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Discussion Starter #1 (Edited)
If you want to upgrade your current manual transmission to something that is track proven and stronger than a toploader/standard T10, perhaps you might consider a modern version of the old T10. They are available from various sources with upgraded internals. You'll have a choice of road race boxes or drag boxes with practically unlimited gear ratio options. These are racing transmissions with no synchronizers that shift like butter at higher RPM's or can be speed matched, double clutch driven much like a big rig at slower speeds.

I recently destroyed my Jerico and needed something stronger. After comparing all my options, I decided to upgrade to a Gforce G101A clutched 4 speed. The Gforce facility is located a couple of hours from here and the owner has been trying to get me to install one for several years.

I considered a 5 speed but it requires an inline shifter to work flawlessly. Since I street drive my car, I wanted an H pattern shifter so my best bet ended up being the 4 speed.

I ran down to the Gforce factory and got the tour. The 101 design started out as a T10 and Gforce (and others) made them stronger for Nascar usage--to the tune of being able to handle 1000HP/900lbs torque. Since my Jerico was only good for an estimated 750hp max, the Gforce was a good upgrade in that respect. I talked with the owner's son about my needs and he sent me home with an empty 101 case, a tail housing, a billet yoke, and a poly tranny mount. That allowed me to get a head start on the installation while my 101 was being custom built.



Gforce has Strange build their billet yokes:



Poly mount is the same as would be used in a Chevy:



A search of the internet revealed only 1 site that detailed a 101 being installed in a 65/66 Mustang. There was 2 different tech articles for the installation:

Mustang T101 Crossmember | GTSparkplugs

Mustang T101 Transmission Swap | GTSparkplugs

I found the articles useful, but not all inclusive for my needs. (A T101 was made by Tex racing, which is now owned by Gforce. Both are pretty much the same transmission. )

Because the 101 has dual bolt patterns, it bolted right up to my Ford scattershield with almost no issues:




Unfortunately the hole that I used with the toploader/Jerico's racing clutch adjustments was covered by the larger 101 mounting flange. This required I drill another hole in the scattershield for the adjustment:



This will work:



I was able to rework the Mustang's transmission cross member to mount the 101. I simply added 2 new slots to my previously modified cross member:



Success:



I test installed the parking brake mechanisms and they fit perfectly below the 101 tailshaft:



Bolted on the driveshaft loop for testing:



Its a little shy of where it should be. Since the 101 is a couple of inches shorter than the toploader/Jerico, a longer driveshaft needs to be made. Although the old one was aluminum, the new one will be steel as I have just about came to the strength limits of an 3 1/2" diameter aluminum shaft.

The old driveshaft will still be useful as I retained all the car's mountings to reinstall a toploader for extended street use.
 

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Discussion Starter #4 (Edited)
Nice write up. Thanks Dennis. Looks like a really nice tranny. Care to share where their price points are?
$4800 all new or $4K refurbished (both include a new Long Shifter) directly from Gforce.

They will accept partial payments until its paid off.
 

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$4800 all new or $4K refurbished (both include a new Long Shifter) directly from Gforce.

They will accept partial payments until its paid off.
Now that's a hell of a business model. I have often wanted to ask Shaun if he has any payment options like that but have been embarrassed to have to do so.

And I assumed that's where they would be in the market. Actually, that's not a bad price considering, (and I may be wrong) that's cheaper than Road Race Jerico which doesn't include a shifter.
 

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Now that's a hell of a business model. I have often wanted to ask Shaun if he has any payment options like that but have been embarrassed to have to do so.
A savings account with automatic transfer from your paycheck is the easy way to do that. You don't see the money in your paycheck so you don't spend it.
 

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I have often wanted to ask Shaun if he has any payment options like that but have been embarrassed to have to do so.
I'm sure we can work something out. :wink:

I can just write you an invoice and apply your payments to it when you make them.
 

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I'm sure we can work something out. :wink:

I can just write you an invoice and apply your payments to it when you make them.
Wow...that's awesome. If others were not aware of this, you might want to stock up on parts.

