66 tranny fill

[Ed K.]

Gentlemen, cannot get the tranny fill plug out of my 66 BB. Tranny probably empty since a previous constant tranny leak stopped during a 2 year resto of the entire rear end. Square bolt head is now crumbling at corners. I've been told heat may crack the aluminum tranny housing. 4 spd tranny still in car and I'm working with front raised on jackstands. An hour or so lift time may be available.

[Edward J.]

Re: 66 tranny fill

Ed, there maybe some sort of sealant on the threads that are keeping the plug from coming out, you may need something like a propane torch to slightly heat to soften the sealant, its all you can do at this point.the propane torch does not heat like a acc. and oxygen tank system do. so about a 30-45 sec. heat time is about all you'll need, heat it around the the plug its self. I have done this before on rear axle fill plugs.

[Ed K.]

Re: 66 tranny fill

Thanks. A tranny rebuilder at a respected local speed shop has had aluminum tranny casing cracking problems when applying heat. He cautioned me to be prepared to replace the casing if I heat it. I'm recession-jobless and can't chance that route. I tried some brief propane heat without success. I'm hoping to find a solution using strictly mechanical or chemical means.

[Jim T.]

Re: 66 tranny fill

Gentlemen, cannot get the tranny fill plug out of my 66 BB. Tranny probably empty since a previous constant tranny leak stopped during a 2 year resto of the entire rear end. Square bolt head is now crumbling at corners. I've been told heat may crack the aluminum tranny housing. 4 spd tranny still in car and I'm working with front raised on jackstands. An hour or so lift time may be available.

Edwards post mentioning rear axle fill plugs reminds me of my first jobs in the early 60's working in a gas service station. Servicing an auto I tightened the a non-Corvette's filler plug so tight that it broke and the threads of the filler plug were still threaded in the rear end. I thought I had really screwed up the rear end. Went to my boss and told him what I had done. He came to the garage and went under the car still on the lift. He reached to the threads and just started unthreading them.
From later experience trying to remove the filler plug on my 68 Corvette M21's from the case, the plug would not break. I ended up rounding the corners to much trying to get it out while the transmission was in the car.

I don't know what the best or even reccomended solution is to remove a filler plug from a Muncie. If the square end of a socket will fit on the plug and using bolt in the other end of the socket and using another socket on the blot with a breaker bar may remove it.

Another way is to remove the transmisson and use an impact wrench using the square end of a socket.

With the transmission out of the car drill into the filler plug but not through the plug with a small bit, and using larger bits remove enough metal that using a cold chisel you could break the plug towards the center of the plug removing some of the threads until the plug can be removed.

Perhaps the best way is remove the transmission and take it to a automotive machine shop that has a EDM service.

[Larry M.]

Re: 66 tranny fill

Gentlemen, cannot get the tranny fill plug out of my 66 BB. Tranny probably empty since a previous constant tranny leak stopped during a 2 year resto of the entire rear end. Square bolt head is now crumbling at corners. I've been told heat may crack the aluminum tranny housing. 4 spd tranny still in car and I'm working with front raised on jackstands. An hour or so lift time may be available.

What wrench(s) and or sockets are you using??

I have had my best luck with a 12 inch Crescent Wrench (don't try with anything smaller). Use some WD-40 on the wrench adjustment mechanism so that it moves VERY smoothly (so you can cinch it up VERY tight against the square filler plug. Spray some Kroil on the threads for a few hours or occasionally throughout the day...some may get into the filler plug threads and help lubricate.

Then attach the Crescent Wrench, cinch it up to the filler plug head TIGHTLY and then loosen the plug. If it won't budge, get a wrench extention (cheater pipe) and try again.

I would not use heat. If you still can't remove the plug, consider removing the trans and let a machine shop with EDM do it.

Larry

[John H.]

Re: 66 tranny fill

Ed -

Are you using an 8-point socket?

[Ed K.]

Re: 66 tranny fill

Hi. I've used an 8 pt socket with a 9" ratchet. After failing used a Sears spiral bolt removal socket which led to the bolt corners crumbling.

I began soaking the bolt with PB Blaster once or twice a day last week. PB is a favorite amongst Long Island wrench guys. After applying I then put a 3/4" diameter rod on the face of the nut (the rod now parallel to the threads)and tap a dozen times. Then place the rod vertically against the 4 sided nut and again tap, hoping to break it loose. So far no luck but I will continue this until tomorrow.

[Joe L.]

Re: 66 tranny fill

Gentlemen, cannot get the tranny fill plug out of my 66 BB. Tranny probably empty since a previous constant tranny leak stopped during a 2 year resto of the entire rear end. Square bolt head is now crumbling at corners. I've been told heat may crack the aluminum tranny housing. 4 spd tranny still in car and I'm working with front raised on jackstands. An hour or so lift time may be available.

Ed------


I've been "down this road" once-upon-a-time. Unfortunately, I have to tell you that I don't think you'll get this plug out using any conventional or non-destructive means. Somehow or another, these cast iron plugs seem to practically "weld" themselves to the aluminum case. It may be galvanic (dissimilar metal) corrosion or it may be some other phenomenon. The only way I know of to remove these plugs is to drill them out by using increasingly larger drill size until the remaining plug is paper thin. Then, using a sharp-pointed awl or similar tool, remove the remaining cast iron. Of course, the transmission has to be disassembled to do this.

