converting to an auto

[carroll7645]

Actually I'm going through a conversion process and was surfing today,and read that when you go to a high horsepower or high load application the stock PCM won't keep up. Does any body have any thoughts?

[DNRCUSTOMS]

what are you converting from, MAybe 5spd to auto??

[carroll7645]

Actually a 454 SM465 to a '94 12 valve 518. I,m a chevy guy that couldn't resist that big cummins power. I'm about half way through the conversion, when I read today on a website that when you put high horsepower to the stock PCM it wasn't good enough. Sad news for me because I have already bought a wireing harness and PCM from a dodge pickup to power to transmission. I think its a 518, but I'm not completely sure, all I really know is that it cost me an arm and an leg and I don't want to mess it up. If there is a better controller out there, I'll get it.

[Joe G.]

The stock transmission for a '94 Dodge is a 47RH. It can be controlled with switches, but that's not the problem. The stock 47RH has a really sloppy torque convertor so you have to get an aftermarket TC for it. Then you have to get a valve body to go with it. The PCM does not have a lot to do with the power that the trans can handle. You will need a TPS from a '94 or replace that function with a pot. Read this thread on another forum: TPS myth buster - TDR Roundtable. You can get a really strong trans from DTT or some other major transmission builder. Do some searches for all the transmission info you can stand.

[carroll7645]

Thanks for getting back to me Joe. The reason I think its not the 47 is that it has alot of pins on the connector, like 14 or 16. Its been a year since I bought the trans and I have forgotten all the particulares because the transmission shop said everything that could be done to a transmission was done to this one. Not a real dodge guy so I didnt pay much attention, just the bill. As far as aftermarket goes, it has it,converter ,long lever,CTM shafts, etc. He did tell me though that if I had a choice, get a PCM from a 98 model pickup. Supposed to be the best by far and that proves to be true, at least the ones on E-Bay are twice the money over any other year. The one I found was from a 96. Thought I would run it until I found a better one. I guess my concern was weather anyone has heard of transmission problems that were fixed by eliminating the factory PCM, or are people running twins and aftermarket transmissions with the stock PCM with no problems.

[Joe G.]

If a '98 PCM works it's a 47RE. The 47RH has a fly weight governor (H=hydraulic). The 47RE is almost the same transmission except that it has a electronic governor (E=Electronic). It takes more wires for the PCM to talk to the RE. The RH has a wire to go to OD and a wire to lock the TC clutch. The third wire is 12 volts. Most conversions are done with a 47RH because controlling it is more simple. The only electical control is for OD and the torque convertor clutch. Other than the governor and VB, they are the same gadget. The PCM only controls shifting, it has nothing to do with how much power the thing can stand. I sure hope that the guy who did your trans knew what he was doing, but from what you say he said I'm a bit suspicious.

[tractorpuller]

I think I might steer clear of that guy, if he is telling you a pcm controls how much power the tranny will take. I think if you are putting this in a chevy some kinda aftermarket standalone controller may be easier to hook up than trying to put a dodge harness in a chevy though. But that wont make it hold moer power.

[tractorpuller]

Originally Posted by Joe G.

The stock transmission for a '94 Dodge is a 47RH. It can be controlled with switches, but that's not the problem. The stock 47RH has a really sloppy torque convertor so you have to get an aftermarket TC for it. Then you have to get a valve body to go with it. The PCM does not have a lot to do with the power that the trans can handle. You will need a TPS from a '94 or replace that function with a pot. Read this thread on another forum: TPS myth buster - TDR Roundtable. You can get a really strong trans from DTT or some other major transmission builder. Do some searches for all the transmission info you can stand.

nonmembers cant read posts over 7 days old.

[Joe G.]

I don't know what to tell you then. That is a long thread. Too long to clip and paste here. It goes into how to modify the circuits so the TPS can be adjusted with only a pot instead of messing up the linkage. It also goes into removing the TPS from the circuit and setting the speed you want OD and lockup to happen with a pot regardless of throttle position. It has info from testing and the values of the various resistors and pots involved with modifying the circuit. Some guys are running without the TPS and are a lot happier with the way the trans works. You have to subscribe to the magazine inorder to be a member.

[dieseltracks]

Not sure what "your guy" means about the PCM not handling the power. The PCM has nothing to do with how much power anything will hold. I think you'll be fine with what you have. Some guys are clear up to 800-1000hp with these trucks and have no issues with the PCM that I'm aware of. If there is a problem, I know nothing about it. A PCM doesn't know or care if ur runnin 500hp or 50hp, it just does what it's suppose to do:thumbsup.

[carroll7645]

Where I was getting my information, or scare for that matter, was from an internet site that builds bulletproof transmissions for diesel applications. They said that they used PCS to control their transmissions. Thats where my question came from. If they are building transmissions for dodges, then you already have a PCM, If you are doing a conversion, and have to acquire a controler different story. Maybe getting a PCS controler would be better.???? I have alot of faith in the guy that built the transmission, have spent alot of money there over the years. I have since identified that I have a 47re, somewhere in the 96-2000 era. Thanks

[Joe G.]

I don't think you want the one from Dodge because it does other things than control the transmission.