EDIT: Apologies for the hijack there Dennis. Looking forward to that next installment of pics. Video would be nice too.:grin2:
 

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Discussion Starter #12
I picked up the fully rebuild 101 from Gforce last week. It came with the Ford BB input shaft/bearing retainer, wide drag race gears (softer than road race), a GF4 output shaft, a GF4 Magnesium roller tailhousing, and a GF4 Magnesium side cover. Even with all the aluminum and Magnesium, this puppy is heavy. Because I wanted an H pattern shifter, they set me up with one of their road racing rail shifters with chrome moly rods:













Although Gforce can match how far a shifter is mounted fore and aft of the transmission, they cannot match the Mustang's center mount shift handle location. The height came into question too. Since I only wanted to have minimal interference with the transmission tunnel, I set about to make my own mount. Here is the Gforce mount that came with the tranny:



I started with a piece of cardboard and drew out a potential mount, which I transferred to a thin piece of aluminum to verify fit on the tailhousing:



I then transferred the design on to a plate of 1/2" thick aluminum:



Gf4 tailhousing is narrower than the typical 101. (Most parts are interchangeable.)





Version 1.00 of the homemade mount on the tailshaft:



The tapered holes was an attempt to get the shifter as close to the tailhousing as possible using minimal shims. I installed the transmission after cutting some of the LH side of the shifter hole away. There is no way it will fit without some cutting.






(The yellow tape is the outline of where the old shifter boot was mounted.) You can also see the aluminum block that Gforce gave me to help locate the shifter further toward the center of the tunnel.

The problem with Ver 1.0 is that it located the shifter too far toward the rear of the car so the handle would hit the tunnel shifting into 2nd and 4th.

I took what I learned from the first attempt and built a 2nd bracket, Version 2.0:



This one moved the shifter forward 1" and down an extra 1/8". It incorporated shims to move the shifter away from the transmisson, which allowed me to move the shifter forward and keep the shift rods from binding against each other.

Good shot of the rail shifter:



Note that its rods come out of the front, not the bottom like a Hurst.

The little hoop on the pin is used to align the shifter rods to the transmission when it is in neutral:



The chrome moly rods are adjustable:



When I moved the shifter forward I did not have enough adjustment so I shortened the upper 2 rods about an inch and the lower reverse rod 1 1/2". A tap was used to thread the inside of the rod so the rod ends could be reinstalled.

The new shifter location was a good improvement over the first version. The shifter is now centered in the hole, fore and aft:



Although the shifter hole needed to be enlarged by 1" on the driver's side, there was no need to reshape the tunnel for the shifter or for rod clearance.

Some additional clearancing of the transmission cross member was required so the transmission revers shift lever could have full travel:



Rods clear the tunnel horseshoe brace without modification:







The tailshaft vent is ultra tall and rather than replace it with an elbow and a rubber hose, I did heat and bend the horseshoe bracket for clearance. You can see the vent in one of the photos above.

Completely installed, including parking brake assembly:



Because the 101 is shorter than the toploader, a longer driveshaft was needed. Since I felt I was on the fringe with the old 3 1/2" aluminum shaft, I went with 3 1/2" steel which should handle all the power I ever plan to put to the ground now and in the future. The changes that were made to the car does not prevent me from reinstalling the BBF toploader any time in the future. Simply unbolt the 101, and install the toploader with the old driveshaft.

One thing I noticed about the 101 that I thought was weird is that the rear seal appears to be installed backwards with the tension spring facing the driveshaft. Gforce use one guy to build all the 101's so I decided to let it alone. Even after a few mile ride, not 1 drop has passed by the seal.



Now the best part--driving impressions on the street. As expected the straight cut gears are a little loud, but not unbearable. It is easy to shift into and out of gears by speed matching the rpm's. After I felt comfortable during the outing I put the pedal to the metal and shifted 2nd, 3rd, and 4th gear without using the clutch. It was done almost effortlessly by heeding the builder's advice--move the shifter every time like you hate it. I'm still grinning from the ride . . . . .

The real test should be this Friday when I take it to the track.

Because the shifter hole was widened, it will require a wider boot. For now I covered it with a Supershifter boot I had on the shelf, but plan on doing some research to find one somewhat smaller that will still cover the shifter hole.
 

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Dennis, Thanks for the great write-up and results. I am saving this so when I break my TKO I can look at this path.

