I was out for a drive today and I was climbing a descent grade when I suddenly need get with it! Lol.. i was cruising at 65 and so I dropped to 4th and got with it! Shortly after I shifted back to fifth and went about my drive. Everything seemed normal the rest of the way home. The next time I took the car everything seemed normal until i got up to speed (55 in this case) which would normally have me cruising in 4th gear) that I noticed my rpms were up almost 1000 rpms then what I'm used to. Basically making me want to shift to 5th, which has never seemed nessecary at that speed.. any insight would be hugely appriciated! Thank you.

 

Since this your first post, let me say "welcome"!

Next - did she sound like she was revving faster, or was it just indicating higher revs on the tachometer? The 2005-20009 Mustangs have stepper motors on the gauges that can go bad, causing them to read incorrectly. My tach is all over the map now, and is usually incorrect.

What model year is your pony?

 

Thank you for the welcome!
My gt is a 2005. At first, I thought the same thing.. maybe the gauge itself was acting up (gas gauge doesn't work either) but with a little more driving I quickly realized that she was over revving! Times I would normally be cruising in 4th gear somewhere around 2000 rpms I now am finding she is up near 3000 rpms and sounded the part..

 

Only thing I can think of is clutch slipping (worn disk/weak pressure plate/oil leaked onto disk)..

 

Ok. If I was cruising along in 5th gear and suddenly dropped to 4th to get moving.. would something like that maybe cause the symptoms I described?

 

Only if the clutch was weak to begin with. People downshift and punch it all the time without problems.

 

You normally cruise at 55 in 4th gear? What RPM is that?

If you post a few speed/gear/RPM readings we can tell you if that is "normal" or not. We also need to know your rear end ratio to be precise, but without knowing I would guess it is 3.55 and that will get us in the ballpark.

I don't have any other ideas, besides the clutch might be slipping; other than someone snuk in and gave you a set of 4.10 rear gears while you weren't looking, which isn't very likely, LOL

To test if the clutch is slipping, cruise along in 4th gear at about 2,000 RPM, then floor it without downshifting; if the engine seems to rev without the car accelerating then the clutch is slipping.

 

I know I do!

I agree, may be time to have the clutch examined for issues.

 

How many miles are on your car?

 

55 in 4th gear puts me right around 2500 give or take. I just hit 100,000 a few days ago. As of today things seem to be back to normal. But it was definitely doing something funny because normally 4th gear at that speed still gave me room to work with but when it was doing whatever it was doing there was no staying in 4th at that speed. Rpms were above 3000 at cruising speed.