What are your RPMs at 60MPH?

BLake · **Posted:** Tue May 09, 2006 10:25 am

When I enter a highway and accelerate, my engine sits right at 1900 RPM at 60MPH. If I speed up to 65, it shifts into top gear/ torque converter locks up. Slow down to 60 and the RPMs are 1700 and usually stay there. I don't know if it is TC lock up or 5th gear. I've driven it for 15 minutes at 60MPH/1900 RPM and never got it to drop to lowest speed on its own.

Do your Jeeps act the same or do I have a problem?

I've never gotten above 20 miles per gallon except for the first tank after reflash when I got 26 MPG for one tank. I'm trying to gather info for a trip to the dealer.

RFCRD · **Posted:** Tue May 09, 2006 10:55 am

BLake wrote:

When I enter a highway and accelerate, my engine sits right at 1900 RPM at 60MPH. If I speed up to 65, it shifts into top gear/ torque converter locks up. Slow down to 60 and the RPMs are 1700 and usually stay there. I don't know if it is TC lock up or 5th gear. I've driven it for 15 minutes at 60MPH/1900 RPM and never got it to drop to lowest speed on its own.

Do your Jeeps act the same or do I have a problem?

I've never gotten above 20 miles per gallon except for the first tank after reflash when I got 26 MPG for one tank. I'm trying to gather info for a trip to the dealer.

You will find this transmission doing some strange things at times:
First, it will lockout 5th gear entirely until the transmission is up to temperature (this is to protect the transmission). On mine it takes several miles on the expressway in cold weather to get the last upshift.
Second, you have 2 overdrives that are very close in ratio. 4th gear will optimize 55-60 mph, 5th will optimize above 60 mph.
Third, if you run near 60mph it is common (and annoying) to get a lot of up and down shift "hunting" as the trans can't decide on a gear. Unfortunately DC didn't give us a way to selectively lockout only 5th for urban expressway or fast rural type driving like is common on Allison products.

You will also find this is not a pull-it-down until the windows rattle type of diesel. It wants to run in the 1800-2200 RPM range.

KJbob · **Posted:** Tue May 09, 2006 11:11 am

Now that I have over 10k on mine, I'm starting to use the cruise control. Part of my daily commute is about a 25 mile stretch that is 55mph and pretty straight. I take my CRD up to around 65mph, until the tranny drops into it's final gear, back off the throttle to about 63 mph, and hit cruise control. I've been getting about 27.5 mpg (per EVIC; actual is probably about 2 mpg less). My RPM's are in the 1700-1800 range and the tranny isn't "searching".

Works for me.

jinstall · **Posted:** Tue May 09, 2006 11:23 am

Sorry I don't think I have ever driven at 60 mph in mine.

Endurance · **Posted:** Tue May 09, 2006 11:41 am

Yeah right!
Landstrasse speed limit is 60mph.....
What about Zubringer? Autobahn at times?

Daniel

oldnavy · **Posted:** Tue May 09, 2006 11:42 am

jinstall wrote:

Sorry I don't think I have ever driven at 60 mph in mine.

The guys in the US East of the Mississippi have 65 mph speed limit on interstaes and and a lot of 60 mph areas also, US highways will often be 55 to 60 mph unlike on the west side of the Mississippi, where we seldom have interstate speed below 70 even in a lot of metro areas. I will set the cruise at 68 mph in the 65 zone and the tac will read 1900 rpm's and she just pures and we get into low 30's mpg's that way.

jinstall · **Posted:** Tue May 09, 2006 11:46 am

Endurance wrote:

Yeah right!
Landstrasse speed limit is 60mph.....
What about Zubringer? Autobahn at times?

Daniel

Landstrasse is 100kph-62mph well actually it varies 80-120kph
Autobahns around here are 130-Unlimited I went to k-town and back today averaging 92 mph. Autobahn 63 to Autobahn 6. I don't care about the posted speed limits. If I get flased I get flased. It is only money.

oldnavy · **Posted:** Tue May 09, 2006 11:52 am

jinstall wrote:

Endurance wrote:

Yeah right!
Landstrasse speed limit is 60mph.....
What about Zubringer? Autobahn at times?

