Ford F-250: Why Does My Transmission Shudder?

A truck that shudders will feel like it's occassionally driving over a cattle guard or a rumble strip for no reason. This is frequently the cause of friction elements slipping and gripping again. That means your F-250 might just need new transmission fluid, or it might need new clutches. Learn how to tell here.

By Pizzaman711 - October 14, 2014

This article applies to the Ford Super Duty (2004-2014).

There're a number of reasons the transmission of your F-250 might shudder. Some might be easy fixes, others could be very costly. Any time your transmission starts to feel or act different, you should diagnose the problem right away. Otherwise you could go from a potentially simple fix (like adding more transmission fluid) to the worst case scenario (buying a new transmission) before you know it.

Tools Needed

  • 1-2 Transmission Pressure Gauges
  • Socket set/wrenches to remove pressure port plugs
  • Code reader

Step 1 - Pull DTC codes

Your truck's computer is there to help you. An OBD-II code reader you can pull any trouble codes your truck's computer might have logged. This should always be your first step when dealing with an new issue, as it will help you pinpoint where your truck's problems are. Even if your check engine light (CEL) isn't on, your computer may have already logged the code and is currently going through its learning process trying to correct it before alerting you.

  1. Connect your code reader to your OBD-II port (usually located under the dash on the driver side)
  2. Scan for codes, record any codes found
  3. Research the codes

DTC codes will vary depending on your transmission, and engine, and possibly even your trucks model year. I always recommend trying to Google search for the code first. Chances are you're not the first one with a problem, and someone else on the internet has had the same issue. Worst case scenario? Call your local dealership as they'll have the information on what the code means.

Figure 1. DTC Code Reader

Pro Tip

If you don't have a code reader, don't fret. Your local auto parts store will normally pull the codes for you for free.

Step 2 - Check transmission fluid level

In addition to always pulling the DTC codes, you should always check the fluid level. A truck that's low on transmission fluid wiill exhibit problems that might not throw codes. To check the fluid level correctly, you'll need to have the truck fully warmed up. To do this, drive until the engine is warmed up. Then drive about two more miles to be sure the transmission is at operating temp. Then check your fluid.

  • F-150 transmission fluid dipstick diagram (warm)
    Figure 2. Your transmission fluid should be in this range when warm (approx 150°F to 170°F)
  • F-150 Transmission Fluid Dipstick Diagram
    Figure 3. Your transmission fluid should be in this range when cold.

If the fluid is low, you'll need to top it off with the proper type of fluid. You also need to be on the lookout for a leak. Transmission fluid doesn't really "burn off" like engine coolant does. This makes finding leaks easy, as you only have to keep an eye out for red fluid when examining your truck's underside.

New transmission fluid is a deep, but clear, red color—like a Kool-Aid. it'll have a sweet smell too. If your fluid is dark, brown, or burnt smelling, you'll need to have the fluid changed. Over time, the heat and movement of the transmission will break your fluid down. The more heavy hauling and towing you do, the quicker it will degrade. If your transmission fluid is foamy and thick, then water or engine coolant has contaminated it. This will require you to rebuild the transmission and, probably, replace the radiator. Occasionally a hole in the radiator might form on the internal barrier between the transmission fluid section and the engine coolant section. It's uncommon, but it does happen.

Figure 4. Transmission Fluid Color Comparison

Pro Tip

If you have had the fluid replaced in the past or have added fluid, you should double check that the correct fluid was used. Improper fluid will cause the torque converter to shudder as well, normally once the transmission is warm.

Step 3 - Check pinion angle

If the angle of the rear differential and the drive shaft are too far out of spec, you will get a shuddering from your driveline. This will be somewhat hard to check as it varies with both how you drive, your trucks suspension, and if you're towing or hauling. However there are some ways to help check if this is the cause of your problem.

Installing lift kits and lowering kits will change the angle of your driveshaft in relation to your rear differential. Too much difference, and the angle will cause shuddering in your drive line. Most lift kits come with shims to offset this issue.

If the problem only occurs when you're towing/hauling, the weight may be causing the angle to be too extreme. You can test by taking about 200 or so pounds off and seeing if it goes away. This can be fixed by not carrying as much weight. If that's not an option, you could also invest in air bags, helper springs, etc.

The torque may be causing the pinion angle to shift too much under hard acceleration. We call this phenomena "axle-wrap." This can be corrected with something like a set of ladder/traction bars.

Pro Tip

If you think the pinion angle may be the problem, your local driveshaft shop should definitely be able to confirm whether it is or isn't.

Step 4 - Perform a line pressure test

The specified pressure range for each transmission will vary depending on your transmission as well as the gear position. However, charts can normally be found online or in manuals like Haynes or Chilton. You'll find multiple ports for testing the pressure of internal elements on the transmission casing.

Transmission fluid pressure that is too high usually means there's a clogged line or port in the transmission. Pressure that's too low indicates a leak, or low fluid levels. If either of these are the case, the transmission will most likely need to be rebuilt.

(Related Article: How to Test Transmission Line Pressure - Ford-Trucks.com)

Figure 5. Transmission Fluid Pressure Gauge

Featured Video

F-150 with Shuddering Transmission

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