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Thomas

Well-known member
Joined
Dec 28, 2012
Messages
134
Reaction score
5
Location
sweden
My Car
Boss 302 -70
Mach 1 -71
Thought the toploader was bulletproof. But I learned the hard way. Just buy new parts and try again. Do not know why it happened it was completely renovated when I bought it. And it has not rolled many miles.

// Thomas

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Very unusual failure. Contact this company http://www.4speedtoploaders.com for information about what could cause this failure and for replacement parts.

Chuck

 
I notice in your picture, the shifter mechanism has the boot around it. I bought and tried to fit one for a 70 Mustang as they (NPD) don't list one for the 71-73. It didn't fit. Mind you, I was on my back under the car. I know that my 71 did have one as parts of it remained.

Does the 70 part actually fit the 71? If not are the now available as repops?

Geoff.

 
A rare failure indeed. 4th gear?  No real way to tell at this point but I'd guess one of the teeth got chipped and failed under use. Those gears are very hard so they would need to likely get a crack from being dropped or forced together during assembly from someone unfamiliar with toploader assembly techniques. Complete renovation was unlikely because all the kits I've seen over the past 10 years have used plastic thrust washers. The metal copper lined ones may have simply been reused based on the preference of the builder, but if they were reused then what else was reused? The tarnished color of the brass synchronizer rings eluded to this transmission refurbishment not being recent and in my experience this was merely a cosmetic restoration.

 
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A rare failure indeed. 4th gear?  No real way to tell at this point but I'd guess one of the teeth got chipped and failed under use. Those gears are very hard so they would need to likely get a crack from being dropped or forced together during assembly from someone unfamiliar with toploader assembly techniques.  Complete renovation was unlikely because all the kits I've seen over the past 10 years have used plastic thrust washers. The metal copper lined ones may have simply been reused based on the preference of the builder, but if they were reused then what else was reused?  The tarnished color of the brass synchronizer rings eluded to this transmission refurbishment not being recent and in my experience this was merely a cosmetic restoration.
I WILL GET YOU SOURCE TOMORROW FOR ANY TOPLOADER PART YOU NEED.

 
Very unusual failure. Contact this company http://www.4speedtoploaders.com for information about what could cause this failure and for replacement parts.

Chuck
That seems to be a well-sorted company, should contact them.

Thanks for the tip !

// Thomas

 
I notice in your picture, the shifter mechanism has the boot around it. I bought and tried to fit one for a 70 Mustang as they (NPD) don't list one for the 71-73. It didn't fit. Mind you, I was on my back under the car. I know that my 71 did have one as parts of it remained.

Does the 70 part actually fit the 71? If not are the now available as repops?

Geoff.
The one in the picture is bought repro to 70 Mustang!

Bought two so I have a similar to my 70 Boss.

// Thomas

 
A rare failure indeed. 4th gear?  No real way to tell at this point but I'd guess one of the teeth got chipped and failed under use. Those gears are very hard so they would need to likely get a crack from being dropped or forced together during assembly from someone unfamiliar with toploader assembly techniques.  Complete renovation was unlikely because all the kits I've seen over the past 10 years have used plastic thrust washers. The metal copper lined ones may have simply been reused based on the preference of the builder, but if they were reused then what else was reused?  The tarnished color of the brass synchronizer rings eluded to this transmission refurbishment not being recent and in my experience this was merely a cosmetic restoration.
It is the input shaft as well as the corresponding drive on cluster gear that has broken.

It was renovated over 15 years ago, I bought it in 2004 so it's been a while since it was renovated. It was lying in the garage for a long time before the car was ready. Both the input and output shaft are new and it turns out that gear has not gone a lot. Looks new. So there is probably no bad renovation. However, it appears that the input shaft is a 3piece unit, do not know if they were worse than org 1 piece that apparently is available today.

But I'll ask David Kee!

// Thomas

 
I notice in your picture, the shifter mechanism has the boot around it. I bought and tried to fit one for a 70 Mustang as they (NPD) don't list one for the 71-73. It didn't fit. Mind you, I was on my back under the car. I know that my 71 did have one as parts of it remained.

Does the 70 part actually fit the 71? If not are the now available as repops?

Geoff.
The one in the picture is bought repro to 70 Mustang!

Bought two so I have a similar to my 70 Boss.

// Thomas
 Interesting! Personally, I could see no reason why the 70 version would NOT fit as it is the same box and shifter mechanism, although the opening in the tunnel may be slightly different. From what I remember, the opening in the rubber boot where it goes around the levers was not the same as the remains I took out on the 71. These are not cheap parts, but I may look at one again as I don't like the unprotected mechanism. However, the owner of the shop where my box was rebuilt, prefers not to use them as they can hold dirt in and cause damage to the mechanism. Hmmm!

 
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Good morning. The toploader is a strong transmission for sure but by no means bullet proof. My X broke third gear in one with a stock 351 with stock tires. If you have big tires they will break pretty easily.

Contact Dan Williams. http://www.toploadertransmissions.com/toploaderinfo.html

He has built thousands of them and keeps all the components to rebuilt to any spec you want. He will have the big input shafts and all the special pieces to beef up the transmission for you. He built toploaders for the racers for many years. He states that there are 133 different variations of the Ford 4 speed so you never know what you got. He also has the multi piece input shaft that allows only the defective part to be replaced, syncro, gear or shaft. Can also change ratio with it.

