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Discussion Starter #1
I've been kicking around the idea of putting a 10 speed behind the 12 valve in my '78 D300 for a while now and wondered if anybody has actually done it. I've searched it on youtube and in Google a few times but never actually saw the transmission bolted to the engine. Has anybody on here ever seen or done it? If so, what model/make transmission did you use? How big is it? Did you build your own bell housing? How was the clutch to set up? Is there a smaller 10 speed from an older truck that works better? Any information from anyone that has actually laid their hands on this combination or anybody that knows of a smaller 10 speed transmission would be greatly appreciated. Thanks!
 

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I have seen one thread over the years where a 10 spd was being installed into a 1st gen. That swap is not for the faint of heart. You will be removing a lot of floor board to make it fit. Then rebuilding the floors to cover the massive hole. The seat will need to be raised to clear the new floor boards.

For parts that I remember. You need a SAE#2 engine adapter. For a 5.9 those are hard to find and expensive. You need a clutch for a 5.9 and the small input shaft 10spd. You need the SAE starter. That SAE adapter has provision for a starter on eatner side. So before buying one make sure the starter is on the side you want it mounted on.The trans would be a 6610 if I remember right. You will need to make side mounts for the engine adapter or make a rear trans mount. The RR's are made for a top mount on the trans not the bottom mounts a lite truck has. The clutch linkage for the bell need to be a push to operate not the pull to operate. Then you need to rig the hydro's up. I do not know if the stock dodge hydro's would be able to operate a 13" semi clutch.

I know I have forgotten some things.

There is a thread in the 2nd gen section where a member installed a Spicer 5 spd into one. Read that over good. Then remember everything is bigger on the 10 spd.
 

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drooling piston here on the forum put a 13sp (I think) in a second gen. its been a long time ago. you will need a trans with a very tall overdrive if you want to run very fast on the highway.
 

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not to mention alota torque to spin a much heavier set of gears so gonna needa seriously up the output of that engine thats why ya only run 6 and 7 speeds behind class 5 engines, onea my welders made the mistake of putting a 13 speed behind the 855 cummins (240 hp) in his 85 GMC Brigadere mobile home toter about 12 years ago... the truck had a 7 speed spicer and was pretty decent puller just lacked top end after the 13 it couldnt pull a hill with a travel trailer let alone a 16x80 house.... he endeed up swapping a 400 big cam into the truck... expensive but cured it
 

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Discussion Starter #6
drooling piston here on the forum put a 13sp (I think) in a second gen. its been a long time ago. you will need a trans with a very tall overdrive if you want to run very fast on the highway.
I can already run 70 at 1500 RPM in Overdrive. I obviously don't pull a trailer in OD but it's nice for cruising.
 

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Discussion Starter #7
not to mention alota torque to spin a much heavier set of gears so gonna needa seriously up the output of that engine thats why ya only run 6 and 7 speeds behind class 5 engines, onea my welders made the mistake of putting a 13 speed behind the 855 cummins (240 hp) in his 85 GMC Brigadere mobile home toter about 12 years ago... the truck had a 7 speed spicer and was pretty decent puller just lacked top end after the 13 it couldnt pull a hill with a travel trailer let alone a 16x80 house.... he endeed up swapping a 400 big cam into the truck... expensive but cured it
What gear was he trying to pull a hill in? I see why if he was topped out. Would have to shift down in about anything.
 

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EGTs were through the roof its actually a set of hills on I-10 here in AZ between Benson and Wilcox called "Texas canyon" with his original setup he topped out at 65 mph flat ground, up hill down hill etc.. it was an ex yellow freightlines truck setup for dragging doubles, all of my toters (8) were built on Freightliner FLH condo cabovers with Cat 3406Es in them 6 with 13 speeds and two with 18 speeds he worked for me before buying his own truck all of mine would drag heavy side 14 and 16 by 70s-80s down 10 all day long (literally we load outa the factories in phoenix at 0500 and keep rollin as long as curfews dont catch up to us) at 75mph if we were in a hurry (yea permits say 55 tops not many follow that including the police escorts)
Anyway Morgan gets this truck and is all excited and he was doing ok until... I passed him going up a hill by Dragoon Az in Texas canyon... then the other half of the house passed him... he thought he needed more gears did the tranny swap and after that same truck couldn't hardly pull through the canyon without EGTs going through the roof and the truck was a dog in general.... the diesel salvage yard owner tried to warn him that those extra gears meant extra rotating mass which as anyone whos ever played on a dyno knows requires torque to get into motion... a 240 hp cummins Morgan at 25 decided the old guy who by the way used to build heavy haul tractors for a living... was senile and did the swap anyway.... 2 things he shoulda went low insteada high on the 13 that 240 mighta got it spinnin with some basement gears and 2 he shoulda swapped rears instead but... it did great after he went to a big cam 400, still couldn't catch onea my FLHs if he had a good tail wind but he was much happier as long as them big grey metal flack freight shakers stayed away from him :D
 

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I’ve got a lot of info on my old computer, I’ll see if I can dig it up later. The RT-6610 is physically smaller than the big Eatons, if you can find one, and I also believe there’s an 8 speed single countershaft transmission, which would fit much nicer under the truck. Careful though, many of these transmissions don’t have overdrive. Sae 2 bell housings shouldn’t be too hard to find, every medium duty with a cummins (there’s a lot of them) should have one. The clutch has to be dealt with, custom mounts, on board air for range shifting, and a transfer case if 4x4. Doable, but not easy


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Discussion Starter #10
Definitely want to keep overdrive. No 4x4 to worry about. As far as custom mounts, I had to do that any way for the 5 speed that's in it. If I have to cut it up, no huge issue. I bought a compressor a couple years ago in hopes of putting it on to have live air and for air ride in the future. I had anticipated cutting up the floor but after seeing the difference between my Dad's 74 4 speed 4x4 and my '78 that originally had an automatic, I'm not real worried about running out of room. Tons of foot room at current. If I have to move the seat, might just put buckets in it.
 

