Trucks running high rpms...

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Dec 15, 2007 | 10:02 AM

Big_Man_Brad

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From: Upper Pennsula Michigan

Trucks running high rpms...

Ok Latley my truck has been running really high rpms at 55mph..Normally at 55 mph it runs at 1550-1650 rpms and yesterday on my way to work it ran at 2100rpms....It did this 2 or 3 times to me so i'm a little concerned..I have an after market tach in there since it didn't come with one and my dad and i check all the termanials and they seemed to be ok..I think my tach is reading right because i can hear the engine pitch..I have a 1996 f-250 E40d trans 460 v8 4x4 ....

Dec 15, 2007 | 10:23 AM

phoneman91

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From: Aurora,Colorado

Did the transmission go into overdrive when the RPM at 55MPH increased?? Try running the truck in third gear and see if there is a change in RPM.

Dec 15, 2007 | 10:59 AM

Big_Man_Brad

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From: Upper Pennsula Michigan

If i run it in 3rd gear the truck runs around 2300 rpms...Could this be a torque converter locking problem???

Dec 15, 2007 | 11:01 AM

SpeedRebel09

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From: Coats, North Carolina

I'm thinking overdrive problem.

Last edited by SpeedRebel09; Dec 15, 2007 at 11:03 AM. Reason: didn't read the rest of the post.

Dec 15, 2007 | 11:07 AM

Big_Man_Brad

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From: Upper Pennsula Michigan

It works i press the button down and it shifts down to third gear and than i press it again and it returns...The only thing i did different is run synthetic oil in it but i have been running it for the last 1020 miles is the quaker state 10w-30 high torque...

Dec 15, 2007 | 11:34 AM

rikard

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From: North Reading Mass

Sounds like the Torque Converter lock up might be disengaging.
regards
rikard

Dec 15, 2007 | 12:50 PM

danr1

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From: Sand Lake, MI

Check for codes, you'll probably get 627 a 628 or a 629 or all three.

Having similar problems with mine.

I'm going to run some test but I need the tranny harness from a truck at the junk yard to use as a test lead to do it but they are not open today.
I have a service manual for the E40D, it lists how to test it.

If you post the codes you get I'll post what test to do.

I replaced the solenoid pack the first time and that helped but now the problem has returned.

<u>Do not</u> pry the solenoid's electrical connector off (passenger side of tranny behind the small heat shield.), with a screw driver, you <u>will</u> damage the solenoid pack if you do.

To unplug it press the release button in the center of the connector, passenger side of connector, and take it off by hand only (remove the shield) when you check to see if the connections are clean and dry.