RPM problems I have a 2004 DODGE RAM 3500 6 speed manual trans. the trucks RPM in 6 gear is running at 1500 RPM at 100 km/hr. It usually runs at 2000 RPM at 100 km/hr. There's 120000km only on the truck. Any ideas what this could be???

sounds like you may havea torque converter lockup issue, one way to check is while in slower traffic (15-35mph) gear down your transmission such that you are at a higher rpm (2000-2500) then take your foot all the way off the throttle, if it is in lockup your engine rpm will stay about the same, if not it will go to about idle.

If the tcc doesn't unlock while shifting it will shift very hard and if it slips it will make your temperature increase

change trans fluid and filter and a fuel filter might not hert

I am going through this now my 2000 ram 3500 always had a problem with reverse

I chocked it up to a quirk of the transmission! But my mechanic found out that they only placed this trans in late 1999 and early 2000 trucks first years the 6 speed was offered. It comes with a smaller clutch and synchronizer that are no longer available unless you find a dealer with old stock sitting on a shelf. I am having to updated my cultch and am having to replace the gears that will allow the new type synchronizer to work this in just a about ½ the price of a new transmission BOHICA/FUBAR

So just get ready for a shock if you need to replace synchronizer rings

remove trans oil pan. there you will also see your trans filter,

Check tranny fluid level

possible speed sensor at rear of transmission,does engine rpm sound higher then narmal,and is your trans shifting as it should,if these problems are also present replace the speedometer sensor at rear of trans,$50 to 60 bucks

usually it is a faulty vehicle speed sensor on these trucks. it is located in the rear axle taking a reading off of the ring gear look for a sensor with two wires in the center of the rear axle this should fix the issue

stop up fuel filter or fuel injection pump. pressure low.make sure air filter is not stopped up.diesel engine need to get air in order to run well .check the egr valve and pvc valve .make sure they are not stuck open.

bad injector?
easy to test with vom, just check from terminal on injector to ground if one reads different thats the problem, you do need to disconnect wire to check, my help is free and will be glad to help further just vote fixa..LOL my rating is all I care about. Hope yu can help me too.

have you had the vehicle speed control reprogrammed if not that could be your problem