Here are some other "interim" solutions I have actually used in order to be able to be sure the transmission has fluid in it and to add fluid:

1) Grind the external "stub" of the plug's square head flat. Then, drill and tap it for a 1/4 or 3/8 NPT pipe plug. In this manner you will have a "plug-within-a-plug". It will be smaller OD than the original and you won't be able to get a finger in to check level, but you will be able to get a bent wire in to check level (like a little dipstick) and you will be able to add fluid. When you drill and tap, you have to be very careful to absolutely minimize any chips that get into the transmission. As careful as you can be, some might get in. However, the magnet in the transmission should capture any that do get in just like it captures other steel wear material from the transmission (when you open up a Muncie that's been in long service you will be amazed at the amount of metal captured on this magnet).

The downside to the above procedure is that you pretty much have to have the transmission out of the car to do this. But, you don't have to disassemble the transmission.

2) With the transmission in the car, you can drill and tap a hole in the side-cover for a 1/8" NPT pipe plug once again being very careful to minimize any chips that get into the transmission. Some will, of course, and the magnet is not going to help you here, but the material is soft. Install the plug at about the same relative "height" in the transmission as the filler plug so that you can use it to confirm correct level as well as add fluid. You will use a bent wire "dipstick" to check the level, just as described above.

Someday, when you rebuild the transmission you can simply weld up the hole using Muggyweld rod and grind so that the repair is virtually invisible.

Some photos are attached of both the "plug-in-a-plug" and the side cover plug.

[Larry M.]

Re: 66 tranny fill

Hi. I've used an 8 pt socket with a 9" ratchet. After failing used a Sears spiral bolt removal socket which led to the bolt corners crumbling.

I began soaking the bolt with PB Blaster once or twice a day last week. PB is a favorite amongst Long Island wrench guys. After applying I then put a 3/4" diameter rod on the face of the nut (the rod now parallel to the threads)and tap a dozen times. Then place the rod vertically against the 4 sided nut and again tap, hoping to break it loose. So far no luck but I will continue this until tomorrow.

Ed:

A 9 inch ratchet is too short. If you use a 8 pt socket, then get a 3/8 x 1/2 inch adapter and use a 14-16 inch long 1/2 inch drive BREAKER BAR. Buying these tools (if you don't already have) is probably cheaper than just about any other fix.

However, I still recommend the 12 inch Crescent Wrench (plus cheater bar if needed) on the square filler plug. Better than a socket, in my opinion. This is probably the only place where I would recommend a crescent wrench over other tools for Corvette repair.

Larry

[Ed K.]

Re: 66 tranny fill

Just got home from a holiday party. Back to the real world.

Larry - I'll try the crescent wrech after more liquid wrench and hammering. 8 Pt no longer works due to rounded crumbled corners. I have a large adjustable parallel smooth jaw wrench which I'll try.

Joe - Plug-in-plug interesting. Would get me through summer driving and then in fall remove tranny.

ALL - After a few scotches, someone at the holiday party suggested jack car up on drivers side, remove speedo gear assembly and fill through hole. Then in fall take tranny out.

Everyone - Thank you for your participation. I'll let ya know outcome

[Joe L.]

Re: 66 tranny fill

Just got home from a holiday party. Back to the real world.

Larry - I'll try the crescent wrech after more liquid wrench and hammering. 8 Pt no longer works due to rounded crumbled corners. I have a large adjustable parallel smooth jaw wrench which I'll try.

Joe - Plug-in-plug interesting. Would get me through summer driving and then in fall remove tranny.

ALL - After a few scotches, someone at the holiday party suggested jack car up on drivers side, remove speedo gear assembly and fill through hole. Then in fall take tranny out.

Everyone - Thank you for your participation. I'll let ya know outcome

Ed------

With the corners of the plug head wrenching surface rounded, I think your chances of getting the plug out in a non-destructive manner are just about zilch. Even with the plug head absolutely perfect your chances wouldn't be much better, but they'd be a little better.

Lesson to be learned from this: when you finally do get the plug out make sure that you ALWAYS use anti-sieze compound on the new plug.

[Larry M.]

Re: 66 tranny fill

To get through the summer, filling through an alternate casing hole is a good idea. But you don't want to overfill.

I would get the exact trans oil capacity from Owners Manual or Shop Manual and then add that amount. If your occasional drip starts back up, you were empty and are now "good to go".

However, if in doubt or you think you might have overfilled, remove the driveshaft yoke and elevate the front of the car about 15-20 degrees (front tires off ground about 4-6 inches). Excess gear oil should drain out the rear seal.

I just finished installing my driveshaft....trans was at proper oil level, and I got just a few ounces of gear oil out the rear when I jacked up the front for undercar access. (No lift...do my repairs the old-fashioned and time-tested way )

Larry

[Edward J.]

Re: 66 tranny fill

Ed, Larry,s post may have a idea , how about removing the front part of driveshaft and yoke and jack up the rear of the car as high as saftey permits and squeeze in some gear oil the tail shaft of trans. that way, with a plastic bottle of gear oil and there is a small tappered nipple that is supplied with those Qt. bottles.just a idea. Ed

[Larry M.]

Re: 66 tranny fill

Ed, Larry,s post may have a idea , how about removing the front part of driveshaft and yoke and jack up the rear of the car as high as saftey permits and squeeze in some gear oil the tail shaft of trans. that way, with a plastic bottle of gear oil and there is a small tappered nipple that is supplied with those Qt. bottles.just a idea. Ed

Ed should leave the 90 wt oil out in the hot sun for a few hours before trying to squeeze through that small bottle nozzle opening

Larry

[William F.]

Re: 66 tranny fill

Have you tried a "freeze spray" to shock loosen stuck plugs, bolts, etc.? I believe loctite and John Deere make these products-I saw it at a Jonh Deere tractor dealer recently.
Good luck!