I have one of the easy to break models. It is from early production of the mustang 1964 1/2 that was only built for about 90 days. They actually did a recall they broke so easy. The output shaft was only 25 splines and would break with just a 289 4-V so Ford went to a larger 28 spline output shaft for 1965 models. It is one of the oddities of the 1964 1/2 models that you never hear about. But if you had a 1964 1/2 D code 289 4-V you got the 25 spline 4 speed. If you own of the few that got 289 HP you got 28 splines. The case only has 4 bolt holes in the pattern for the bell housing.

This is link to catalog for just parts. He will build the transmission for you if you want. http://www.toploadertransmissions.com/catalog.html

You would need to go with the much better transmission like NASCAR uses to get a more dependable model. There are also several different manual transmissions the drag racers use for big HP.. The straight cut gears are much stronger but are very noisy.

The toploader will break and keep breaking it was not made for the horsepower you can pull from today's technology and tires.

Good luck but plan on it breaking again there is always a weak link and if you have the HP and traction something is going to break.

 
Yes, finally my gearbox parts have arrived. Just start washing and putting it together.

// Thomas

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Thomas, with what engine have you ripped the Toploader apart? In my experience it takes streettires with 3400 lbs and a 572 cid 750 hp and you're going to brake the Nascar toploader. Not in the first or second gear but when it starts to hook.

 
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With the 572 Boss Engine !

When shifting from 2-3.

// Thomas

 
Thomas, with what engine have you ripped the Toploader apart? In my experience it takes streettires with 3400 lbs and a 572 cid 750 hp and you're going to brake the Nascar toploader. Not in the first or second gear but when it starts to hook.
They do break easier than you think with big tires and torque. My X broke one with a bone stock 73 351 C. Mustang. If you are going to have big HP and torque with big tires you have to use something better than a toploader.

 
The reason that the gear box broke was that the person who renovated it had put in the wrong input shaft. It only had 22 teeth and it should be 23. So it did not match the cluster gear. It has had a mysterious sound all the time on the first three gears. Now I know why. I prefer to do as much as I can by my self on my cars so I can not blame anyone else.

// Thomas

 
The reason that the gear box broke was that the person who renovated it had put in the wrong input shaft. It only had 22 teeth and it should be 23. So it did not match the cluster gear. It has had a mysterious sound all the time on the first three gears. Now I know why. I prefer to do as much as I can by my self on my cars so I can not blame anyone else.

// Thomas
Wow that was a big mistake. It had a bunch of backlash for sure. Just hitting on the tip of the teeth.

I know you already have your gears there. One thing that pretty much every part of the NASCAR racing parts go through is Cryogenic Treatment. Gears, axles, brake rotors, crankshafts, rods, engine blocks pretty much anything that moves or under stress is sent for Cryogenic. It totally changes the grain structure of the materials. You can treat a copper spot weld tip and increase it's life many times what an untreated is.

It is not just a matter of dropping into liquid nitrogen and freezing it. It has to be done in steps and for specific times and temperatures. It works and makes the parts last much longer. Here is a link to one of the suppliers. http://www.300below.com/motorsports/

I did some tests in our shop just before retirement it does work.

When I was in tool & die and when we made our own hand tools, grinding vises, squares, parallels, gauges, anything that required extreme tolerances sometimes +o.0000 - .0001" tolerances we would, after normal heat treatment and draw, boil the parts and put if freezer or nitrogen and do it repeatedly before we finish ground or lapped the parts. That removed all the internal stresses from the heat treatment process. They would stay accurate and not change with time. This was back in the 1960's

When we would build an engine back then you never wanted a brand new engine. You wanted one that had heat cycles on it so that it was stable and would not change dimension when you were racing it. New is not always a good thing especially anything made of iron like a cylinder block or heads.

There are probably shops that do this in your country also. It does do amazing things to metal no matter what kind of metal. The grain structure is much better after the treatment and parts just last longer and perform much better. I understand the brake rotors last much longer several 100% longer.

They also apply coatings that reduce the friction. When me and my son kart raced we sent all our engine parts and had coatings applied and never blew and engine in 7 or 8 years of racing. We used the coatings on our automotive tooling to reduce the amount of lube required and extend the life of the tooling.

With a mistake like they did in your transmission you did not stand a chance. Good that you found the error and have a good reason for the failure.

One other thing that this is great for is firearms. In the past when I bought a new rifle I would take apart and heat the barrel in oven to 200 deg. then put in freezer. I do this a dozen times. It removes the stress from the manufacturing process. Then I lap the rifle barrel before I ever shoot the gun. I am not a long range shooter but I do go to Africa a lot and take baboons at 500 meters with out any problem. There are companies the do just guns. You shoot a target before you send it in and then when it returns. They guarantee you a better group. I just wish someone would do a ceramic lined high powered rifle. That would be perfect. You could not burn it out and friction would be gone. They have been working on ceramic engine for years, no coolant, no lubrication. A local ceramics company here did a lot of development on it for Toyota but have never seen anything hit the market.

 
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IMG_0870.JPGIMG_0869.JPGDone! Just mount and hope it's working properly.
 
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