Odd High Speed Shifting in 2000 1500

Dalek_ZED · Apr 25, 2016

Hey, so I am wondering if anyone could help explain what seems to be a miraculous phenomenon. I have a 2000 Ram 1500 with a 5.2 V8. Everything is stock and pretty well taken care of except that I often push the vehicle. I was on the freeway one night trying for a top speed and at around 112 mph my RPMs dropped from about 4200 to around 2900. I have done it since with myself and multiple other people that have a decent knowledge of vehicles and no one can explain it. I can continue to accelerate and the throttle is responsive so I am not in neutral. I also counted the gear changed from stop and for all intents and purposes it seems to be shifting into 6th gear. Its not an issue of course but I am wondering if I am missing out on some mid range power because of some strange misgearing or some such. Any help appriciated.

DodgeTx · Apr 26, 2016

the 46re is a 4 speed automatic transmission, you are probably hitting overdrive.

However I do not understand the sudden drop in RPMs perhaps the computer is lying to you is it still screaming? or can you hear the rpm drop?

It could also be a governor that kicks it down once it hits 112mph.

does it slow down once you hit 112mph?

I hope you have some very good tires.

BlackMagnum2000 · Apr 27, 2016

Isn't there supposed to be a speed limiter somewhere around there? Maybe you're hitting that? Idk. Definitely a weird one. That's all I can think of

dudeman2009 · Apr 27, 2016

What your feeling is the torque converter locking up. Mine does the same thing at about 110mph. All our trucks should be speed limited to about 114mph, thats a smooth limit too, no harsh kicks, it will just refuse to accelerate more than that. I havent counted to see if it locks up at any other time, but that is what is 'shifting' at that speed. Personally I would have had it tuned to lockup at 70 for max fuel economy, but that isnt great for towing.

dapepper9 · Apr 27, 2016

Overdrive aka 4th gear

dudeman2009 · Apr 27, 2016

I stand corrected. I went back and did some math, turns out these work slightly different than heavy diesel automatics. The others are correct, it is the shift from 3rd to 4th.

In most of the automatic trucks that I worked on the torque converter would only lock once cruise was achieved. This was programmed into the computers to occur above a certain speed while under little to no acceleration. This was done on many trucks to prevent low speed bogging of the engine.

I'll have to count the number of shifts again after I get my tranny rebuilt.

dodge dude94 · Apr 27, 2016

1,2,3,4 then lock up.
You can get lock up in 3rd if you have the OD off. When I did 110 one day I was seeing around the same rpm when mine hit lock up

dudeman2009 · Apr 27, 2016

dodge dude94 said:
1,2,3,4 then lock up.
You can get lock up in 3rd if you have the OD off. When I did 110 one day I was seeing around the same rpm when mine hit lock up

I didnt know that these trucks were new enough to do that. Lockup outside of max gear is new to me, at least on anything not small. I've counted at least 6 rpm changes in my moms minivan, so I know they do it out there. Just not in ours, i'm glad I learned that, now I can stop being pissed at it.

Dalek_ZED · May 3, 2016

Thanks guys, glad nothing is wrong. The more you know.

Odd High Speed Shifting in 2000 1500

Dalek_ZED

Junior Member

DodgeTx

Senior Member

BlackMagnum2000

Senior Member

dudeman2009

Senior Member

dapepper9

Senior Member

dudeman2009

Senior Member

dodge dude94

Millennial Boomer

dudeman2009

Senior Member

Dalek_ZED

Junior Member

Similar threads

Latest posts

Staff online

Members online

Forum statistics

Share this page