heavy shift after reaching higher speed

[blkwlf]

Have a 95 bronco, after reaching an undetermined speed over 50 mph, the transmission will start to shift hard. drives fine and smooth over that speed until it needs to shift up or down. up shifts are harder than down shifts The computer shows no codes and after reset, shifts normal until that unknown speed is reached again.

have replaced egr, map, tps, vacuum solenoid,etc etc

Is it possible that the speedometer could be the problem, sending false information to computer above a certain speed causing the heavy shifts?

 

[bidibronco]

Speed sensor in the rear end... My Bronco did that but it was from 1st to 2nd... replace the whole rear end (different story though) and put in a new sensor and the shifts got SMOOTH!

 

[miesk5]

yo; when codes were checked, was both KOEO and KOER tests done?

A technician that is unfamiliar with the EEC Self-Test can mistakenly believe that continuous Memory codes are not present when they really are. He may run KOER Self-Test and get a pass code (111) and not realize that KOEO Self-Test must be run to receive any Continuous Memory codes. He may run KOEO Self-Test while counting MIL flashes and misinterpret the repeated hard fault pass code (111) to mean that Continuous Memory does not contain any codes.

Source: by Ford via miesk5

 

[blkwlf]

thank you for that. i check all mine own codes and always do a KOEO with no codes first before doing the KOER tests.

Changing the speed sensor seemed to fix the problem, although FORD identifies the speed sensor for the ABS system only. Thats why i like this group, you can learn things Ford doesn't want you to know.

 

[blkwlf]

changed the sensor today, took it on the freeway up past 80mph. everything shifted as normal after returning to city speeds.. couldn't even tell unless your were waiting for the shift or looking at the Tach. Much smoother even in city traffic too. thank you.