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I ended up finding a NOS old school RTO-613 chrome roadranger A-4488 shift knob after 3 months of searching. Super cool old school find. Also, I bought a 1940 D35 international 1.5 to 2 ton truck which has 6 inches more hood than my D30. I'll swap the body onto a more modern 83 chevy K30 chassis and stretch the frame a few feet.
 

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Regarding the 205 transfer case idea have a look at the beginning of this thread where I also considered it behind an RTO-6610 and 6BT.
http://www.4btswaps.com/forum/showthread.php?26143-05-F250-98-5.9-Cummins-and-a-roadranger-RTO6610&p=217009&viewfull=1

Seems the general wisdom is while it is well regarded in the gas engine world it would not likely hold up to a good 6BT, and the about 10:1 low gear on the Roadranger wouldn't help matters any.
I know of two trucks with 6BTs, NV4500's, and NP205's. One is a burb that rarely tows anything, while the other is a Chevy crew cab dually with 37" tires that ALWAYS tows heavy. So far, neither has had any issues with the 205 even after years of use. Also, 1st gen Dodges with the Getrag ran 205's.

Two things to keep in mind: First, all of these 205s have the late style output shafts which are much stronger than the early shafts, and they are right hand drop cases (Chevy and Dodge) which are known to be stronger vs the left hand drop (Ford) case. Second, there is no question that the 271/273 can handle more torque. The choice depends on availability and what you're doing with it. 241's aren't really a bad choice, either.
 

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I know it's an answer to an older post but...

I've heard the 600 series transmissions may date from the late 70's and the 6000 series came along in the mid to late 80's, my 613 came behind a 3208 turbo in a little ford dump truck. 3208 went poof!

Also, the 205 is a great transfer case but, gets into some thrust issues under extreme torque. I blew the output through the rear bearing retainer on my 92 dodge sled puller a few years ago. After that the rear output likes to shear at the oil slots. There is a bigger output made from a dana 80 pinion, after that the case scatters.

The NP241/241HD are actually pretty strong despite the aluminum case. The planetaries eliminate alot of the thrust problems the 205 has as long as you keep a good chain in it. They were available as a drivers/passengers side drop dodge/chevy and a passengers drop fixed rear output version in 87-93 dodge gas pickups. However there was a design change in the planetary gear tooth pitch in 1994 so later inputs like the 29 spline dodge won't work right. So, 32 spline GM is it for now unless someone steps up and makes one 29 spline in early pitch on 31 spline big ford in early pitch.

The real option might be the NV271, its a beast. They only are available as dodge or ford drivers drop. I'm looking at flipping a ford fixed output unit to make it passengers side drop and reworking the oil pump pickup. This is common in sled pulling trucks but, I'm not endorsing it on the street yet. One of the ford input sizes available is a 31 spline which is the same size as a 2wd dodge diesel NV4500, this is larger than the 29 spline input on the 4x4 dodge diesel.
 

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I know it's an answer to an older post but...

I've heard the 600 series transmissions may date from the late 70's and the 6000 series came along in the mid to late 80's, my 613 came behind a 3208 turbo in a little ford dump truck. 3208 went poof!

Also, the 205 is a great transfer case but, gets into some thrust issues under extreme torque. I blew the output through the rear bearing retainer on my 92 dodge sled puller a few years ago. After that the rear output likes to shear at the oil slots. There is a bigger output made from a dana 80 pinion, after that the case scatters.
Ford cases (driver drop) are weaker than the Chevy/Dodge (pass. drop) cases due to the location of the PTO opening. I've seen a few broken Ford cases, but never seen a broken Chevy/Dodge case. Also, as I mentioned in a previous post, the later outputs with small oil openings are much stronger than the ones with 3 large openings. Keep in mind I'm talking from the POV of off-roading. For off-road use the gear cases seem to be more durable than the chain cases. They also have the advantage of being twin-stickable, which lets you do front digs, and run in front drive only. Not useful features for sled pulling or drag racing, but it comes in handy off road at times. Like I said in my previous post, which case is "best" really depends on what you are going to do with it.

The NP241/241HD are actually pretty strong despite the aluminum case. The planetaries eliminate alot of the thrust problems the 205 has as long as you keep a good chain in it. They were available as a drivers/passengers side drop dodge/chevy and a passengers drop fixed rear output version in 87-93 dodge gas pickups. However there was a design change in the planetary gear tooth pitch in 1994 so later inputs like the 29 spline dodge won't work right. So, 32 spline GM is it for now unless someone steps up and makes one 29 spline in early pitch on 31 spline big ford in early pitch.
I agree about the 241. I ran one with a SYE and it never gave me any issues. They will eventually stretch a chain, but a good Morse or Cloyes chain lasts quite a while. Biggest issue off-road is that the planetaries dont get much oil during continuous low speed travel because the oil pump is being spun too slow. Also, the aluminum cases are relatively fragile, so a skidplate is a must.

