Hi everyone, new here, but not new to the dodge truck. Im in need of a lil help, I did some searching, but couldnt really get a definate answer. My 1995 ram3500 diesel has been having some trouble with lockup. At around 65-70mph the truck would jump in and out of lockup. It does it more often when Im pulling a load or going up a hill. I read that its a noise pickup probem with the pcm, but I couldnt find any solution other than wraping foil around the ground wire(havent tried it yet). Ive had the tranny at the dealer 2 times already and they cant figure out the problem, Ive seen that most of the truck that had this problem happen around 1100-1400 rpm, but my truck is around 1900-2200 rpm when it happens. Please if anyone can help me out in anyway it would be appreciated.

TIA

John

 

Welcome to the forum John. Hang around, I'm sure someone will chime in who knows a little about your problem.

[sm=welcomesign.gif]

 

Thanks energizer, I hope someone can help out

 

hey John havn't had the problem in that rpm range alot but one thing to check that sounds funny is the battery cables. if theyare corroded they will cause a frequency type disruption for the pcm that causes lockup to go in and out but it usually happens in that lower range of rpm. but i would check that first. while at the dealer has anybody done a torque convertor lockup test where it tests the effectiveness of the convertor maybe it is starting to fail and this is just the early signs of its failure very possible. let me know

 

I agree with checking the cables, especially the grounds. I had the same problem and cleaning the grounds made my Ram good as new again.

Yeah I know ... weird

 

DID SOMEONE SAY 1995!!!!!!!!

Well buddy, I have a 95, 2500. I can tell you what I know could be possible causes.

Here's a quick summary of how your tc (torque converter) locks and unlocks.

Your tranny should be a 48RH (A618). It's a hydraulic transmission for the most part.

Your tc locks up when:

1. The tranny is in 3rd or 4th (overdrive)

2. The speed is above 30 mph (roughly)

3. There is sufficient accelerator pressure being applied. (Your throttle position sensor is what gauges how little or how far you have the pedal applied.)

There are a few other factors that are needed for lockup to occur. That happens in the tranny and is not a concern of mine right now. I would not worry about the kickdown/dentent rod this minute.

The things YOU can do before you take it to a shop are:

Make sure ALL battery connections are clean and tight. If there is any corrosion, that will cause erratic voltage readings in the PCM and throttle pos sensor.

Your throttle position sensor may have done it's useful time. **** breaks or only has so much life to it.lol. You can remove the TPS and clean it with electrical component cleaner. Some guys even drill the plastic housing to soak the insides. It works, and it works well. Just make sure to cover the hole with a sealant. Somewhere on this site is a DIY on the subject. Someone will point you there or you can do a search.

Make sure all the electrical connections on the tranny are clean and tight as well. You can split all the wire harness connectors and spray them as well. Then apply dielectric grease when you plug them back in.

Another cause of rapidtc lock/unlock is a bad or misaligned brake light switch. The switch has a **** setup under the dash. A teltale sign of a bad brake light switch is the cruise control will disengage on its own. It's usuall from a bump in the road just big enough to make the brake pedal "jiggle" just enough where the switch activates and the cruise kicks out. Sounds far fetched but it took ME 4 months to figure it out and show the mechanic......LOL. My buddy was behind me and thought I was tapping the brake lights. Then I figured it out because I consider myself a Dodge Ram electrical system MASTER...............lol.

In my mind anyway.

So there are some things to check.

Batterys, GROUNDS, TPS, and harness plugs.

Your TPS could very well be bad. Mine has 190,000 and gets a cleaning once a year thru that little access hole I made....lol. Works like a charm.

Ok my friend, good luck with that ride.


LONG LIVE THE 95's!!!!!!!!!!

 

Well I sure am glad to see that you are back in action Demon. I saee you're still modest.



Stick around, Kev ( Baja ) is haveing a TON of problems with his 1st gen that maybe your expertise can help him out with.

 

the trans is a 47 demon-just so you know

 

You sure? All my friends 1 tons have 48RHs in them.

I could be wrong.

 

the 48's didnt show up untill 03.5 before that you had the 47RE, I believe his may be a 47RH.