E4OD Hanging on to gear too long

[Mikes91]

Any ideas why my E4OD would suddently have begun hanging onto gears longer than normal before upshifting?

Usually she'll shift at 2000RPM under light throttle. Now she's up to 2300+. Usually shifts into OD at 38mph (indicated). Now she does it at about 42.

This is a BTS rebuild. Can't afford trans troubles now... hoping this is something simple.

If it helps, I was working on the hood cowling last weekend and did unbolt the cruise control stuff in the process to give me access to the trans computer. Connections on the computer seemed fine when I reinstalled it.

Thanks,
Mike

 

[Mike]

I'd give Brian a call right away, this is one of the first problems I've heard with his transmissions. Sounds like it is related to the underhood work you did though.

 

[towcat]

check your voltage settings on your FIPL. I have a case of CRS or I would have posted the min/max volts.

 

[argve]

Mike, check your FIPL set it to 0.95~1.2 volts. Remember do this setting with either the engine at normal operating temps or unhook the high idle solenoid. The reason for this is you don't want the high idle solenoid pushing the throttle off it's warm idle stop when doing the setting. It can be done bone cold just have to unhook the wire on the passengers side of the injection pump.

 

[Mikes91]

Originally posted by argve
Mike, check your FIPL set it to 0.95~1.2 volts. Remember do this setting with either the engine at normal operating temps or unhook the high idle solenoid. The reason for this is you don't want the high idle solenoid pushing the throttle off it's warm idle stop when doing the setting. It can be done bone cold just have to unhook the wire on the passengers side of the injection pump.

Thanks for your replies, fellows.

Here's a twist...

Once the truck is warm, things shift as normal. Would cold fluid change things? Our temps this morning were in the 40s... hardly cold. The trans still held gears after I got to school... 6 miles and a brief (3 mile) highway run later.

Driving back this afternoon, things did fine after I ran her for a few minutes.

Still sounds like a FIPL?

Mike

 

[argve]

Well could be that the TOT sensor (Trans Oil Temp) is reading the coolness and is adjusting the shift pattern to generate more heat. If you have ever noticed in the past it will hold off the shift a little longer while also not locking in the torque converter during the first few minutes of the drive. It does this in order to the transmission up to normal operating temps a little quicker - Enterprise did this the entire time I owned her. Was kind of a pain when it's below zero out and your blasting down the highway at 75mph with the TC slipping away...

Did not realize that you were only seeing this during the warm up period when I originally replied.

 

[Mikes91]

No... you're right. I think the warmup period may be extended... usually really quick.

I'll drive her tomorrow and check again...

The BTS unit itself SHOULD be fine... I suspect either a bad computer connection, a broken wire in the computer harness (though I handled everything gently--should NOT be the problem) or something like that... if there's even a problem.

Though the timing is suspicious...

Where's the TOT sensor located, and how can I test it? How can I test the trans computer?

Mike

 

[argve]

Well for testing the TOT sensor I'll have to defer to Jon (Freight_Train) or Pete (Cdnsarguy) for that because I shipped my service manual out with The Enterprise, there is a chart on a page in the service manual that gives at what temp you will get said ohmic value, and it gives the operational limits of the trans. i can't remember excatly where it's at on the trans either (again no book to jog my memory) but I want to say it's on the passengers side electrical connection because that is where most of the shift pattern data is handled (because this is where the banks transcommand plugs in).

 

[turbo69]

first things first...

Check all of the wiring...

Pull the codes. Be sure to do this with the go pedal at WOT or you will set off all sorts of unecessary codes.

Click Here for DTC procedures and 2 digit code definitions.

you will be looking for codes 26, 56, or 66.

I think that the high shifting is normal. The colder it is outside, the longer it will take to heat up the tranny to normal operating temps...

If you need the procedure, I'll type it out, but hopefully somepne with a scanner or CD will come along.

 

[Mikes91]

Thanks, guys. I'll need a scanner... are they available at auto parts stores... and does the diesel engine require a special trans scanner?

Thanks,
Mike

 

[turbo69]

MIKE-

Did you read the DTC code link at the diesel files?

· Verify that the vehicle has been properly prepared.

· Start engine and run until it reaches operating temperature.

· Turn engine off and wait 10 seconds.

· Activate Self-Test.

. . Analog VOM: Jumper STI to SIG RTN at the DLC and STI connectors.

. . Malfunction Indicator Lamp (MIL): Jumper STI to SIG RTN at the DLC and STI connectors. DTCs will be flashed on the Malfunction Indicator Lamp (MIL).

. . Transmission Control Indicator Lamp (TCIL) 7.3L Diesel only: Jumper STI to SIG RTN at the DLC and STI connectors. Service Codes will be flashed on the TCIL.

. . Message Center (Continental Applications Only). Refer to "Self-Test with Message Center."

· Place ignition key in the ON position.

· For 7.3L Diesel vehicles only, depress the throttle fully, and hold for the entire test.

· Record all Diagnostic Trouble Codes (DTCs) displayed.


There is no need for a scan tool. The scanner comment was for somebody to scan in the TOT diags pages of the manual.