NHDiesel

I asked a similar question a little while back without any real response, so I'm giving it another shot. After running my truck for a couple months with the auto, I know that it has to go. I'm just a manual guy, so I'm doing research on other options. Please don't suggest that I get another truck...I only have aprox. $1200 into my '96 including the purchase price, brakes, and replacing the interior. There are also some paperwork issues keeping me from being able to sell it, so its mine for the long haul.

I have swapped autos to manuals before in a couple of my previous vehicles, so i know the basics and whats involved. I can easily source the pedals and hydraulic parts...thats not my problem. If I do go with a manual, I figure that I might as well do it right, so I was wondering if anyone had any tips or info about possibly mating a transfer case ot the back of a larger transmission, such as a RTO6610 or something similar. Because my truck is a standard cab, length is an issue, otherwise I could use a divorced t-case. Who knows...maybe I could anyway, I haven't taken the measurements. But it would make things much nicer to be able to mate a t-case directly to the back of the transmission.

I know shifting will be slower than an NV4500 or 5600, and the installation will take more work, but again...that doesn't bother me. I have machining experience and a fair amount of fabrication experience, so the mounts won't be an issue. Of course the front driveshaft clearance will need to be checked, but the biggest hurdle will be attaching the t-case. I don't have a transmission yet, and I haven't done much work that style, so I can't look for myself to get ideas. I did see another thread with similar questions, but the replies didn't cover the transfer case side of things, just transmission selection.

Jim

RedRotors

I was looking to do the same thing, i have a 5spd, but i tow extreme load ( that's why im adding an 3rd axle ) I looked around and the price is quite high for this type of tranny. Bell housing might be a problem to adapt as well as the t-case..

Maybe someone will chime in with infos..

Cheers,
Marc/

NHDiesel

The transmission costs aren't a problem...I have several sources for larger truck parts, and I know I can get a medium duty tranny for $200-$500. Its trying to mate up a t-case that should be interesting. I know I can get rebuilt autos, but those run several grand. Even an NV5600 would set me back more than twice what I have invested in my whole truck. I don't tow very heavy loads (at the moment) but I want to know that my drivetrain will hold up to it if/when I do have to drag something heavy. And while I'm doing a tranny conversion anyway...might as well go heavier. If I already had an NV4500 or 5600 in the truck, I wouldn't bother with anything stronger right now.

Jim

winkle

You can try these people for adapters. I don't know if this is what your looking for.

http://www.advanceadapters.com/

http://www.novak-adapt.com/catalog/e...s_adapters.htm

NHDiesel

Those guys wouldn't be much help to us diesel owners. AA pretty much deals with popular engines and the Atlas transfer cases, and Novak is pretty much just Jeep. I need to get out and check some of the truck boneyards to see if any of the medium duty transmissions were ever bolted to a t-case. I have checked out several AWD medium and heavy duty trucks around here (benefit of living this far north) and all have divorced transfer cases. If I had to go divorced, I think I'd check out the t-cases in older Ford trucks. Cast iron, gear drive, and very strong...just what I would need. I just hope they would be strong enough for a slightly beefed up Cummins (another reason I want a manual...so I can get the TST kit without worrying about my transmission).

Jim

Haulin_in_Dixie

Well I have some information that might help. RT610 or 6610 is not to hard to find and not too expensive. You need the RTO, that presents a problem. They were made but rarely. You can get a RT 610 pretty cheap and add the overdrive, but that is over 500 for the kit and requires a tear down of the front box. It is really not hard to do but a book is really needed unless you have done it before. I have a RTO 613 that I went OD on.

Transfer case, would probably be much easier and cheaper to go divorced. You may also want to get the speedo sender for the RR and use it instead of the rear axle deal. You would need to look into that. One of the more popular sources for the 6600 trans is the Cat engined four axle dump trucks, that is with the 3208 sized engine.

Ok getting it in the truck. I doubt that you have the floor room if you don't raise the cab, the trans is twice as wide as the stock model. The hydraulic clutch, now I have not done this, but I have info from those who have, that it is not too hard to use the stock slave cylinder and make the brackets to bolt it to the RR. Definately a fab it up job. But the system is supposed to work ok. You will need the commercial bell housing, flywheel, and starter. The starter will be on the opposite side so it will take some wiring changes.

