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Joe  Barfield
Joe Barfield, Master High-Tech
Category: Car
Satisfied Customers: 1354
Experience:  Transmission Tech - Management Master Winner 3rd place Entire US Southeast region #1 after masters
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Torque converter..overdrive..a problem when towing my boat trailer

Resolved Question:

I own a 1993 Range Rover Vogue Plus with the ZF 4HP22 automatic gearbox which is my problem. That gearbox is a 4 speed with an automatic torque converter lockup system (lets call it an overdrive) that activates at 80km/h. Fine when running light but a problem when towing my boat trailer which weighs about 1900kg. I cannot get into fourth gear on the long hills at 90km/h when I need that gear most. I have to use third gear using more petrol and reving higher with more wear. Is there some modification that I can switch the overdrive off so the gearbox stays in fourth??? The kickdown drops me into third gear above 80km/h.
My local drivetrain mechanic says the gearbox is controlled internally, so no.
Any ideas would be most welcome.

Submitted: 6 years ago.
Category: Car
Expert:  Joe Barfield replied 6 years ago.
Hello, Your guy nailed it ! You must let the transmissions internal comp......decide which gear the unit should be in. thanks joey
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