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Discussion Starter #1
So I took the plunge and bought the GV unit and Im at a stand still. Parts are not fitting like they are suppose to and I called GV with no help. All my problems are about the speed sensor and adapters they supply. I have an FMX trans in a 732 Mustang.

They supplied 2 o rings to fit into the speedo tube adapter. A small fat o ring and a larger skinny o ring. These o rings don't fit either end of the speedo tube adapter! My existing speedo cable end that would normally push into the transmission and has a metal piece and a bolt retaining it to the transmission just falls out of the replacement speedo tube adapter. GV says to remove the existing oring and install their supplied o ring and it is more of a press fit. The o rings they sent don't fit.

They supplied about a 1 inch speedo cable extension that is suppose the fit the end of my existing speedo cable and fits into the speed senser through the spped tube adapter. Problem is , the 1 inch adapter does not fit my cable. It has a square end on it and it is a real sloppy fit on my speedo cable to the point that it will just slip and not lock in. It is square shaped and the square is larger than my cable. My speedo cable is original and works just fine and fits the ford speedo drivin gear for my FMX.

Can anyone help with this?
 

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I have a NOS GV toploader kit in the garage that I have yet to fully install. I too have all the parts that you mentioned but haven't messed with them yet other than look at them. I doubt if my speedo drive parts are any different than what you found in your kit.

I'm leaving town tomorrow but if I get the chance in the morning I'll test them on a speedo cable to see what happens and give you some feedback. Otherwise it will be sometime next weekend.
 

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I have found several issues with the GV instructions when I was messing with stuff a few months ago.

I piddled with the speedo kit and a couple of Ford Speedo cables i have laying around. Here is what I determined:

1. The small parts bag is a universal kit for more than one type of transmission. Neither of the O-rings in the kit are correct for our usage. Probably one of the many reasons that they recommend a professional installer do the work . . . . . Anyhow,

The O-ring is only being used as a speedo cable retention device as there is no fluids that need contained. I found that if I use the original Ford factory O-ring with the adapter the speedo cable remains snug in the GV aluminum adapter. A new O-ring may be needed (mine worked great) for total snugness but since the O-ring is only used for retention an old one may also work just fine. Alternately you could drill and tap the side of the adapter and add set screws for total security. Probably not needed unless it tends to vibrate out on its own.

2. The 1 1/2" or so cable adapter has the same male "square" widths as the original speedo cable (approximately .102".) The male squares fit fairly decent in the speed adapter with only a little slop. On the other hand the female part of the square has a sloppy fit (mine doesn't "rotate" on the speedo cable) although there is about .015-.020" of slop that probably doesn't need to be there.

The cleanest route would be to install a universal speedo repair kit. The kit contains just the center of the speedo cable and you cut it to length and do a little crimping with the included tool. About $5-$15 max. Your doing this just to add an additional 5/8" (max) to the inner cable in order to insert it into the new speed sensor.

I may go that route or more than likely mess with the included part by either trying to crimp it onto the old cable OR bottom it out and braze/silver solder it in place on the cable center.


I have a question for you--did you purchase a 90* speedo cable adapter for on the transmission? Curious as to how much one costs.
 

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I put one in my '78 F350 car hauler behind the C6. The only issue I had was the one Dennis addressed in his note #2. I went to AutoZone and bought the econo speedo cable replacement kit JUST for the crimp on end. That worked PERFECT and finished the installation. The unit works flawlessly as if it were an AOD instead of two units. I used a couple of zip ties to keep the adapter together.
Randy
 

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Discussion Starter #5
I put one in my '78 F350 car hauler behind the C6. The only issue I had was the one Dennis addressed in his note #2. I went to AutoZone and bought the econo speedo cable replacement kit JUST for the crimp on end. That worked PERFECT and finished the installation. The unit works flawlessly as if it were an AOD instead of two units. I used a couple of zip ties to keep the adapter together.
Randy


Its funny, I bought one of those speedo repair kits before I posted here. It seems to me that GV didn't put much thought into that aluminum adaptor.
Thanks for you opinion.
 

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Discussion Starter #6
I have found several issues with the GV instructions when I was messing with stuff a few months ago.

