Removing A Stripped Bolt From Transmission Pan: A Guide

Stripped bolt holes in transmission pans are a common issue, often caused by over-tightening bolts. This can lead to leaks, and the problem can be fixed in several ways. One method is to use a tap and die set to tap out the holes for larger bolts. Another approach is to use a helicoil kit, which includes a drill bit, tap, and thread putter inner. A more expensive but durable option is to use a TIME-SERT kit. For those who want to avoid drilling and tapping, simply replacing the bolts with slightly longer ones may work if there are extra threads in the bolt holes.

Using a hold-down plate

If you're dealing with a stripped bolt in your transmission pan, one possible solution is to use a hold-down plate. This method involves placing a plate between the bolts on either side of the stripped bolt, which helps to secure the pan in place. Here's a step-by-step guide on how to use a hold-down plate to fix a stripped bolt in your transmission pan:

Step 1: Assess the Situation

Before attempting any repairs, it's important to understand the extent of the damage. Inspect the transmission pan and identify the location of the stripped bolt. Check if there are any visible signs of damage or leaks.

Step 2: Gather the Necessary Tools and Materials

To use the hold-down plate method, you will need the following:

• A hold-down plate: This is a thin, flat piece of metal that will be placed between the bolts. You can purchase one at an automotive store or create your own by cutting a piece of metal to the appropriate size.
• Longer bolts: You will need two slightly longer bolts than the original ones to secure the hold-down plate in place.
• Tools: Ensure you have the necessary tools, such as a wrench or socket set, to remove and install the bolts.

Step 3: Prepare the Area

Before beginning the repair, it's important to create a safe and clean work environment. Place the vehicle on a level surface and ensure it is securely supported. Place a drain pan or container underneath the transmission pan to catch any fluid that may leak during the repair.

Step 4: Remove the Stripped Bolt

Using your tools, carefully remove the stripped bolt from the transmission pan. Clean the area around the bolt hole to ensure that there is no debris or residue that could interfere with the repair.

Step 5: Install the Hold-Down Plate

Position the hold-down plate between the bolts on either side of the stripped bolt. The plate should be large enough to cover the area and provide a stable surface for the new bolts.

Step 6: Secure the Hold-Down Plate with Longer Bolts

Take the longer bolts and insert them through the hold-down plate. Thread the bolts into the existing holes on either side of the stripped bolt. Tighten the bolts securely, but be careful not to overtighten them as this can cause further damage.

Step 7: Reattach the Transmission Pan

With the hold-down plate securely in place, you can now reattach the transmission pan. Line up the pan with the bolt holes and carefully thread the remaining bolts into place. Again, be careful not to overtighten the bolts.

Step 8: Final Checks

Once the transmission pan is securely attached, check for any leaks or signs of damage. Ensure that the bolts are tight and that the hold-down plate is securely in place. If everything looks good, you can lower the vehicle and consider the repair complete.

Drilling out the pan to a larger size

If you have a stripped bolt in your transmission pan, one method to remove it is to drill it out and replace it with a new one. However, this should be a last resort, as it can be challenging and there is a risk of damaging surrounding components.

Step 1: Prepare the Work Area

Before beginning any work, ensure your car is parked on a flat surface to ensure stability and prevent accidents. Use jack stands to lift the car and allow safe access to the transmission pan. It is crucial to be careful not to put too much pressure on the pan to avoid further damage.

Step 2: Drain the Oil

Place an oil collection receptacle beneath the transmission pan. Drain the oil from the pan to make it easier to work on and prevent spills. Remember to dispose of the oil properly.

Step 3: Attempt Other Removal Methods First

Before drilling, it is recommended to try other, less invasive methods to remove the stripped bolt. These can include:

• Using a wrench, socket and ratchet, or vice grips
• Employing a bolt extractor socket
• Applying penetrating oil and heat to loosen the bolt
• Using an impact wrench

Step 4: Choose the Correct Drill Bit Size

If the above methods are unsuccessful, it's time to drill. Select the correct size of drill bit for the bolt. This is crucial to avoid damaging the surrounding area.

Step 5: Drill a Pilot Hole

Start by drilling a pilot hole through the centre of the bolt. Use a drill bit that is slightly smaller than the bolt, such as a 1/8-inch metal drill bit. Ensure you do not drill deeper than the length of the bolt to avoid damaging the pan.