I plan this change and might not get to it, getting old, I have the bell which came on my engine. You will have a mount engineering problem. The engines that use this transmission use a front mount and side mounts on the bell housing. The dodge uses side mounts on the engine, half way back. I would be proper to fab up a rear mount for the trans, but there is not a stock system for this. There is a two bolt pad on top of the rear, but this was what they called a steady rest to take up vibration, not to hold the weight. Some fab work here probaby a set up off the rear housing bolts would be made.

You will need to measure for the gear stick. The stock top plate may put the stick too close to the seat with the console, or even behind the front edge of the seats. The stick will have to be modded, it will be long. Some units use a vibration dampening stick like the Dodge and it may or may not work for you, adds some bulk. If you can find one in the junk yard, they do make a forward shift lever top plate that puts it a few inches forward. You will need an air supply for the range shift, they do not use much if the system is in good shape. I ran one off the spare tire for a week or so at a time before refilling the spare.

YOu may already know a lot of this but will go there anyway. The 600 series is louder on gear wine, more noticable with the OD. The strength of either is good. The 6000 series is a little bit quieter and slightly stronger. Shifting is the same, the gears are not meshed on a shift and have finer teeth on the 6000. The OD makes the shifting somewhat more difficult for clutchless, but not a problem. The non OD shifts easier because the countershafts turn much slower. Some of the older units have a gear rattle in neutral that is not a problem, just annoying.

Don't get involved with the RT613 or 6613 as the rear box is the same as the RT915 and is quite big and heavy. You will have a large drive shaft difference in the yokes, but a shaft shop can make up the shaft with the large yoke on the front and the Dodge yoke in the rear, it will be smooth and work right. Much cheaper than finding and purchasing a small yoke, they are expensive.

I will also say that the 5600 with the SBC clutch has handled my heavy loads just fine.

NHDiesel

Thanks for the excellent info! I would rather have too much info than not enough. I had already thought about many of the things you mentioned, but I appreciate the info and suggestions.

- Transmission selection. I haven't worked out the numbers, but I may not *need* an OD, although it would be nice. I'm 95% sure I have 3.54 gears, and I want to go to taller tires (35") in the future, so i think they will help to offset the lack of OD. I need to run the numbers to see just how much offset they will make. I'm also not familiar with many of the medium duty transmissions, so I don't really have any preference, other than finding one light enough. From what I have read, I should be able to find one under 400 lbs. If I don't have OD, I would have a much easier time finding a cheaper, older transmission.

-T-case. Thats what I was thinking (divorced) but I want to keep my options open, and see what I can find out about trying to adapt my t-case (or another one) to the rear of the tranny.

-Bellhousing won't be a problem...I can get one while shopping for the tranny. I figured I would either have to do a body lift (I won't go over 3") or modify the floor. I'll know more if/when I have a transmission on hand. Tranny mount shouldn't be too difficult...as you said, i can fab something up to bolt onto the tranny and mount to the frame with rubber bushings.

-Air supply will be covered. I plan to install onboard air using a York compressor, but if I don't have that in by the time I do a transmission, I can use an electric compressor from a Caddy air suspension system plumbed to a 1 gallon air tank I have. I didn't think they used much air, but thanks for letting me know for sure. I can bend the shifter as necessary to clear the seat, or even remove the center console to give more room if necessary. I would like to do something custom there in the future anyway, but who knows.

I have to seriously think about all of this before I actually do it. My truck has 230K on it, and I know it won't last forever. I hate to invest too much time and money in a high mileage truck. In this area, the value of a Cummins Ram is the engine...once the engine goes, I could find a whole, low mileage truck to buy for the cost of an engine, so replacing it doesn't make any sense. Of course if I put all the work into a custom truck, I could always buy a used part's truck for the engine and sell off whats left, if and when the time comes. Lots to think about...

Jim

Haulin_in_Dixie

See by my signature, I go about it the other way around. If you should lose the engine, do go for a full commercial engine of the RV sizes, ie RV275 or ISB300 which is a fire ambulance engine. It's a kick running past the "large cars" up a mountain while weighing 30,000. For an example, I run stronger loaded at 30k gross than I used to empty at 14.5k. And better mileage to boot. It is easier to find a commercial engine than a Dodge.

