Hey all,

I scheduled my regular oil change appointment and 2 days before I took it in the check engine light came on.

This is a 2004 Dodge Ram 1500 Hemi

Took it in for an oil change today and asked them to check what the checkk engine light was on for. Everyone's worst nightmare, TRANSMISSION!

The codes were P0 700 (apparently that code showed up twice, and P0 846.

They suggested that they put an additive in the ATF, that I drive for 500km, then come in and get a ATF and filter change.

This I am VERY leery about, as I have always heard, "Don't change the ATF if it has never been done...you'll blow your tranny." (People might debate on this issue, but I came across this article that seemed to make sense http://articles.chicagotribune.com/2...-atf-oxidation

I don't think the guy before me ever did an ATF, and I bought the truck with 160,000 KM. It now has 230,000 km (5 years later) and still has not had an ATF and filter change.

After searching on line I have found that the P0 846 can mean a few things including: 2/4 Pressure Switch harness is open or shorted; 2/4 Pressure Switch circuit poor electrical connection; Faulty 2/4 Pressure Switch; Internal Transmission damage; Faulty Powerterain Control Module (PCM); or Faulty Transmission Control Module (TCM) - this is all from autocodes.com

However, https://edgeproducts.com/app/uploads...cle-pdf-39.pdf only lists these possibilities for those codes: P0846 Trans Fluid Press Sens/Switch B Circ Range/Perf

In any case I am trying to figure out how to proceed.

The shop reset the computer and the check engine light is currently off (granted I only drove 3 km). Th shop suggested that if it were any other issue than needing a new tranny (like a possible electrical issue) that the check engine light would come back on as they didn't fix any electrical issue. (They also didn't fix any internal issues, but there logic seems to make sense, especially if the internal issue is at an early stage and intermittent).

What is the best way to proceed?

1) With 230,000km and never having the ATF service, would you get it changed (I really hesitate to).

2) Keep driving until/if the check engine light comes on again and take it to a Dodge Dealership and get them to use the Crysler Scan Tool (to find out exactly what the issue is)? Will the Crysler Scan Tool be able to determine what the issue is or only narrow it down?

3) Any other option?


Thanks a bunch! A rebuilt transmission is pricing out at $2,500 for parts and labor...don't want to go there if I don't have to.

 

To not change transmission fluid because it's never been done before is ridiculous. If there is a problem after the flush, then it was merely masked prior. Shops use to use pwerflushing systems and backflushing systems. Those I would not recommend. i would only use a system that lets the internal pump transfer the fluid. There are plenty of shops out there that use these.
Also, to not reset your computer after a flush can cause hard shifts..etc as the tran has learned on old fluid.

I would not put in any additives. Again, you are borrowing time. You can also cause more problems.

I would start out by the cheapest and most logical solution first. change your pan filter and your external filter and do a flush. Transmission fluid not only loses it's lubricity, but it loses it's ability to dissapate and transfer heat properly.

I made a How-to in the FAQ section. You'll take off your return line, empty the pan by starting truck and letting the internal pump drain pan fluid, take off empty pan, change filters, button back up, fill pan, drain in bucket, fill and drain again. It's very easy to do. You'll need 20qts or so of ATF+4 and a filter kit. $120 fluid change.
HERE is the HOWto

You can change as many sensors as you want if you'd like, but I'd start with simple first. If you still have problems after that, then you can re-drain the fresh fluid in a clean bucket to drain pan again. You will be able to re-use the good fluid. New rubber pan gaskets are cheap. Stay away from cork.

 

Thanks for some advice.

I'm not mechanically inclined, but have a friend who is that would help me with this
if I try this out.

A few questions:

"Also, to not reset your computer after a flush can cause hard shifts..etc as the tran has learned on old fluid." Essentially you are saying to make sure and reset the computer after? How does one do that?

In your reprocess you say to stay away additives, yet in the article you suggest that Seafoam may be useful. Isn't Seafoam an additive?

What the shop put in today was SEAFOAM TRANS TUNE TT-16.

They suggest that I drive for 500km, then come in and get a ATF and filter change. If i hear your right, you are saying also to do a flush? If so why?

They also suggest that after the ATF/filter change putting in SEAFOAM TRANS TUNE TT-16 right away...but you wouldn't automatically do that, is that right?

 

Hopefully dirtydog comes back and can provide me with some more clarification to my above questions...but I also have an update.

So I took the truck to my local non-dodge shop and they rest the computer and put in Trans Tune, you can read my original post to see about those details.

Drove it home from the shop, 2 km in distance and didn't drive it all weekend. (Took wife's vehicle to the city on the weekend and got stormed in).

So today, I drove to the grocery store. While going out, a block away from my place the check engine light came back on near a stop sign, and the truck seemed sluggish starting from the stop. I went to the gas station - 1 km from home - put in fuel as I was at 1/2 a tank before and drove away from the gas station to the grocery store without feeling sluggish. After I bought the groceries, I drove the truck home -check engine light still on - and again it was not sluggish and could reach 50 km/h and the truck seed to shift fine.

I think that I'll take it to the dodge dealership where they have an actual Crysler Scan Tool and can tell me what the actual codes are.

My local guy said the codes were P0 700 (which is a generic code) and P0 846 (which seems to list a number of possibilities).

I'll post back once I've taken it to Dodge and they tell me what the P0 846 code is referring to as it could be any of: 2/4 pressure is incorrect, or internal transmission faults exist, 2/4 pressure switch circuit is open, shorted to ground or power, 2/4 pressure switch is damaged or it has failed and/or the TCM relay power circuit to L/R switch is open (loss of B+).

What does 2/4 pressure is incorrect; 2/4 pressure switch circuit is open; or 2/4 pressure switch is damaged or it has failed mean?

 

I believe thats a code for the Governor pressure sensor. Drop the pan and replace the sensor.
As for additives, the widely agreed upon take is, ONLY atf+4 goes in your trans... I cannot speak for dirtydog, but seafoam does a make a fuel system cleaner that many people do success with. I could see him recommending that, as it does work. Trans tune is an entirely different product.

 

As soon as I drop the pan, am I also doing a transmission fluid and filter change?

If not, would you do a transmission fluid and filter change to get rid of the Trans Tune?

On all my research the P0 846 shows that it is one of the following: 2/4 pressure is incorrect, or internal transmission faults exist, 2/4 pressure switch circuit is open, shorted to ground or power, 2/4 pressure switch is damaged or it has failed and/or the TCM relay power circuit to L/R switch is open (loss of B+).

Is one of those the same as a Governor pressure sensor?


Thanks!!!

 

Look on weeds link for service manual. May help.

 

When you drop the pan, your only removing about 1/3 the total volume of ATF in your trans. Unless you get a full flush, you won't get it all out.

Yes dropping the pan will require a fluid and (might as well cause your in there) filter change.

 

What that code actually means is....
In certain gears that solenoid should he

 

See, the 2/4 solenoid should be open or closed, depending on what gear the trans is in. When the computer detects that the solenoid is open/closed when it shouldn't be, it throws a code. It could be the solenoid is bad, could be a short in the wiring etc.