Manual Transmission FAQ

[keliente]

Manual Transmissions FAQ

1. What is the drill mod?

To sum it up, basically GM didn’t think things through all the way when selecting the hydraulic lines for your T56. The steel braided line that plugs into the master cylinder has a tiny, tiny hole in it, which causes unnecessary restriction. During a quick, high-rpm shift, fluid cannot get where it needs to go fast enough, so basically it will feel like you are shifting without a clutch. It may be difficult or impossible to shift into 2nd or 3rd, and you may have some problems with the pedal itself.

When performing the drill mod, you remove the master cylinder, separate the line from the cylinder, and drill it out. To visit a site with full information and pictures, click HERE. It will be listed under the Transmission section, along with the adjustable master cylinder install (although you can do the drill mod without changing the master).

2. Where the heck is the bleeder screw for this thing?

One of the more difficult things about a T56 is accessing the bleeder screw. You cannot see it without a mirror, so you must rely on feel. If you are beneath the car and you are looking at the transmission where the master cylinder line connects to the slave cylinder, reach straight upward. At the very top of the transmission you will feel a hex-shaped rod about two inches in length. That is the bleeder screw, which comes directly from the slave cylinder.

To bleed the system, you will need a 7/16th” socket, thin-walled, in ¼ drive. It would behoove you to use a few swivels and extensions. I also highly recommend taping the socket to the extension/swivel/etc. If for some reason you drop the socket, it will end up at the bottom of the bellhousing and you will have a hell of a time fishing it out.

If you plan to bleed traditionally, you will need two people. One under the car opening and tightening the bleeder screw, and another in the car operating the pedal.

If you are not squeamish about cutting into your car, you can make traditional bleeding a one man job. Underneath the car, do your best to put a dent in the transmission tunnel, straight across from the bleeder screw, with a punch. Get into the car and pull back the carpet around the pedals, and cut a small ‘access square’ so that you can also fold back the plastic, foam-lined piece beneath the carpet. Under that you will find the dent you made. With a 1” holesaw, cut a small part of the tunnel out. Now, with a 7/16” socket and a few extensions, you can reach the bleeder while being in the car! From here you can operate the pedal with your hand and use your other hand to tighten/loosen the screw. When you are done, simply put a piece of duct tape over the hole and recover with the carpet. It does not introduce any more noise into the cabinet.

Here is what the hole looks like (I had to drill mine a couple times to get it right)


3. Different options for bleeding the system

Your best bet for learning how to bleed would be to search this forum. People have posted many different ways of removing air from the system, from using a traditional way, a mity vac, etc. If you want to do it traditionally (whether by yourself or with help) it is very simple. The reservoir needs to be full of fluid the whole time, otherwise you will just continue to introduce more air into the system. With the bleeder closed, push the pedal to the floor. Open the bleeder (fluid and air will come out). Close the bleeder, release the pedal, bring it all the way back up. This process gets repeated until you have a firm clutch pedal. Don’t panic – it can take up to 30 minutes to get it bled correctly.

The fluid that dribbles out will end up in the bottom of the bellhousing, and it will seep out that rectangular hole in the bottom and take care of itself. If you would like, you can spray some brake cleaner into the cavity to speed the process along.

4. Is installing a clutch something I can do myself?

It depends. Do you have the appropriate tools, do you have strong jackstands to get the car HIGH in the air, are you strong, are you knowledgeable of how the transmission goes together? You can read a few clutch installation how-to’s and decide if you can do it or not. The transmission is very heavy so you will need to exercise caution when removing/installing it.

5. Nevermind, it’s not for me. How much will it cost to have it done by a pro?

Clutch installs range from $250 - $500 depending on where you take the car.

6. Can I use that old bread/wet toilet paper trick to remove the pilot bearing?

NO! This trick (which involves stuffing either bread or wet toilet paper into & behind the bearing to force it out) does not work because the area behind the pilot bearing is simply a freeze plug. If you force a lot of bread/tp into it, the bearing may come out but it can push that plug through the crankshaft and into the oil pan. This can cause an insane amount of oil to be lost, which in turn will ruin all of the friction material on the clutch. To remove the pilot bearing, either carefully cut it with a dremel tool, or use a very small puller for it (buy it or rent it from Auto Zone).

7. What’s the deal with 01-02 hydraulics? My 98-00 stuff seems to work fine.

If you are going to go through the trouble of dropping the transmission, you might as well change the master and slave cylinder while you are there. While your master & slave may be working okay now, it is a good idea to replace it with the 01-02 hydraulics anyway…because otherwise if your slave fails later on, you will need to take the transmission down again to get to it. The 01-02 has an improved design. Be advised that the line still requires the drill mod!

[cobra12345]

awesome thank you