Step 6: Drill a Larger Hole

Gradually increase the size of the hole by using slightly larger drill bits. For example, you can use a 3/16-inch drill bit and then a 1/4-inch drill bit. The heat and vibration from drilling may help break the bolt free.

Step 7: Use a Bolt Extractor

Once you have drilled a sufficiently large hole, choose an appropriately-sized straight bolt extractor. Insert it into the hole and tap it firmly into place with a hammer.

Step 8: Remove the Bolt

Finally, twist the bolt extractor counter-clockwise to remove the remainder of the stripped bolt from the transmission pan.

Remember to take your time and be cautious during the process. If you feel unsure or uncomfortable at any point, it is best to seek professional assistance to ensure the bolt is removed safely without causing further damage.

Using a bottoming tap

To start, you will need to purchase a bottoming tap that matches the size of your bolt. You can find these at most hardware stores. It is important to get the right size to ensure a proper fit. If you are unsure, you can take the bolt with you to the store and ask for assistance.

Once you have the bottoming tap, you will need to clean the stripped hole and the bolt itself. Use a drill to create a new, clean thread, being careful not to drill too deeply and break through the hole. Then, use the bottoming tap to create new threads in the hole, following the instructions that come with the tap. Finally, insert a new, longer bolt and tighten it to the specified torque.

This method is a good alternative to other repair methods such as helicoil inserts or replacing the entire pan. It is less invasive than drilling and tapping to the next bigger size and does not require the additional steps of welding a nut over the damaged hole or using a thread repair kit.

Using a longer bolt

If you are dealing with a stripped bolt on your transmission pan, one possible solution is to use a longer bolt. This approach can be effective if the bolt hole has enough remaining threads to grip the longer bolt. It is important to note that you should not overtighten the longer bolt, as this can damage the soft aluminum mating surface.

When attempting to remove a stripped bolt from a transmission pan, you can try using a longer bolt of the same size. This may provide enough extra length to engage the remaining threads in the hole and allow you to remove the bolt. However, it is crucial to exercise caution and not apply too much force, as you could damage the threads further.

In some cases, you may need to use a slightly longer bolt to secure the transmission pan. This can occur if the original bolt was too short or if the threads in the bolt hole have been stripped. It is important to use a bolt that is long enough to engage the threads securely but not so long that it protrudes or interferes with other components.

If you are unable to find a longer bolt of the same size, you may need to tap the hole to the next size and use a larger bolt. This approach requires drilling out the existing hole and creating new threads to accommodate the larger bolt. It is important to use the correct tap drill size and to start with a taper tap before using a bottom tap to create the bottom threads.

Using a Heli-coil or Keensert

Heli-coils and Keenserts are both thread inserts that can be used to fix stripped bolt holes. They are available in different sizes, so you can choose the one that best fits the size and thread pitch of your bolt. Heli-coils are made from high-strength spring steel and come in kits that include several inserts, a thread tap, and an installation tool. Keenserts, on the other hand, are solid inserts made of hardened steel with tangs that you stake into place. They use standard taps, which may be cheaper than Heli-coil taps.

To install a Heli-coil, start by selecting the correct size insert kit and drill bit. You must use the specified drill bit size for the Heli-coil to work properly. Apply a liberal amount of grease around the hole and the drill bit to catch any metal shavings and prevent them from falling into the engine. Drill the hole as square as possible, using a carpenter's square to ensure the drill is straight. Once the hole is drilled, use the tap from the kit to carefully tap threads into it. Again, use grease on the tap and run it in square and straight. Thread the Heli-coil onto the installation tool, adding a little thread locker to ensure the threads stay in place. Carefully thread the Heli-coil into the hole until the top thread is just flush or slightly below the surface. Use a small punch to break off the tang at the bottom of the hole, and retrieve the tang with a small magnet.

For Keenserts, you will need to drill a pilot hole and then thread the insert into the hole, staking the tangs into place. The exact process may vary depending on the specific Keensert product you are using, so be sure to follow the manufacturer's instructions.

Both Heli-coils and Keenserts can provide a strong and durable repair for stripped bolt holes, but it is important to follow the correct installation procedures to ensure a successful outcome.

Frequently asked questions