Ok guys, I'm currently looking at an older Dodge Ram, it's a regular cab, great looking work truck. The Originaly 4 speed overdrive has been replaced due to it going out. The guy put a 3 speed in it. Now, i'm curious, aside from poor gas mileage, will this hold up? He mentioned leaving the OD off as not to cause an issue with torque converter or the computer or something? Is this a safe swap and what can I look out for. I'm not really wanting to have to leave the OD switch off especially in the event that that little button stops working and the truck can't runs safely. The 3 speed is a non OD, older unit. thanks in advance.

 

O/D off button just disables O/D. It isn't really a 'switch', it just sends a momentary signal to the PCM, to tell it to turn off O/D, and the PCM turns on the light in the switch, to let you know it got a clue. If the button stops working, the PCM will just whine about not seeing an RPM drop when it commands O/D. (mainly because, there won't be one..... ) Does the current trans have a locking converter? If not, PCM will whine about that too.

These trucks don't get stellar gas mileage to begin with, so, any freeway cruising you do is going to EAT gas. It really isn't that difficult to find the correct trans for the truck...... The extra gear makes freeway cruising far more pleasant.

 

Yes, i understand that it disables OD. Meaning, you push the button and it prevents OD from coming on. That is the reason that the previous owner says he does this because apparently it could potentionally cause and issue with the torque converter or something? If i don't push the button and OD is on, meaning the light is off and i'm running this 3 speed trans would I have to worry about anything?

I'm not going to be getting a transmission for this pickup, i'm buying it to use as a lawn care truck, to pull a small trailer and go around town, it is clean and if solid I want to make the purchase for it as I know it can hold up well doing what i need it to do. Since they don't get steller gas mileage to begin with, the likely won't be that much worse on the highway....say 13 instead of 15 lol.

let me be clear about my concern. If the button stops working, that means i cannot manually disable OD, correct? So, will something go bad with the torque converter trying to lock into OD on the 3 speed trans? I believe the current trans does have a locking converter, this is what i was worried about.

 

I think, under *normal* circumstances, the PCM hits TCC first, and the O/D. So, if the button fails, the PCM will just whine about it, and nothing bad will really happen. (everything else will still work as it should.)

Even so, I think there is a write-up somewhere around here, to install a relay, and a bit of wiring, so the PCM will DEFAULT to O/D off, and you don't have to push the button everytime you start the truck. It just sends the signal via relay, instead of the switch, and that's all the PCM really cares about anyway.

For just an around town/pull the trailer truck, I think it'll be fine.

 

I would run (not walk) away from this truck. I've seen way too many cases like this where swaps were doing half assed and sold to an unsuspecting buyer. It sounds like it's rigged together from the description. What else is going to also been halfway done on the truck? It's very easy to get trapped into a money pit buying something like this, not to mention it will likely be extremely hard to sell. It's not like there is any shortage of 2nd gen Rams out there. I'd look for another one.

I also think your 13mpg is closer to what these get with OD. You're likely looking at significantly less with a 3 speed, but it doesn't sound like you'll be doing much highway driving, so that isn't a big concern.

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Yikes, well the transmission was just put in a few weeks back. I know the fact that they went with a 3 speed doesn't seem right unless they were pulling more? You're right it would be hard to sell. I would have about 1000 in this since i'd be trading an atv for it. I currently have 1 truck but want to add another. If this isn't worth the hassle I may just stick with something a little nicer then. I mean if it runs good and drives good, it's a work truck in my opinion, and that's what I"m going for. Just figured it would be worth asking you guys about as far as the 3 speed goes and having the OD. I agree it does sound rigged, but maybe a guy had a good 3 speed that he knew he could put in it as opposed to buying a rebuilt or new tranny? So if 13mpg is significantly too much, are you saying it would be less than 10mpg with the 3 speed on the highway at 60mph?

 

My question is why would go through modding the trans mount and getting another drive shaft to fit rather then just fix or replace the trans that was in there.

 

my guess would be they had a built or at least working 727 laying around and the knowledge/tools to make it fit and work. other than cruise rpm's being high on the freeway and suck mileage i don't see any problems. it's just mechanical linkage and maybe a vacuum line. i would make sure the driveshaft is long enough by looking hard at the tailhousing. ask if you can pull it to check the length. you can tell pretty easy if theres enough shaft, end of it should go in the tranny about half way when it's bolted up. if it's just grabbing the tip theres a problem. lol

 

That's another sign to run away imo. You wouldn't put all of that work into a truck just to trade it for an ATV. I've seen way too many vehicles for sale with a recent motor swap, recent rebuild, etc. that are for sale right afterwards. Usually it means something went wrong and they can't get it to work correctly so they are trying to dump it off on someone else. In the few cases that I've seen people fix stuff like this to sell it, they cut every corner possible to make it just run long enough to sell it. You wouldn't put all of that work into doing a job like this the correct way to just get rid of it a week later. If the rest of the truck is mint and you can use the parts off it, it may be worth this. If not, I'd skip it.
I do have 33"s with 4:10 gears, but I get right around 12 mpg (occasionally 12.5 mpg) when traveling on the highway. I write down every time I put gas in it, so I check it often. This is with overdrive. I can't imagine that it would do anywhere close to that with it stuck in a 3rd gear, but since I've never drive it I can't really tell you what kind of mileage it will get.

 

Your mileage is that bad???? I can do 11 or so around town with my V-10...... That seems really low. On my 96 2500 with the 5.9, I could pull 17mpg on the freeway without any trouble at all. (265/75/16's and 3.55 gears.)