Engine/Transmission (1998.5 - 2002) Drivable issue rpm surge at 40mph

[dom0621]

I have 2002 2500quad cab 4x4 71000miles. At 40mph gone up hill the rpm surge up from approx. 1000 to 1500. Anybody else with the same problem?

 

[rainfly]

Hey dom, It would help to know more about your truck. What kind of transmission? Any add-ons? Anything changed from stock?

 

[dom0621]

Automatic Trans and no add-on. I have a Super chip in high perform mode. But it does it in stock mode also.

 

[rainfly]

Well, mine does the same thing. The transmission kicks out of overdrive to climb a hill. It downshifts into the next lower gear (3rd), and the rpms go up. Sounds like that might be what yours is doing? Nothing to worry about.



If you get onto some steeper hill-climbing, the transmission will automatically kick down into 2nd gear, and maybe even down into 1st gear for the really awesome climbs. Each time, engine rpms will jump up from 1100 to about 1500. That keeps the engine from spinning too slow, called "lugging". Lugging down is hard on engine bearings and cylinder cooling because at low rpms the oil pump spins slow and the cooling fan spins slow at the same moment you are asking the truck to do some extra work (climb a hill).



Raising the rpms increases your engine oil pressure (protects the bearing surfaces) and shoots more coolant through the engine (takes away the extra heat caused by hill-climbing). Your transmission knows to do this automatically, to save the engine from melt-down.



If you've ever hiked up a steep hill, you'll remember your heart had to beat faster. Your heart's higher rpms increased your "oil" pressure, and more "oil" flow took away excess heat generated by your muscles to your skin (your radiator). Nothing to worry about.

Good luck.

 

[steved]

If it is the TC locking/unlocking on its own without provocation... that is a common issue with these trucks and there are a couple "fixes" on the board... just need to search.

 

[rainfly]

I agree with 'steved'. I downed a second cuppa' joe. Finally realized the key word in dom's original post was "surge". I completely missed it the first time. If dom is having problems with repeated rising and falling rpms while he's climbing a hill then the torque converter lockup is the probable culprit.



John in NorAz told me to clean all the electrical contacts at the battery terminals, then tighten all the ground strap bolts on the engine. Fluctuating electrical current can cause it, he said. The problem was solved; took only a few minutes to correct.



Sorry about that earlier post. Note to myself: drink both cups of coffee before typing anything on TDR.

 

[dom0621]

What is the easiest way to search? I have not been on this site in a while.

 

[rainfly]

On the top of any TDR page click on Discussion Forums and go down to Search Forums. Enter "Key Words" like torque converter or whatever, maybe even surge. The search engine calls up a list of all discussions threads with those key words in the title. You also customize the search so it only calls threads dealing with your year and model truck.

 

[MDSlover]

my2001 has had the exact same problem that yours is havingif you hold the throttle steady on even ground between1000 and 1500 there is a light surge almost like a air leak i have had to change the ecm the pump the lift pump and injectors and it still does it so i just gave up trying to figure it out and just drive it

 

[dom0621]

I had the trans rebuilt at 46000 miles and a fass lift pump at 50K. And the problem came back at 70K. Somebody has to have a solution.