JMC,

I hope you can help me. Please see my sig for truck specifics. A user told me you might be able to help. I changed from 3.55 to 4.10 gears. My tires are 29.6 inches tall versus the stock height of 30 inches. I've been to two speedo shops, one of which changed the speedo gear (supposedly) but said they made all the correction possible and told me I am within 1 mph at 70 mph by their dyno. The second tested my truck on their dyno and got my speedo reading 67 when the dyno shows 60 mph. This matches exactly the results when I check my speed to another vehicle. This shop did not have any idea of what gear to use and of course Ford dealers are no help! Do you know what speedo gear I need to buy and where I can buy one? I sincerely appreciate any help you can give, especially part numbers or tooth count.

WarEagle

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98 F150 Lariat extended cab, Pacific Green/Silver Frost,
Grey Leather Capt chairs, AM/FM/Cass/6-cd changer,
full tint, color matched bug deflector, vent shades,
A.R.E. hard bed cover, Ultra type 50 polished wheels,
BF Goodrich 315 55R x 16 Sport Truck Radial T/As, 4.6L,
AT, Towing Package, Airaid, Superchip, JBA headers,Flowmaster dual
exhaust, Flowmaster 50 series muffler, 4.10 gears

 

x

[This message has been edited by JMC (edited 02-10-2001).]

 

WarEagle,

Fron the factory you should have had a 20 tooth gear. The speedo gear that you would need is a 22 tooth gear. Unfortunatly I do not have the part number for a 22 tooth. The closest is a 21 tooth. PART # 17271-C9OP-A, 21 teeth Purple. From the factory with your speedo showing 60 mph you would be doing 51.24 mph. If you switch to a 21 tooth it would be 57.14 mph.

Regards

Jean Marc Chartier

 

JMC and Mike.

Thanks for your help. I've ordered the 21 tooth gear. The hassle of correcting the speedometer has been bad but the performance gained by the gear change is worth it.

WarEagle

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98 F150 Lariat extended cab, Pacific Green/Silver Frost,
Grey Leather Capt chairs, AM/FM/Cass/6-cd changer,
full tint, color matched bug deflector, vent shades,
A.R.E. hard bed cover, Ultra type 50 polished wheels,
BF Goodrich 315 55R x 16 Sport Truck Radial T/As, 4.6L,
AT, Towing Package, Airaid, Superchip, JBA headers,Flowmaster dual
exhaust, Flowmaster 50 series muffler, 4.10 gears

 

Hi JMC,

Thanks for giving him a hand, I was the one who asked him to send a post to you here, to see if perhaps you might be able to tell him what reduction gear he needs. I had remembered that you had done a bit of work in this area in the past and had helped a number of other people in similar situations, so I thought that you might perhaps be able to help, and thus suggested that he contact you here.

Thanks for helping as always JMC,

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

 

Hi WarEagle,

Well, at least you're lucky in that yours is a 1998 model, the last year for the reduction gear in these F-150's.

Good luck!

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Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer