Help needed with towing capacity
Thread Starter
|
Freshman User
Joined: Nov 2004
Posts: 34
Likes: 0
Help needed with towing capacity
Hello.
I have a 1998 4x4 Ford F150 extended cab truck with a 4.6L V8. I have towed a 17' fiberglass fishing boat fine for years. I have recently started shopping for a camper. My main problem is determining the axle ratio (without tearing into the rear axle). I have checked the rear axle for any markings (such as the metal tag that usually hangs off one bolt on the chunk), but I cannot locate anything. I have also checked my paperwork and manual, but the manual shows 2 possible gear ratios for my truck. Depending on the gear ratio, the manual shows 5100# or 6600# max trailer weight.
Does anyone have an easy way to determine the gear ratio? Can I submit the VIN number to a website or the Ford Dealer, and can they determine the gear ratio?
I have a 1998 4x4 Ford F150 extended cab truck with a 4.6L V8. I have towed a 17' fiberglass fishing boat fine for years. I have recently started shopping for a camper. My main problem is determining the axle ratio (without tearing into the rear axle). I have checked the rear axle for any markings (such as the metal tag that usually hangs off one bolt on the chunk), but I cannot locate anything. I have also checked my paperwork and manual, but the manual shows 2 possible gear ratios for my truck. Depending on the gear ratio, the manual shows 5100# or 6600# max trailer weight.
Does anyone have an easy way to determine the gear ratio? Can I submit the VIN number to a website or the Ford Dealer, and can they determine the gear ratio?
Posting Guru
Joined: Nov 2000
Posts: 1,005
Likes: 1
From: Cincinnati, Ohio
The easiest way would be to get the axle code off the doorjamb, as mentioned earlier. This will work fine as long as the gears have not been changed out. You can also call any Ford dealership with the VIN number and they should be able to get the ratio from the part number for the differential.
Barring that, if you can jack the truck up off the ground (BOTH wheels) and get under it, mark the driveshaft so you can see exactly how many turns it makes, mark both tires for the same reason, turn both tires exactly one revolution and count the revolutions of the driveshaft - that will be your differential ratio. It does not matter if the tires turn at exactly the same time, just that they both make exactly one revolution.
Dave / Believer45
Barring that, if you can jack the truck up off the ground (BOTH wheels) and get under it, mark the driveshaft so you can see exactly how many turns it makes, mark both tires for the same reason, turn both tires exactly one revolution and count the revolutions of the driveshaft - that will be your differential ratio. It does not matter if the tires turn at exactly the same time, just that they both make exactly one revolution.
Dave / Believer45
Postmaster
Joined: Dec 2002
Posts: 3,959
Likes: 9
From: USA
To add one thing to what Dave said: If the truck has an open differential (not limited slip), the tires will need to make 2 revolutions for a correct reading. With a limited slip, one revolution will do it. You will know if you have a limited slip differential or not by the direction the opposite tire rotates. If both tires rotate in the same direction, it's a limited slip. If one tire rotates one way and one rotates the other way, it's an open diff.
The axle code off the VIN sticker would be the easiest way to find the ratio if no tag exists on either axle.
The axle code off the VIN sticker would be the easiest way to find the ratio if no tag exists on either axle.
Posting Guru
Joined: Nov 2000
Posts: 1,005
Likes: 1
From: Cincinnati, Ohio
SoCalDesertRider, I can't believe I forgot to note the tires have to go in the same direction. Thanks for catching that one.
I do not know what ratios were available for 1998 in the F150 so cannot guess from speed vs RPM. If you can find that out you should be able to figure out which you have without too much trouble.
Dave / Believer45
I do not know what ratios were available for 1998 in the F150 so cannot guess from speed vs RPM. If you can find that out you should be able to figure out which you have without too much trouble.
Dave / Believer45
Thread Starter
|
Freshman User
Joined: Nov 2004
Posts: 34
Likes: 0
Help needed with towing capacity
Thanks to everyone for the responses.
I checked the door tag, and the axle type was H9. I assume the 9 stands for a 9" chunk? Any idea on the gear ratio, based on the axle type?
I also checked the front axle, and I could not find a tag on the front chunk bolts.
I checked the door tag, and the axle type was H9. I assume the 9 stands for a 9" chunk? Any idea on the gear ratio, based on the axle type?
I also checked the front axle, and I could not find a tag on the front chunk bolts.
Last edited by cstrack; Nov 20, 2004 at 10:28 AM.
Trending Topics
Postmaster
Joined: Dec 2002
Posts: 3,959
Likes: 9
From: USA
The H9 code is a 3.55 ratio with a limited slip rear diff. Your '98 F150 doesn't have a 9" Ford axle (last used around 1984/85). It should have either a Ford 8.8" or Ford 9.75" axle in the rear. Not sure on the front. '80-'96 F150 4x4's used Dana 44 TTB front axles.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Thread
Thread Starter
Forum
Replies
Last Post
tractormanbill
1948 - 1956 F1, F100 & Larger F-Series Trucks
22
Oct 2, 2014 02:29 PM
SoCalAngler
1987 - 1996 F150 & Larger F-Series Trucks
3
Mar 21, 2014 08:46 AM