NHDiesel

I just crunched the numbers, and going from a 30" diameter tire (245/75/16, what I'm running now) to a 36" tall tire (which i should be able to run with a levelling kit, since I like narrow tires, and the biggest problem with taller tires on Rams seems to be the width) works out to about a .83 overdrive effect by going to the taller tire. If I remember right, the NV4500 has about a .8 overdrive, so the tires just about make up the difference. I should be able to run an RT610 without an overdrive and have about the same highway RPMs as I have now with stock tires. Thats one hurdle out of the way, with several more waiting to be dealt with.

Jim

Haulin_in_Dixie

Well look at it this way. Get the installation done and you can always do the .8 od in the front box if you need it. Lose one gear on the bottom and gain it on top. That is the way it works. You exchange the fourth gear set with the countershaft drive gears. This speeds up the coutnershafts one gear and fourth becomes an overdrive. If I do it, I might add the weight and go for the RTOO913, air shift splitter with a heavier Dana 135 rear, down about 4:56. That is OD in the front box and OD in the back box. Does not cost anything to reverse those gears like the 600 series.

RedRotors

Thanks for the infos Haulin.. On my side, i don't mind for now to loose the 4x4 on my truck. I even disconnect the vaccum line for the front axle to use the t-case in low range to give me an hand while towing. My main problem is to located a med-duty tranny. I looked around in truck junkwards and they all want to rip me off with the price..

As i spoke with Jim, i can also fab anything needed even machining parts.. I`d like to get with a 10 spds, do you have any advice ?

I add a link with many Fuller tranny. hope this help you guys..

http://www.metaris.com/pto/FULLER.pdf

Marc/

NHDiesel

RedRotors,

Save yourself a little hassle with the 4x4 vacuum lines. Go to a boneyard and look for a Grand Wagoneer (the big, old style Jeep wagons...usually with woodgrain on the sides). Under the dash of many of them are a toggle switch for engaging 4x4. They used a vacuum operated transfer case, and the switch has 3 ports on the back and works great to operate front axle disconnects. Follow your disconnect lines up to the firewall of the truck and cut them, and run them to the vacuum switch. The switch uses one input (from a vacuum source) and 2 outputs (engaging and disengaging 4x4). Very easy to rig up, mount the switch anywhere you want. Then just use it like a cheap version of a Posilock (although not as good).

I have a question about the Fuller info. For the 610, it states "maximum output shaft speed: 2500 RPMs" Since that transmission is direct drive in high gear, the output shaft will be spinning at engine speed...and our Cummins can go over 2500, especially if hooked to a non-OD transmission. How accurate is that statement about max. speed? I know we wouldn't be spending any real time at 2800 RPMs in high gear, but getting up there is possible.

Thanks for the EXCELLENT info charts! I need to go over it more when I have more time.

Jim

RedRotors

Jim,

Thanks for the hint for the vaccum switch, i'll make a trip to see if i can located one, at least, i will install something else, because it's a pain to crawl under the truck to mess with the hose..

I need to make the fuller work on my truck, t-case low range is only a bandaid, and it's a pain to stop, re-engage in highspeed and killing the clutch to start.

I really don't know if the O-S max spin is really 2500rpm, as you said, it might be a problem in some case, when you need to speed a bit on the highway.. Maybe Haulin can chime in..

Marc/

Haulin_in_Dixie

Just got back from six 250 mile runs, end to end.... tired. I never heard of the 2500 rpm limit. Not saying it is not true, just never heard of it. Many 3208 engine are set up to 3000 or more. With an od front box it would be .8 higher than the engine. Naw, .2 I guess... Maybe they have had some problems with them at the higher rpm's.

Just for an example, I paid $600 a few years ago for an RT613. I doubt that you will get any good deals on the internet, smaller junk yards or junk mid sized trucks sitting would be the cheapest way. Ask at garages that do truck work, a lot of them have old trucks sitting for parts.

Boatnik

Geez you are ambitious! Hope it works well for you. Take a look at Freightliner's FL-70. I work for the power company and they used to have lineman service trucks that were 4x4 with 5.9 CTD (6BTA). I do not know what tranny they used but the drivers liked them..