high rpms while cruising

[puty72]

I remember posting this a few months back but didnt get any positive feedback. I have a 1989 ranger 4x4 2.9 with a4ld transmission. while cruising down the highway at 55 my truck runs at 3,000 to 3,500 rpms. My tach is correct because i hooked up an aftermarket one and it reads the same. I have replaced all these parts within the past year, fuel pump, filter, air filter, plugs, wires, distributor cap and rotor, ignition control module, o2 sensor, and iac sensor. Took it to the garage today and have codes ran...only one that showed up was for my stock temp gauge that i disconnected because it didnt work. I was wondering if it could be the modulator on the transmisson because the tranny fluid is good level and color and it shifts smooth for having 112k miles.

 

[IMenriched]

I remember posting this a few months back but didnt get any positive feedback. I have a 1989 ranger 4x4 2.9 with a4ld transmission. while cruising down the highway at 55 my truck runs at 3,000 to 3,500 rpms. My tach is correct because i hooked up an aftermarket one and it reads the same. I have replaced all these parts within the past year, fuel pump, filter, air filter, plugs, wires, distributor cap and rotor, ignition control module, o2 sensor, and iac sensor. Took it to the garage today and have codes ran...only one that showed up was for my stock temp gauge that i disconnected because it didnt work. I was wondering if it could be the modulator on the transmisson because the tranny fluid is good level and color and it shifts smooth for having 112k miles.

yeah might be the shift modulator.....also could be the torque converter.

IS the tack reading greater than say 2500 RPM going down the road??

or does it just "sound like" the RPMs are going high??

 

[puty72]

its reading above 2500 and also u can tell its reving high by the sound too. it makes it sluggish accelerating on hills.

 

[Big Jim M]

First things first.. swap out the filter. Filters cause lots and lots of problems.. One of which is reving engine at highway speeds.
Big JIm

 

[puty72]

alright ill put that on my list of things to do

 

[low_five]

are you sure about what rear-end gears you are running?

 

[low_five]

also, are you running smaller tires than usual?

 

[Epixstar]

My 89 does the same thing. When you mean filter your talking about the trans filter right? I dont mean to jack your threat but mine is crusing at 3000 at 70 is that still too high. Stock truck 88 on the motor 5 on the trans.

 

[puty72]

mine truck has a a4ld automatic and 4.10 gears if its normal to be runnin that high then im alright with it if not i want to try fixing it. im also running stock tires size same as printed on door tag

 

[gcfishguy]

I know it's not the same, but for reference, I have a 2008 3.0 5 speed with 4:10's.
Highway speed limit is 110km/h (68.3mph) and I'm howling along right at 3000 rpm.

Bought it a couple weeks ago. Did I think to see what gear ratio it had? No. (d'ohh)

Why would they gear it so low....? I'm in 5th gear in town a lot of the time...yeesh.

 

[Big Jim M]

hmmm

I know it's not the same, but for reference, I have a 2008 3.0 5 speed with 4:10's.
Highway speed limit is 110km/h (68.3mph) and I'm howling along right at 3000 rpm.

Bought it a couple weeks ago. Did I think to see what gear ratio it had? No. (d'ohh)

Why would they gear it so low....? I'm in 5th gear in town a lot of the time...yeesh.

Just to check to see if it has the 4:10 still in it, do this. Jack up one back tire and mark it with chalk or whatever. Then mark the driveshaft. Now in neutral, spin the tire, by hand, one complete turn.. EXACTLY.. while counting the turns of the driveshaft. There you will see what your gear ratio really is. The driveshaft will turn exactly 4.10 times to one complete turn of the tire. Or whatever you really have in there.
Big Jim

 

[Big Jim M]

Well puty

mine truck has a a4ld automatic and 4.10 gears if its normal to be runnin that high then im alright with it if not i want to try fixing it. im also running stock tires size same as printed on door tag

If the rpm is the same everytime at 65mph over and over then all is Ok. But in your first post you wrote 3000 or 3500 rpm.. If there is a difference at the same speed then you have a problem. However if it is the same everytime then prolly no problem.
Big Jim

 

[gcfishguy]

Just to check to see if it has the 4:10 still in it, do this.

Not sure if you misread, but I wasn't asking what I had in it.

Under 3 years old, 31,000miles. No reason to think the gearset was ever changed out. According to the diff tag, I have an open 8.8 with 4:10's. the high revs on the highway and being able to putt around town in 5th gear enforces that. New to Rangers but just wondering why they would gear a sport to turn 3000rpm on the highway...

It's all good! Once I hook the speedboat on behind it, it should pull like it's not even there. (just a little 14.5')
<><

 

[gcfishguy]

Still not real familiar with the Rangers...but...you said there's a stored code for your temp gauge? (Which you unhooked)

Just tossing it out there, but depending on how the temp sensors are set up, the ECM may not allow it to shift into OD until it has reached the proper operating temperature.

I will say up front that I don't know if the ranger uses one sending unit for the gauge and one for the ECM, or if they share one, and the ECM is seeing the wrong temperature, that might affect shifting into OD and cause the torque convertor clutch to slip when it should be locked....

Again, sorry if I'm way off, but something to think about for a second at least.

Carry on...!

 

[Big Jim M]

My point was

Not sure if you misread, but I wasn't asking what I had in it.

Under 3 years old, 31,000miles. No reason to think the gearset was ever changed out. According to the diff tag, I have an open 8.8 with 4:10's. the high revs on the highway and being able to putt around town in 5th gear enforces that. New to Rangers but just wondering why they would gear a sport to turn 3000rpm on the highway...

It's all good! Once I hook the speedboat on behind it, it should pull like it's not even there. (just a little 14.5')
<><

That three grand is a bit too high for a 4:10 gearing. I think I would check just to make sure the first owner didn't swap for a 4:88 or whatever.
Big JIm