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Definitely want to keep overdrive. No 4x4 to worry about. As far as custom mounts, I had to do that any way for the 5 speed that's in it. If I have to cut it up, no huge issue. I bought a compressor a couple years ago in hopes of putting it on to have live air and for air ride in the future. I had anticipated cutting up the floor but after seeing the difference between my Dad's 74 4 speed 4x4 and my '78 that originally had an automatic, I'm not real worried about running out of room. Tons of foot room at current. If I have to move the seat, might just put buckets in it.
A 6610 might be the ticket for you, then. These transmissions come apart real easy, and overdrive gears can be swapped in place. It's a bit of work, but if you're going as far as to put an Eaton in, you might as well get it done. The Eaton Fuller RTLOs and 8LLs, which are the most common twin countershaft 8, 10, 13, 15 and 18 speeds are physically massive. I used to work with them all the time, and I wanted to put an 8LL in my truck. After pulling them down out of tandem steer cement trucks and dealing with them on the ground, I decided there was no way i wanted to deal with trying to fit that nonsense
 

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I run a RTO610 in mine.
I had the Worlds greatest luck in finding one with a SAE 3 housing. The overdrive is only .8
Clutch is from an Aussie International truck, push type and operated by an air assist slave cylinder. You need air anyway for the range change in the box.

I raised the cab 2" and had to modify the fire wall around the clutch housing but as this is a Ford, part of that was to get the engine setback so I had clearance at the radiator.

The 610 has gear noise, believe the 6610 has different gear angles and are quieter, and remember it is a crash box so takes a bit of getting used to.
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The bigger RR's only have a spring support on the rear of the box, I mad up a lower crossmember and used a couple of small mounts to just take the load and there are mounts on the bellhousing.

Tows very well, think a 13 would be a waste, even with 7000 lb of boat I still start in 3rd on flat ground.
Cheers Steve
 

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Discussion Starter #13
I guess I'll start calling around and see if I can find a usable RTO6610. I would like to keep overdrive. What did you have to for clutch? Different flywheel or...?
 

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Most will require a SAE 2 housing and a flywheel to suit. Can dig out some info on the clutches but anything thing from a medium truck will work.
Will dig out the link to a clutch site that is helpful.
There is a 610/6610 on 4BTSwaps for sale.
Cheers Steve

Try this for clutch info, with my SAE 3 I was limited to the 330MM size, SAE2 can be larger.

https://www.iatcoinc.com/product/medium-duty-clutches/
There are various input shafts for the RR but there will be clutch centres to suit without going custom.
 

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I guess I'll start calling around and see if I can find a usable RTO6610. I would like to keep overdrive. What did you have to for clutch? Different flywheel or...?
Go to any big truck dealership and give them the serial number for your transmission and the application if you know what it's out of. They're pretty universal and cheap. You might have more trouble finding a single disk clutch, as everything on the highway runs dual disk
 

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That site I linked shows both single and dual plate options along with the rated torque, input shaft diameter and spline count.
Cheers Steve
 

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Push Type Clutch - brake?

I run a RTO610 in mine.

Clutch is from an Aussie International truck, push type and operated by an air assist slave cylinder. You need air anyway for the range change in the box.
Blackduck59, it is my understanding that if you are using a push type clutch you have no clutch brake. Assuming this, are you using any brake to stop the input shaft? If not, how long do you have to wait before you can shift out of neutral into gear?

I am also looking at installing an RTO6610 behind my Dodge Cummins 6BT 5.9. I would like to use my dodge bellhousing and clutch, but worry about no clutch brake. Any advise or information on the clutch brake would be appreciated.
Thanks, Mark
 

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Discussion Starter #18
If my Math is correct, I could install one of my SM465 Muncie 4 speeds behind the Getrag 360 and use the 3rd and 4th in the Muncie to split the gears in my Getrag. I might end up doing that. If I do, I would essentially have 8 useful gears in before overdrive in the Getrag and I've been advised not to pull anything in 5th and I understand why after having the top cover off 2 years ago.
 

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If my Math is correct, I could install one of my SM465 Muncie 4 speeds behind the Getrag 360 and use the 3rd and 4th in the Muncie to split the gears in my Getrag. I might end up doing that. If I do, I would essentially have 8 useful gears in before overdrive in the Getrag and I've been advised not to pull anything in 5th and I understand why after having the top cover off 2 years ago.
I don't know if the small Muncie input shaft would handle the toque setting behind the getrag. as rpm decreases toque increases per given hp. so if you would be in lets say 3rd with the getrag and 4th with the Muncie that would put the input to a lot of toque.
 

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Discussion Starter #20
I've wondered about that as well but I might build a different one anyway to get the transmissions closer together. I've heard those transmissions stock are pretty stout.
 
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