Daniel

Landstrasse is 100kph-62mph well actually it varies 80-120kph
Autobahns around here are 130-Unlimited I went to k-town and back today averaging 92 mph. Autobahn 63 to Autobahn 6. I don't care about the posted speed limits. If I get flased I get flased. It is only money.

And you can't take it with you. :shock:

jinstall · **Posted:** Tue May 09, 2006 12:02 pm

You can take the nice photo they send you in the mail with you. I have one from Stuttguart when I was doing 120 in a 80 and then 100 in a 50. It sucked 2 flashes in 45 seconds. Somewhere there is a photo of a guy on a bike doing a wheelie at 280 some odd kph that was caught on a spped camera. Oh and if you are faster than 300kph the cameras will not catch youin the right position.

BLake · **Posted:** Tue May 09, 2006 1:24 pm

jinstall wrote:

You can take the nice photo they send you in the mail with you. I have one from Stuttguart when I was doing 120 in a 80 and then 100 in a 50. It sucked 2 flashes in 45 seconds. Somewhere there is a photo of a guy on a bike doing a wheelie at 280 some odd kph that was caught on a spped camera. Oh and if you are faster than 300kph the cameras will not catch youin the right position.

Did they get his license plate or just a cool picture? Navman GPS with camera database. Is that available in your area? Read about them here: http://www.pocketgpsworld.com/

I have to drive 60, actually 57mph on GPS, because the cops don't have a quota, they get to write as many tickets as they want. My highway mileage stinks and trying to find the cause. I drive for 10-15 minutes in stop and go traffic to get to the highway and the engine is warmed up before I get there. I find the transmission operation strange but if everyone's does it I'm not worried. If the computer thinks the engine or tranny is cold and it really isn't, then I have a problem. About one time in 10, the tranny drops into top gear at 58-60mph. No consistency and that bothers me.

My diesel suburban is very consistent with regards to speed/load/shift points. Lack of TC lock-up is a sign that something is wrong and needs to be fixed or the tranny will burn up in short order. It's one of the things you watch for when driving.

oldnavy · **Posted:** Tue May 09, 2006 2:57 pm

Pull the IC hose off the EGR Flow Control Valve and see if it is full open, it should be open 90* to the valve body with engine off. If it is only partally open then it means it is stuck in that position and that will knock mpg's in the head. However I would think if that was the problem you would have had a CEL for a short while, CEL's turn off after some many restart on some issues and will not light up again.

RFCRD · **Posted:** Tue May 09, 2006 3:10 pm

BLake wrote:

jinstall wrote:

You can take the nice photo they send you in the mail with you. I have one from Stuttguart when I was doing 120 in a 80 and then 100 in a 50. It sucked 2 flashes in 45 seconds. Somewhere there is a photo of a guy on a bike doing a wheelie at 280 some odd kph that was caught on a spped camera. Oh and if you are faster than 300kph the cameras will not catch youin the right position.

Did they get his license plate or just a cool picture? Navman GPS with camera database. Is that available in your area? Read about them here: http://www.pocketgpsworld.com/

I have to drive 60, actually 57mph on GPS, because the cops don't have a quota, they get to write as many tickets as they want. My highway mileage stinks and trying to find the cause. I drive for 10-15 minutes in stop and go traffic to get to the highway and the engine is warmed up before I get there. I find the transmission operation strange but if everyone's does it I'm not worried. If the computer thinks the engine or tranny is cold and it really isn't, then I have a problem. About one time in 10, the tranny drops into top gear at 58-60mph. No consistency and that bothers me.

My diesel suburban is very consistent with regards to speed/load/shift points. Lack of TC lock-up is a sign that something is wrong and needs to be fixed or the tranny will burn up in short order. It's one of the things you watch for when driving.

I sense something is off and took mine to the dealer today for some of the same irratic highway shifting issues. Unable to predict or even duplicate. Usually happens when trans is hot (run @45 min on highway). Often upshifts (@ 60 mph) from 4th to 5th with a "thump", especially if I'm not able to accelerate through the upshift. Notice it also in lower gears too but not as often. This didn't happen before the reflash.

