doing a complete kitchen remodel for the wife is not nelping, either.) I have the roof off of my '61 F-100 & need to get the new one welded on AND a 240 in it in place
of the 223. THEN I can get to the F-350 (& a lot of non-automotive projects). All the same, I REALLY appreciate the encouragement & feedback.

I learned to double-clutch back in '63 and have ridden along in a few Roadranger rigs, so I am familiar with the rhythm. I have done a lot of 4 + 2 gear-splitting and am eager to do something different for a change.

Regarding the 391, I have everything I need to put it back in the F-350 except the SAE-to-FE adaptor, which I can fabricate myself from a steel scattershield if need be. (Down-side is I would be giving up my 13" clutch.) I have put enough miles on the one-ton with the 390 that is in it now, to put a pretty big dent in my wallet, plus the 391 has been 400,000 miles since its last rebuild, and I know that a complete rebuild is not going to be cheap.

ON THE OTHER HAND, I have a 300 with a brand-new valve job on it which is just sitting there since I got the 240 for the '61. I also have a steel scattershield for it, so I could try it in the F-350 ahead of the Roadranger. I am rarely in a hurry and with the 10-speed I should have the gears to handle any situation. (I hear cheers from the I-6 forum and boo's from the FE forum . . .)

 

OK you caught my typo, was supposed to be 37'. Yeah, a 37" 5er would be a little small.
You mentioned driving 2 identical transmissions would be easy, but in my case you have to remember I have a 6-71 Detroit in the Ford which runs at WOT(2350 RPMs), and a EM6-300 in the Mack which pulls at it's best around 1200-1600 RPMs, so even though they are identical trannys, shifting them is totally different.
During my 20+ years of working on trucks and heavy equipment, I think I have driven most transmissions that were offered. Some are a dream to drive and some are nightmares.

 

Jeff,

I was hoping you were referring to a 37' length. For a minute I thought it might be the diameter of your fifth wheel! (Makes my 12" Binkley seem kind of inferior!) At this point, my F-350 is set up with a disappearing king pin and I have purchased a new fifth wheel, but the fabrication of a "toterhome" is still in the planning stage.

Regarding your engines, I see what you mean. I bought the F-350 from a friend and separately bought the Perkins 6-354 he had planned on installing in it in the 70's. He ran out of time and opted for the 391, which was a Ford factory rebuild and went 400,000 hard-working miles. When I bought it, it was only running on 6 cylinders, so I only drove it a few miles before I stuck in a free 390 donated by a friend.

I finally decided to stay with a Ford engine & got my $$$ out of the Perkins. I doubt that even with an OD & 3.54 rear gearing that I would have a very good top speed with the Perkins. I never saw any mention of doing a double-over with my RT-6610, but my wife also was not happy with the idea of a diesel and every now & then I cater to her desires.