Question about overdrive timing
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Senior Member
Joined: Mar 2012
Posts: 512
Likes: 1
From: Bellevue, WA
Year: 1998
Model: Cherokee
Engine: 4.0L
Question about overdrive timing
Hello, question here to experienced XJ members.
My 98 XJ seems to have a tendency to switch into overdrive rather too quickly when going uphill at highway speed (like 60 or 70mph), then gradually losing momentum at the lower revs, which forces me to quick down to regain speed. So I find myself doing this time and time again to keep my cruising speed.
My expectation, and correct me if I am wrong, is that it will stay in gear and keep at higher rev at about 2500 or 3000, until the hill is over and then release to overdrive. Or in other words, switch to OD at a later effort point.
Is there something I can modify or adjust to make the TCM delay the switching to overdrive, to correct this so it drive like a normal car does?
Thanks for any advice.
1998 XJ with 60K miles, AW4, 275/75R16 tires (32"), 4.11 gearing (D44 & D30) and speedo gear corrected (accurate).
My 98 XJ seems to have a tendency to switch into overdrive rather too quickly when going uphill at highway speed (like 60 or 70mph), then gradually losing momentum at the lower revs, which forces me to quick down to regain speed. So I find myself doing this time and time again to keep my cruising speed.
My expectation, and correct me if I am wrong, is that it will stay in gear and keep at higher rev at about 2500 or 3000, until the hill is over and then release to overdrive. Or in other words, switch to OD at a later effort point.
Is there something I can modify or adjust to make the TCM delay the switching to overdrive, to correct this so it drive like a normal car does?
Thanks for any advice.
1998 XJ with 60K miles, AW4, 275/75R16 tires (32"), 4.11 gearing (D44 & D30) and speedo gear corrected (accurate).
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From: St. Albert
Year: 1989
Model: Cherokee
Engine: 4.0L I6
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Joined: Mar 2010
Posts: 1,442
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From: NC
Year: 99 94
Model: Cherokee (XJ)
Engine: I6
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Joined: Aug 2010
Posts: 8,357
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From: Canton, MI
Year: 1999
Model: Cherokee
Engine: 4.0
Hello, question here to experienced XJ members.
My 98 XJ seems to have a tendency to switch into overdrive rather too quickly when going uphill at highway speed (like 60 or 70mph), then gradually losing momentum at the lower revs, which forces me to quick down [?] to regain speed. So I find myself doing this time and time again to keep my cruising speed.
Kind of confusing the way you are describing what happens.
What does "quick down" mean?
The transmission should kick out of overdrive when going up a hill, then downshift to a lower gear (3rd gear) if the load on the engine increases and the vehicle slows down. Then when the load on the engine decreases it will shift back into 4th gear, then lock up in overdrive when load and vehicle/transmission output speeds level out.
My expectation, and correct me if I am wrong, is that it will stay in gear and keep at higher rev at about 2500 or 3000, until the hill is over and then release to overdrive. Or in other words, switch to OD at a later effort point.
Is there something I can modify or adjust to make the TCM delay the switching to overdrive, to correct this so it drive like a normal car does?
Thanks for any advice.
1998 XJ with 60K miles, AW4, 275/75R16 tires (32"), 4.11 gearing (D44 & D30) and speedo gear corrected (accurate).
My 98 XJ seems to have a tendency to switch into overdrive rather too quickly when going uphill at highway speed (like 60 or 70mph), then gradually losing momentum at the lower revs, which forces me to quick down [?] to regain speed. So I find myself doing this time and time again to keep my cruising speed.
Kind of confusing the way you are describing what happens.
What does "quick down" mean?
The transmission should kick out of overdrive when going up a hill, then downshift to a lower gear (3rd gear) if the load on the engine increases and the vehicle slows down. Then when the load on the engine decreases it will shift back into 4th gear, then lock up in overdrive when load and vehicle/transmission output speeds level out.
My expectation, and correct me if I am wrong, is that it will stay in gear and keep at higher rev at about 2500 or 3000, until the hill is over and then release to overdrive. Or in other words, switch to OD at a later effort point.
Is there something I can modify or adjust to make the TCM delay the switching to overdrive, to correct this so it drive like a normal car does?
Thanks for any advice.
1998 XJ with 60K miles, AW4, 275/75R16 tires (32"), 4.11 gearing (D44 & D30) and speedo gear corrected (accurate).
Senior Member
Joined: Apr 2012
Posts: 578
Likes: 4
From: Ocean, New Jersey
Year: 2000
Model: Cherokee
Engine: 4.0
Next time it happens just tap lightly on the brake pedal using your left foot and it will unlock the torque convertor and gives you the extra "power" to go uphill. Try it.
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