High RPM's?
Cargo Master
Joined: Apr 2009
Posts: 3,038
Likes: 4
From: South west Idaho
An easy way to check your speedometer and odometer on the freeway is with a stop watch if you don't have a GPS or any other device to do it with. If traffic is light so you can keep a constant speed for about 3 miles or more do it this way. Get it up to where you speedometer is showing 60mph, then at the first mile marker post along side the roadway start the stop watch. Time it between the mile post, 60 mph is 1 mile in 60 seconds . In other words get it to the speed it takes to hit each mile post every 60 seconds and then look at the speedometer to see if it's showing 60mph or is it on 50mph or 70 mph, then you know how much it is off. You can at the same time see if your odometer is rolling over 1 mile each time it passes a mile post. Old school way of doing it but it works and you don't have to strain your brain doing a lot of math. 
Moderator
Joined: Jul 2011
Posts: 6,506
Likes: 655
From: Sioux Falls Area
3600/time in seconds = speed in MPH
(edit ... use 3600 for one mile, so if you time 3 miles you need to multiply by 3)
mile markers are very accurate. I've measured them at work, and very seldom are they off far enough that they would throw your reading off by even 1 MPH.
i'm betting it is stuck in 2nd ....
(edit ... use 3600 for one mile, so if you time 3 miles you need to multiply by 3)
mile markers are very accurate. I've measured them at work, and very seldom are they off far enough that they would throw your reading off by even 1 MPH.
i'm betting it is stuck in 2nd ....
Last edited by meborder; Mar 30, 2013 at 09:35 AM. Reason: clarity
Thread Starter
|
Fleet Mechanic
Joined: Jun 2011
Posts: 1,804
Likes: 5
From: Southern California
Whats the modulator look like?
Thread Starter
|
Fleet Mechanic
Joined: Jun 2011
Posts: 1,804
Likes: 5
From: Southern California
Ok found it. And well when i pulled the rubber hose off nothing dripped out. But it kinda looks like inside the hose might be damp? If i replace it will fluid come spilling out?
Thread Starter
|
Fleet Mechanic
Joined: Jun 2011
Posts: 1,804
Likes: 5
From: Southern California
Can someone tell me what stock tire size was on a 74 highboy? Then i can do the equation to see what gear thing i need for the speedo.
EDIT: Im starting to think the mechanic counted the teeth wrong.....
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
Lead Driver
Joined: Nov 2006
Posts: 5,217
Likes: 506
From: Pa.
Just went for a test run. It goes into 3rd...... But what i did notice is there isnt much was a decline in RPMs when it does shift. Maybe 500 rpm drop when it shifts? I couldnt pay alot of attention to the tach cuz i didnt wana run anyone over in the neighborhood haha. But for a fact it does go into 3rd. So im thinking the mechanic counted teeth wrong when he was looking at the rear end or the previous owner had the tranny rebuilt and someone changed out the gearing in it.... Or the less likely but possibility that im going way fast then i think when i dont have the gps in the car.
Can someone tell me what stock tire size was on a 74 highboy? Then i can do the equation to see what gear thing i need for the speedo.
EDIT: Im starting to think the mechanic counted the teeth wrong.....
Can someone tell me what stock tire size was on a 74 highboy? Then i can do the equation to see what gear thing i need for the speedo.
EDIT: Im starting to think the mechanic counted the teeth wrong.....
https://www.ford-trucks.com/forums/9...ml#post9393390
Cargo Master
Joined: Oct 2010
Posts: 3,417
Likes: 32
Since your are shifting into 3rd. 10 bucks says you have 4:10 in the rear and not 3:73. I would pull alot higher rpms in mine when I had 4:10's in the rear. Time to pull the cover and read the build stamp in your ring gear or count the teeth.
Thread Starter
|
Fleet Mechanic
Joined: Jun 2011
Posts: 1,804
Likes: 5
From: Southern California
Whats odd is that when i bought the truck the PO put a 78 f250 front end HP D44 on and never checked the gear ratio. So i had the mechanic check the the front and rear gearing. He came back with 373 for the rear and 410 for the front. So what are the odds he did the rear wrong when he was counting teeth i assume?
Lead Driver
Joined: Nov 2006
Posts: 5,217
Likes: 506
From: Pa.
Have you ever had the truck in 4wd ? if so you would have tore up the drive train if the gear ratios were anything but a match .. You report that you have a 1974 Highboy .. Then the rear axle is a 4:10 gear ratio unless it has been changed
Thread
Thread Starter
Forum
Replies
Last Post
wifes65
Clutch, Transmission, Differential, Axle & Transfer Case
2
Jul 24, 2008 02:43 PM
6T6Shorty
Clutch, Transmission, Differential, Axle & Transfer Case
5
Mar 17, 2007 11:22 PM
Renegade361
Pre-Power Stroke Diesel (7.3L IDI & 6.9L)
13
May 26, 2006 01:39 PM
superman64011
1948 - 1956 F1, F100 & Larger F-Series Trucks
8
Apr 1, 2005 01:27 AM
moose94
Clutch, Transmission, Differential, Axle & Transfer Case
34
Mar 7, 2004 10:41 PM