2000 Olds Bravada RPM's

n1zjd · #1 May 6th, 2018

Howdy folks,

What should my RPM's be when going 55? Sorry for such a dumb question. I feel like my Bravada is not shifting into overdrive. Cruising at 65 rpms at 2750. 70 is 3k. Perhaps I'm wrong but I dont remember the rpms being so high at cruising speed.

A quick google search says to tap the brake while at speed and the rpms should jump up a couple hundred RPMs when it comes out of overdrive. That's exactly what happens.

Just noticed this yesterday morning headed home from work that the engine seemed to be turning much faster at the same speed I normally drive.

Thanks for any help!

C&C · #2 May 6th, 2018

My '04 runs at approx. 2000 rpm at 65 mph. 4.2L I-6, 4L60E tranny with a 3.73 posi rear-end.

n1zjd · #3 May 6th, 2018

Quote:

Originally Posted by C&C

My '04 runs at approx. 2000 rpm at 65 mph. 4.2L I-6, 4L60E tranny with a 3.73 posi rear-end.

That's what I thought. For some reason my rpms are much higher now. Hmmm

AftonJay · #4 December 19th, 2018

that 04 is a completely different engine, 2750 at 65 sounds about right for the4.3 4L60E transmission in the 2000. I have a 99 and that is about where i am (when its working right, which it is not right now)

C&C · #5 December 20th, 2018

The size of the engine is almost irrelevant; the important numbers are transmission ratio, rear end ratio and if you want to calculate rpm (at speed) you need tire diameter. With the 4L60E transmission (which has a 0.696 overdrive) with the 3.73 rear axle ratio with a 28" diameter tire, you are looking at about 2000 rpm @ 65mph. It appears to me that your tranny is not going into overdrive (thus the higher rpm). Included is a link that can calculate your rpm/mph:
https://www.crawlpedia.com/rpm_gear_calculator.htm

AftonJay · #6 December 21st, 2018

I agree that the engine size is irrelevant, i was just pointing out that the newer I6 is a completely different set up than his 2000.

C&C · #7 December 22nd, 2018

Not trying to be contentious but here's my reasoning to his problem: same tranny, same rear diff ratio, (tire diameter different) but using the rpm calculator, he should be closer to 2000 rpm's than his stated 2750.

p.s. Since the original poster hasn't commented, our help may have gone unheeded in any event.

p.p.s. Thanks for the dialogue Jay (in any case).

woodyBR549 · #8 December 22nd, 2018

Guys, I do try to stick to my area of expertise, that being over in "cutlass Supreme FWD".
However, the problem being described here is very similar to 3.1's with a 4T60E. Maybe way off here but it usually ends up being the transmission. It is slipping when in overdrive, and will eventually throw the "Check Engine Light". Although the TPS and VSS can come into play here, my experience with this particular symptom ends with having the tranny rebuilt.
A well taken care of 4T60E will usually start slipping in OD at around 230K. I am willing to bet that his vehicle has high mileage and other issues as well. For comparison, I have a 95 Cutlass Supreme SL with 70,400 original miles and drives like its brand new. So, it's not the age...it's the miles.

lshlsh2 · #9 December 27th, 2018

need tire size for any idea of engine rpms, without that this is worthless.

C&C · #10 December 28th, 2018

Quote:

Originally Posted by lshlsh2

need tire size for any idea of engine rpms, without that this is worthless.

The standard tire for the Bravada (2000 model) is 235x70x15, which has a diameter of 28". This is the size I'm using for my comparisons/calculations; in order to get the rpm's the original poster is seeing would require a tire around 21" (which would be ludicrous). It is pretty apparent that his overdrive gear is not engaging, and thusly, his too high of rpm, for his speed.