I piddled with the speedo kit and a couple of Ford Speedo cables i have laying around. Here is what I determined:

1. The small parts bag is a universal kit for more than one type of transmission. Neither of the O-rings in the kit are correct for our usage. Probably one of the many reasons that they recommend a professional installer do the work . . . . . Anyhow,

The O-ring is only being used as a speedo cable retention device as there is no fluids that need contained. I found that if I use the original Ford factory O-ring with the adapter the speedo cable remains snug in the GV aluminum adapter. A new O-ring may be needed (mine worked great) for total snugness but since the O-ring is only used for retention an old one may also work just fine. Alternately you could drill and tap the side of the adapter and add set screws for total security. Probably not needed unless it tends to vibrate out on its own.

2. The 1 1/2" or so cable adapter has the same male "square" widths as the original speedo cable (approximately .102".) The male squares fit fairly decent in the speed adapter with only a little slop. On the other hand the female part of the square has a sloppy fit (mine doesn't "rotate" on the speedo cable) although there is about .015-.020" of slop that probably doesn't need to be there.

The cleanest route would be to install a universal speedo repair kit. The kit contains just the center of the speedo cable and you cut it to length and do a little crimping with the included tool. About $5-$15 max. Your doing this just to add an additional 5/8" (max) to the inner cable in order to insert it into the new speed sensor.

I may go that route or more than likely mess with the included part by either trying to crimp it onto the old cable OR bottom it out and braze/silver solder it in place on the cable center.


I have a question for you--did you purchase a 90* speedo cable adapter for on the transmission? Curious as to how much one costs.


I figured I would try a new oring and see if it will help keep it into the adaptor tighter. My o ring is pretty old. I did purchase one of those repair kits for the cable before i posted here. I didn't try it yet. I did not purchase a 90 degree adapter but I inquired about it when I called them a bout my issues. It is $135 and that doesn't include a smaller cable you will need. I guess I got a few different thing to try but disappointed so far in GV.
 

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I installed a GV unit in my 62 F;lane, this was almost 10 years ago now so my recall of the install is somewhat hazy. I do know I had issues with the speedo install & called Gear Vendor, they sent me to the local GV dealer here in Ontario, Canada. A couple hours later I was back shifting madly, I recall the mechanic telling me he used a universal speedo adapter & would bill GV for the cost of it.
Now, almost 10 years later I;ve had no issues whatsoever. At first, I did find it clunky shifting sometimes, but, when we switched to a small block stroker motor the change to a looser stall convertor, (2800) seemed to fix this issue.
Your going to find the C-4/GV combo allot of fun to drive, believe me!!
Royster
 

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My Gear Vendors gear splitter works great. I've never had a problem for 5 years. It just bolted onto the C6, and a new driveshaft and that's that. The C6 has the 5 and 6 clutch plates and the 1/2" wider band, and it's a state of the art all aluminum, 482ci 427 with an enormous amount of horsepower and torque. A lot more than a normal 500hp mediujm riser 427, which I have 300,000 miles in.


The advertising is kind of deceptive, saying it's a 6 speed. In a race, you would never ever use more than 4. 3.5 really. 1, 2, 3, 3.5. I just use it as an overdrive. Sometimes I put it in second and switch between 2 and 2.5 for city driving, using the floor switch. I guess pulling a trailer up Fancy Gap in the Smokies, it would be nice to pick from 6 gears. If you try to use all 6 in a race, which doesn't work, and you got confused and hit the floor switch wrong, it could overrev the engine.



It has a thing where you can start it first, then it switches from 1 to 1.5 to 2.5 to 3.5, but I would only use it on a drag strip, where 2.5 is the right gear for the end of the track, and there's good traction. It's a real hard shift, and breaks the tires loose when you hit 1.5 on that first shift. But this engine squeals the hell out of the tires in a normal automatic shift at 4000rpm and half throttle, and risks spinning them on a bad road at 6000 rpm, so the much harder shift into the power band is only if you want to impress observers by lighting up the tires in second. Which, with posi, is suicidal.



Like an aluminum engine, it's all plusses, no minuses, I'd strongly recommend the product.
 