FWIW, there is an early wide-bearing 29 spline input available. Also, it was the helix angle that was changed, not the pitch. It's hard to see unless they are side by side. Biggest giveaway is the width of the bearing seat: the early ones are nearly an inch wide (.940") while the later ones are closer to 5/8" wide (.640").

The real option might be the NV271, its a beast. They only are available as dodge or ford drivers drop. I'm looking at flipping a ford fixed output unit to make it passengers side drop and reworking the oil pump pickup. This is common in sled pulling trucks but, I'm not endorsing it on the street yet. One of the ford input sizes available is a 31 spline which is the same size as a 2wd dodge diesel NV4500, this is larger than the 29 spline input on the 4x4 dodge diesel.
Ford uses a 34 spline input behind their diesels. Big sucker! Also, FWIW there IS a passenger drop 273. It's a divorced case that was used in the GMC/Chevy 4500/5500 (i.e. Kodiak) 4WD models for two whole years. This makes it rare as hen's teeth.

Are you going to mod the pickup externally? The flipped 271's I have seen used external plumbing to solve the oil pickup issue. Seems to work fine, even for a street driven truck.
 

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Ford cases (driver drop) are weaker than the Chevy/Dodge (pass. drop) cases due to the location of the PTO opening. I've seen a few broken Ford cases, but never seen a broken Chevy/Dodge case. Also, as I mentioned in a previous post, the later outputs with small oil openings are much stronger than the ones with 3 large openings. Keep in mind I'm talking from the POV of off-roading. For off-road use the gear cases seem to be more durable than the chain cases. They also have the advantage of being twin-stickable, which lets you do front digs, and run in front drive only. Not useful features for sled pulling or drag racing, but it comes in handy off road at times. Like I said in my previous post, which case is "best" really depends on what you are going to do with it.



I agree about the 241. I ran one with a SYE and it never gave me any issues. They will eventually stretch a chain, but a good Morse or Cloyes chain lasts quite a while. Biggest issue off-road is that the planetaries dont get much oil during continuous low speed travel because the oil pump is being spun too slow. Also, the aluminum cases are relatively fragile, so a skidplate is a must.

FWIW, there is an early wide-bearing 29 spline input available. Also, it was the helix angle that was changed, not the pitch. It's hard to see unless they are side by side. Biggest giveaway is the width of the bearing seat: the early ones are nearly an inch wide (.940") while the later ones are closer to 5/8" wide (.640").



Ford uses a 34 spline input behind their diesels. Big sucker! Also, FWIW there IS a passenger drop 273. It's a divorced case that was used in the GMC/Chevy 4500/5500 (i.e. Kodiak) 4WD models for two whole years. This makes it rare as hen's teeth.

Are you going to mod the pickup externally? The flipped 271's I have seen used external plumbing to solve the oil pickup issue. Seems to work fine, even for a street driven truck.

I have 2, 271 cases here that I started to flip. A friend tigged and sealed an NPT weld bung in the back of the front output area of the case to allow it a draw point when it is flipped. For street use I think a stainless braided line would probably be a must. I was working on a cleaner way to make the suction tube exit the case when I started on the shop. I'm a little skeptical of a flipped 271 on the street, I haven't seen one in a daily driver, much less a truck that someone might possibly run 12-14 hours on I-80. I like to get my trucks out and run them.

The GM 273 is interesting, it's not hard to make an auto shift 273 into a manual shift 271 if you get one cheap out of a wrecked truck. FWIW, I like the monster fixed output on the ford 273/271, I think it can probably handle the 14:1 reduction the RTO-613 can lay down in way low. The 34 spline diesel input would be a nice find if it is indeed larger, but I'd need a scrap transmission output shaft etc the same spline to make an adapter out of.
 

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I have 2, 271 cases here that I started to flip. A friend tigged and sealed an NPT weld bung in the back of the front output area of the case to allow it a draw point when it is flipped. For street use I think a stainless braided line would probably be a must. I was working on a cleaner way to make the suction tube exit the case when I started on the shop. I'm a little skeptical of a flipped 271 on the street, I haven't seen one in a daily driver, much less a truck that someone might possibly run 12-14 hours on I-80. I like to get my trucks out and run them.
If it's picking up and pumping oil I don't see an issue.

