[Ken N Gilbert]

I acquired a 67 GTO convertible this spring and, I should be beaten, because I bought it online. There is a confession. I started it after 6 months of working on it and it sounded great. It came with a 3 speed and I so naturally I took it for drive to check the clutch and the slippage was disappointing. I could hit the brake and with clutch out and not kill the motor (that type of diasappointing). I am not close to the level of car guy that most of you are but I have recieved great information from the members at this site so here goes the question. I dropped the transmission out today because I thought the clutch was shot and the clutch looked ok. Not new, but certainly not totally shot. The transmission and bell housing were a bear to get off the block. I am no expert, but it sucked. I may have cussed a time of 10 during the process. After looking at the 'not shot' clutch I turned my attention to the transmission. On the case of the transmission there was FoMoCo stamp. Is there a chance it could that be GM transmission or is it as stamped? How much (approximately) should a 4 speed muncie be to repalce it with either way. My budget has been kicked in the nards so many times my only saving grace is this site.

[b-man]

Ford supplied the 3-speed transmissions to GM for quite a while during that time period, nothing out of the ordinary. A Muncie 4-speed trans is in the $500 to $1500 range depending on whether it's a good used one or a rebuilt/new one.

Even though the clutch 'looks' good perhaps the pressure plate is worn and lost spring tension/holding power. While you're in there, definitely replace the pressure plate and clutch disc and resurface the flywheel it it needs it.

You slippage problem could be related to a linkage adjustment issue, if the pressure plate wasn't fully engaged you'll have slippage.

[Ken N Gilbert]

Thanks B-man. I was a bit worried about the FoMoco stamp but I think it convinced me to move to a 4 speed anyway.

[400 4spd.]

If you switch to a four speed you will need to change the driveshaft yoke because the splines are not the same as a Muncie. A yoke from a Turbo 350 sourced driveshaft will work behind a Muncie.

[GT182]

Ken, unless you want keep a stock 4 speed, have you thought of going to a 5 speed? Yeah more money and a bit more work, but for mileage and less wear and tear it could be a good option. There are guy's here at PY that have done it and say it's the best thing they did. Just a thought to slip in for ya.

[Ken N Gilbert]

GT182- A good night sleep and more thought about swap out has me interested in the idea of a 5 speed. The motor is correct but not original and I want a very drivable car so everything is on the table now. In other words I would not be shaming a numbers correct car. I am going through information saturation right now so can you share a good place to start with looking into a 5speed or other type of replacement tranny.

[Singleton]

Unless you are dead-set on getting a transmission with overdrive, (which would be very nice btw), consider keeping the 3-speed. Do a search on this site on "Dearborn toploader", and you will see that many consider it as strong or stronger than the Muncie 4-speed, (M-20 & M21). There is a 1/4 mile drag test result somewhere here, between the 3-sp and the 4-sp that showed no difference in e.t.
Just food for thought..

[geeteeohguy]

I'm with Singleton. Especially since you state that you're not a mechanic or fabricator. Nothing wrong with a stock 3 speed stick...and a hell of a lot rarer and more interesting than a "yet- another- converted- to- 5 speed car", IMO.

[Satyr1966]

I have been driving and checking out '66 & '67 GTOs since the early '70s & I have never seen a 3 speed in one in person. This includes being at 3 GTO National Conventions. That may give you some indication of their rarity. I imagine a lot of 3 speed cars were changed over to 4 or 5 speeds, but even so, you might want to consider hanging on to it just for the rarity factor. From the way you described your slippage it sounds like the clutch, not the trans. While you're in there, you should think about replacing the throw-out bearing too. Best of luck! Jerry.

[400 4spd.]

I have 2 Dearborn's that I got about 1974. One was in a 65 GTO, the other a 67 GTO. Both cars were totaled out.
I used one of them in my 67 GTO for a few years with no problems. In fact it was better than the 4 speed for lots of in-town driving, with a loooooong 2nd gear.

[Ken N Gilbert]

More good information. You can't get this kind of feedback anywhere. I had no idea the 3 speed had an upside. I haven't driven it yet so I don't know the driveability but I think I will put it back in while I am making up my mind. I spent all day in the driveway replacing the clutch and I just can't get the tranny to go back into place. I put it away for the week and I'll try to go at it agian next weekend.

[Satyr1966]

If you didn't get the clutch disc exactly centered, the trans nose won't want to go into the throw-out bearing. The way to remedy this is to get the clutch linkage all hooked up & have someone depress the clutch pedal while you push the trans in. Having the clutch pedal depressed allows the disc to move around a bit so you can find the opening in the throw-out bearing with the nose of the trans.

[gtos4ever]

Originally Posted by Satyr1966

If you didn't get the clutch disc exactly centered, the trans nose won't want to go into the throw-out bearing. The way to remedy this is to get the clutch linkage all hooked up & have someone depress the clutch pedal while you push the trans in. Having the clutch pedal depressed allows the disc to move around a bit so you can find the opening in the throw-out bearing with the nose of the trans.

I believe you mean pilot bearing, not throw out. Pilot is in the end of the crank, throw out engages pressure plate fingers.

[ctgross]

Back in the "day", I had the tranny out of my 66 4sp. seemed nearly every week I had a wood Dowel type rod I bought at some parts house. Plug it in with the bolts slightly loose, wiggle it till it slides in/out smooth and tighten the bolts. It looked like a short broom handle. It will make stabbing the tranny mucho eaiser.

[Andre]

Could be as simple as the adjusting rod is set too long, or you have the wrong clutch to Zbar rod. Easy fixes first before yanking it apart.

[valkyrie9901]

May be weak springs in the pressure plate.......Rebuilt ones esp. cheaper ones don't checked for equal force and allows the clutch to slip.........JB.

[GT182]

Keisler has 5 and 6 speed trannies. Gear Vendors makes overdrive units for automatic and manual trannies. These are 2 that I'm familiar with, and they are not cheap by any means.

Keisler.... http://www.keislerauto.com/Keisler_A...gineering.html

Gear Vendors.... http://www.gearvendors.com/

Here's a PY thread on a 6 speed conversion by 6D6Goat...... http://forums.maxperformanceinc.com/...eed+conversion

[marshallbeach]

4 speed GTO.

Just sounds right.

[Rugratman]

ken, welcome.
Do a search Ken, When I was putting my stuff back together, I tried to document all the steps, and problems.
There was allot of tips and tricks posted.

I say leave the 3 speed for now. Its a good trans. If the clutch was slipping, you would smell it.

[Satyr1966]

Sorry, senior moment. I did mean pilot bearing not throw-out bearing in my previous post.