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Discussion Starter #9
Ok so here is where im at at with my install so far. I used the universal speedo repair kit and used just the end and crimped it to my existing speedo cable and that eliminates the end piece that didn't fit my original cable and that seemed to work. Next I ordered a 90 degree adapter to fit on the overdrive unit. I didn't spend the $130 that GV wanted for it. I bought one from a Corvette shop near me and it cost $60 delivered to me in 2 days. This adapter fits other GM transmissions.The speedo in the GV unit is a GM so that was easy. Next I drilled and tapped that aluminum speedo adapter and put a set screw in it to keep the speedometer cable from just falling out. This is something that GV should be doing. Next I went to HD at bought a piece of aluminum that was 1/8" thick and 2" wide and made a bracket out of it to support the speed senser and aluminum adapter. I also fell that GV should supply something similar. Than I took the 18" speedo cable they sent me that is just WAY too long and cut it down so it fits perfect into the 90 degree adapter. Its now just 4". Thank you for your ideas and tips. Next is measure for a new drive shaft and wire it up.
 

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I didn't spend the $130 that GV wanted for it. I bought one from a Corvette shop near me and it cost $60 delivered to me in 2 days. This adapter fits other GM transmissions.The speedo in the GV unit is a GM so that was easy. Next I drilled and tapped that aluminum speedo adapter and put a set screw in it to keep the speedometer cable from just falling out. This is something that GV should be doing.
Good job in figuring it out.

Would you be so kind as to pass on any info that you might have about the 90* adapter? GM part #, or years used/type tranny, or even their phone # so I can get find cheaper? The internet has been of little help for a 1:1 adapter.

Thanks.
 

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Figured since this thread could be used as a future reference for others that I'd add a little more info:

Found this little 90* unit on EvilBay for $40 delivered from a vendor who goes by "thecorvetteshop":








Its heavy, appears to be very well made with brass and steel construction, and uses minimal clearance in the tranny tunnel. It can even be dissembled for cleaning if desired. Includes a nice double male link bar adapter from the box to the transmission speedo gear. It was originally designed as a Corvette distributor tach drive but should work great in its new application.

The short 6 or 7" speedo cable shown came with my GV toploader kit. I will make a different attaching bracket for the sensor.

Here is a link to the current Part # for the recommended fluid to be used: https://www.summitracing.com/parts/ADO-10-4119

The # 10-4119 fluid is the replacement for the GV recommended GM#12346190 synthetic GL4 (that has been discontinued by GM) for street use.

The only thing that I have left to figure out is the attachment from the Ford's center speedo cable to the speedo drive. What I have found so far (including the GV supplied attachment) is quite sloppy. I do have some leads though plus plenty of time to sort it out to my liking . . .
 

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Discussion Starter #12
Dennis, that's the same 90 adapter I bought and it works fine. As far as putting the Ford speedo cable end into the GV adapter, I drilled a small hole and taped threads into the adapter and put a set screw into it and that worked great. Its something a think the GV should have done to begin with. As far as fluid goes, I used Dextron 3 which is what my instructions said to use. I noticed you posted about using some AC Declo synthetic fluid? I may try that. The GV unit shifts kinda harsh and maybe that fluid will make it shift a little easier. I emailed GV but never heard back from them.
 

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Dennis, that's the same 90 adapter I bought and it works fine. As far as putting the Ford speedo cable end into the GV adapter, I drilled a small hole and taped threads into the adapter and put a set screw into it and that worked great. Its something a think the GV should have done to begin with. As far as fluid goes, I used Dextron 3 which is what my instructions said to use. I noticed you posted about using some AC Declo synthetic fluid? I may try that. The GV unit shifts kinda harsh and maybe that fluid will make it shift a little easier. I emailed GV but never heard back from them.
The main purpose of the AC Delco synthetic GL4 fluid is that it softens the shift.

My GV manual calls for the gear lube (unless one is racing and fast shifts are desired (then Dextron 3 is recommended.) There are lots of references to the Delco Gear lube on the net but remember that its original # has been superseded.

Simply drain out the Dextron and refill. If you don't like the shifts you can always go back. GV recommends going back and fourths to those who race and then use the vehicle normally.

The manual also suggests an alternate Mopar equivalent fluid (with a different part #) that can be used too.
 
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