BLake · **Posted:** Tue May 09, 2006 5:01 pm

oldnavy wrote:

Pull the IC hose off the EGR Flow Control Valve and see if it is full open, it should be open 90* to the valve body with engine off. If it is only partally open then it means it is stuck in that position and that will knock mpg's in the head. However I would think if that was the problem you would have had a CEL for a short while, CEL's turn off after some many restart on some issues and will not light up again.

I need a diagram or a picture. Are you talking about the hose as it goes into the intake manifold? I'm not dumb about engines but this one has a lot of hoses and wires and stuff going everywhere. It will take me awhile to figure things out. Alldatadiy doesn't have this model available yet.

Hurry up with your breather, my tubes are coated with oil and I want to nip in the bud.

oldnavy · **Posted:** Tue May 09, 2006 5:56 pm

BLake wrote:

Hurry up with your breather, my tubes are coated with oil and I want to nip in the bud.

Mine are two. :shock:

Ok, the large hose from top of radiator on drivers side and it goes down to where the EGR FCV is located on driver side of the engine. The valve closes when the engine is turned off and after a short delay and engine is stopped it returns to full open position. Igt is in a metal tube section of the device and when full open the edge of the flap or valve will be facing toward the hose and if it is only half open will cut the airflow down. This thing works just like flue damper in a chimmy, turn it 90 degrees one direction and it is closed and turn it 90 degrees the other way and it is full open. If turned 45 degrees it is then half close or 1/2 open restricting the airflow in the stove. Has this helped or do I need to see if I can find it in the service manual and copy it to here?

BLake · **Posted:** Tue May 09, 2006 6:35 pm

Thanks, oldnavy. I think I saw that part. I don't know the proper name of the thing. Must get a manual.

oldnavy · **Posted:** Tue May 09, 2006 6:53 pm

BLake wrote:

Thanks, oldnavy. I think I saw that part. I don't know the proper name of the thing. Must get a manual.

Jeep call it the EGR Flow Control Valve.

spencevans · **Posted:** Tue May 09, 2006 7:22 pm

I have a lift and run bigger tires but I consider that to be an advantage on the CRD. Lift's don't adversely effect fuel milage on a diesel like a gasser because the diesel has the low end torque to crank the larger tires.

If I take my CRD up to 57mph it will shift into 5th gear and then drop to about 1700rpm. I then can lower my speed to about 54-55mph and coast on the highway at 1600rpm's with out having the tranny hunt for gears. By doing this I expect to get over 30 mpg. At 60 mph I ride at about 1800 rpm's with the lift and bigger tires. (245/75/16)

jinstall · **Posted:** Wed May 10, 2006 7:50 am

Depending on the grade mine shifts from 4-5th at WOT around 85-90 mph. It will pull to 120 on a slight down slope.

LibertyCRD · **Posted:** Wed May 10, 2006 8:22 am

spencevans wrote:

I have a lift and run bigger tires but I consider that to be an advantage on the CRD. Lift's don't adversely effect fuel milage on a diesel like a gasser because the diesel has the low end torque to crank the larger tires.

If I take my CRD up to 57mph it will shift into 5th gear and then drop to about 1700rpm. I then can lower my speed to about 54-55mph and coast on the highway at 1600rpm's with out having the tranny hunt for gears. By doing this I expect to get over 30 mpg. At 60 mph I ride at about 1800 rpm's with the lift and bigger tires. (245/75/16)

This is exactly how mine shifts too. 5th gear lockup is at 57 mph. I noticed the other day that my Jeep will turn lower RPMs at 59 than it does at 54 because of this. So theoretically at 60 you'd get better mileage than you would at 55. Another reason to learn the oddities of the vehicle you drive...

CATCRD · **Posted:** Sat May 13, 2006 6:14 pm

Mine shifts into 5th at 57 and settles at 60mph at just under 1800 rpm, maybe 1750.

What are your RPMs at 60MPH?

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