Tony
 

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Discussion Starter #16
I found that I couldn't get a clean shift with the Gforce at full throttle. If I left off the gas or used the clutch it would work fine but simply pulling or pushing the handle as recommended at full throttle resulted in a slow, uncertain shift action. It would come out of gear when IT was ready and go into the next gear with equal hesitation. I knew the car was much slower because it ran it out 3rd gear in the 1/8 instead of the typical shift to 4th about 75' before.

I tried leaving off the gas a little to shift which made it easier, but that slowed the car down too. I probably left off too much. Also tried clutching it but the car didn't seem to recover quickly. Basically I was discombobulated being without the Jerico and couldn't find the rhythm needed to have a clean uneventful run.

I believe there wasn't enough mechanical leverage to yank/slam the handle quickly at higher RPM's. It shifts good at lower steady RPM's but under full throttle it's being locked into place by the backcut on the engagement teeth. The backcut is what keeps the transmission from popping out of gear on the return road or cruising the highways.

You may recall, this is the handle as it was installed before going to the track:



The shifter is in neutral in the above photo and has an extreme angle toward the rear of the car. Being so long and low it doesn't appear to give me the needed leverage to manhandle the shifts.

Since the handle is easily removeable from the top of the shifter AND the mounting holes are drilled the same spacing as the Hurst handles, I went to work on something different.

In my scrap bin I had an old retired Hurst shifter handle that was made for my red GMC to clear the bench seat. Obviously it was too long to use in the Mustang but after messing with it for a little while I discovered that the metal is not hardened as I had thought. That meant I could cut and retread as necessary.

I first cut off the top few inches of the handle



and discarded it. A grinder was used to make the top of the stub round so it could be threaded for a knob. I also heated the bottom to bend the handle a little closer to me. The result was a nearly upright handle that allows me to apply full leverage fore and aft. To increase my odds of a clean shift, a Hurst T handle was installed for more grip:



(If I get good with it, I have a ball to put on top like before.)

This rendition should give significant leverage to row between the gears. It's still a little on the long side which requires more motion fore and aft, but being its an H patter shifter it needs more movement than an inline. (A longer handle is supposed to be the cure for the inlines too.) If it works, I will trade my new "Long" handle for a similar shaped one from Gforce.

If it doesn't work I have a few more options. The easiest would be to set the rev limiter down to 7500 to allow the engine to bounce off it at the shift point (which should help with the gear release) OR I could go back to shifting it with the clutch like I did the Jerico. Its also possible to trade the clutched sliders for the split clutchless type but that option is not good for street use.
 

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Discussion Starter #17 (Edited)
I took it to the track with the new handle and didn't quite get the results I wanted. The instructions from Gforce was to manipulate the shifter like I hated it. I struggled with it and the best I could do was pull as hard as I could and it would eventually (and slowly) slip out of one gear and then into the next. I couldn't make the gear change without hurting my fingers from all the force that needed applied. It drove sweet on the street but was slow and in-concise shifting flat footed at 7500rpms. I was a little pi$$ed.

I then tried an old racer's trick and set the rev limiter to my 7500 shift rpm. As I went down the track I put moderate pressure on the shifter in the direction that it needed to go and when it hit the limiter, the transmission lugs unlocked and I was able to move it quickly into the next gear. The maneuver still requires some force, but its much, much less than I was applying before. I made all 3 shifts this way.

At first I found that the MSD limiter/shift point came at 7200. Since tachs and rev limiters don't always coincide, I changed the limiter to 7700, which gave me close to the desired 7500rpm shift that I wanted. It now shifts quick and hard enough for the interior mirror to move out of position and the trunk mat bundles up against the tail light panel. I never had that effect flat footing and clutching the Jerico. I'm now looking forward to the next race night.
 

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Discussion Starter #19
I bent the shifter handle to the left a little more (closer to my leg) and took it to the track. The rev limiter was put back at 8200 to take it out of the shifting equation so I could experiment with other options. Of all the different combinations I've tried, pulling the 2nd gear shift clutchless and then bumping the clutch for the 3rd and 4th shifts worked the best using the H pattern shifter with the G101. This gives the advantage of a fast clutchless shift to overcome the worst gear spread ( 3.17 to 1.96) and then using the clutch for the other 2 shifts giving minimal rpm droppage since the spread is much less (1.96 to 1.34 to 1.1). After shifting the old Jerico with clutch taps the last couple of years I've gotten pretty good at it.
 
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