The GM 273 is interesting, it's not hard to make an auto shift 273 into a manual shift 271 if you get one cheap out of a wrecked truck. FWIW, I like the monster fixed output on the ford 273/271, I think it can probably handle the 14:1 reduction the RTO-613 can lay down in way low. The 34 spline diesel input would be a nice find if it is indeed larger, but I'd need a scrap transmission output shaft etc the same spline to make an adapter out of.
Or you can have a gear and spline shop make you a coupler.
 

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Discussion Starter #267
These last bunch of post about transfer cases have little if anything to do with Eaton and Fuller transmissions, the subject of this thread.
Please stay on topic and start another thread if necessary.
 

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I've been doing quite a bit of reading and can't find the answer specifically stated anywhere; can a RTX top cover be put on a RT610/6610 after doing the OD kit to give the normal direct shift pattern where the top gear is at the bottom right? It appears that all the covers share the same basic bolt pattern but I was hoping someone here might have done the swap before. I figure it would be nice to eliminate the clumsy shift and go to normal pattern if possible. As much as I'll try otherwise, I'm sure someone will drive my truck at one time or another and it will be one less odd characteristic to have to explain to someone LOL.
 

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I am pretty sure (and I apologize that it is only "pretty sure") that the baby transmissions, the 6610, 6609, 8609, 6613, and 7608ll use a different shift rail housing from the full-size road rangers (part S-1805, no longer available). The lever towers are all interchangeable, but the top cover with the shift rails is smaller for the smaller transmissions. And no X style cover was ever made for the baby housings.

Someone please correct me if I am wrong.
 

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Interesting thread

I have a RT-610 which is belching fluid from the front seal, which in this case is the rear seal since its mounted behind the pumpkin.

Is there a way to replace the seal without pulling it out of the vehicle ?
 

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Depends, I take it you mean the output shaft seal?
If you have enough room when you drop the driveshaft you should be able to remove the flange and change the seal.
It will be tight, 500ft/lb. Either need to pull the top cover and lock 2 gearsets or make up a plate to bolt to the output flange and weld/bolt a lock bar to jam against the chassis.
Will also need to check if it is just the seal or excess wear in the bearings.
Cheers Steve
 

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Depends, I take it you mean the output shaft seal?
If you have enough room when you drop the driveshaft you should be able to remove the flange and change the seal.
It will be tight, 500ft/lb. Either need to pull the top cover and lock 2 gearsets or make up a plate to bolt to the output flange and weld/bolt a lock bar to jam against the chassis.
Will also need to check if it is just the seal or excess wear in the bearings.
Cheers Steve
There's plenty of room around this thing so I should be able to get a big cheater bar in there, thanks ;--)
 

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Measured the nut on a trans I have, came up at 2.277" which is odd, 2 17/32" across the flats. Would have thought it was 2 1/4" Either way a big socket.
Some of the others may chime in and confirm socket size.
Cheers Steve
 

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6610 are a modern upgrade with slightly higher torque capacity, finer pitch gears.

I have a 48" pipe wrench I use for holding u-joint yokes.

Ed
 

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So pulling into town my speedo went flat and I think I found the problem.

P1060036.jpg

It looks like I need to clean it up in there and find a new cap and speedo cable.

Any ideas on where to find that stuff. Its an RT-610.

Where do most of you folks go for parts on line or in Denver ?

Thanks
 

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Helpful Information

Hey guys, there seems to be a lot of recurring questions on this thread regarding size and torque capacity of various twin countershaft transmissions.

Here is a spreadsheet (downloaded from the Roadranger literature centre, which I will re-iterate how helpful it is on Grigg's behalf), which gives info on all except the earliest boxes (gives 6610 but not 610 or 510).

Chart B is the tab I tend to use the most, and there are tabs on yokes, clutch housings and speedo parts as well.

If the link doesn't work, please let me know and I will fix it.


https://drive.google.com/file/d/0B72PfNmcqcZUZ3RVY1lDRGRKRlk/view?usp=sharing
 

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So pulling into town my speedo went flat and I think I found the problem.

It looks like I need to clean it up in there and find a new cap and speedo cable.

Any ideas on where to find that stuff. Its an RT-610.

Where do most of you folks go for parts on line or in Denver ?

Thanks
I just ordered a bunch of parts from Liberty Truck and Auto Parts, EXTREMELY fair prices and they are great to work with. They are only place that could get me an aftermarket OD kit K1671 for my RT610 for only $290. New S1255 input shaft was only $56. Email them at [email protected], very quick to respond.
,
 
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