Gear Vendors Unit

Transmissions and Rear Ends

  1. SouthBay

    SouthBay Member

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    Has anyone put a gear vendor overdrive is our cars? I have a '87 Fifth. Trying to plan what direction I want to go but whatever I choose I know I want some sort of overdrive.

    If anyone has done it, does any of the floor need cutting?

    I know the Chrysler 4spd's take some massaging and fabrication of the trans tunnel to make fit. I'd rather not cut the floor if I can avoid it.
     
  2. Aspen500

    Aspen500 Well-Known Member

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    I've not installed one in an F/M/J body Mopar but have put them in a 1971 Mercury and '69 Charger at work. The Merc only needed a slight "massaging" of one spot in the tunnel for the speedo cable adapter and the Charger fit with no mods, that I can recall off hand. They are fairly small and from my rough measuring, an F/M/J would need only a small amount of tunnel clearance adjustment in one area. Don't take that as an absolute though. At any rate, you won't need to do any floor cutting, only reshaping with a hammer at the most and even then, it won't be much.

    I'd love to put a Gear Vendor's in my car also. The thing that's stopping it happening basically is $$$$$.:(
     
  3. Duke5A

    Duke5A Well-Known Member

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    In all my travels across multiple Mopar boards I have never seen one in an F/M/J. Seen plenty of 500/518 conversion though myself having done two of them.

    OD ratio in the GV is not all that great vs 500/518 too. I think the GV is only .80 and the Mopar alternative is .69.

    On the cheap you can do a 518 conversion for under a grand, but yes, it involves surgery to the tunnel.
     
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  4. Magnum Aspen

    Magnum Aspen Member

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    I put a gear vendors unit in my B body about 15 years ago. No floor or cross member modifications were needed. It even worked with the console shifter. The drive shaft did need to be shortened and rebalanced at high speed. Also caution is needed to be sure the exhaust is routed far enough from the shift solenoid to prevent it from getting overheated,which causes issues with shifting.
    The unit is comprised of an adaptor which replaces the tail housing on the transmission and attaches to the factory mount these are unique to each brand of transmission, the actual unit is attached to the adaptor. The combination is longer than the original trans. The adaptor for Dodges is long and skinny.
    It is not a deep over drive gear, but I find that it makes 3.73 gears useable on the highway.
     
  5. AJ/FormS

    AJ/FormS Well-Known Member

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    My GVod is .78, and into an A-body, it only needed a few hammer swings to get the clearance it needed; IDK about your Fifth
    But I gotta say with an automatic, I highly recommend the A500/A518. And the reason is because of the .69overdrive. This will allow you to run absolutely any rear gear you want to. So if you optimize the rest of your combo for street work, then you can let the .69 od claw your say 4.56s back to a sane 3.15, and 65=~2550 in loc-up. Badaboom
    Do you need 4.56s? Probably not, so that makes it even more attractive.
    Let's say you just wanted to be quick to 60mph.
    The quickest you can get to 6, is by going thru your power peak twice, and ending on the power peak the second time. With a given engine, you can do no better.
    Ok so with an A500 the ratios are; 2.74-1.54-1.00-69
    and 60 mph with say 4.30s, and 27" tires in 1.54 second gear , would be 4936 at zero-slip, say 5200 at 5%. and say the plateau is 300 rpm so you can pick a cam to peak 200 to 300 rpm sooner And I get About a 212@.050. That's a pretty small cam. Could be about a 262 advertised. and, these 4.30s will cruise at 65=2210.

    Ok but say you want to go faster.
    So with 4.56s now,the rpm at 60 mph is 5235@zero-slip so say 5500 at 5% slip, and the cam could peak at -300=5200. That would be two sizes bigger or a 224@.050, which could be a 268advertised. See how easy this is? And with the 4.56s your rpm at 65 mph will be ~2540 in OD

    Ok but say you are going for mpgs WITH performance, and you already have a stock 5.2 Magnum.... with its factory 250/264/110 cam in it. Well first thing to do is to retime the cam to in at 106 to make some serious pressure. Then, from what I have researched, that cam is a puny 182/194 @.050. so it's gonna run like an old LA318 as to advertised, which makes it peak at about 4200rpm, and the 110Lsa is gonna give us 400 rpm so you are gonna want to hit 60 at no more than 4200+400+200= 4800. Enter the math; and 3.91s come up; which cruise at 65=2180 in loc-up. Easy peasy.

    Ok I know what your thinking, you can't split gears with the Mopar TFs. Well with these gears, as described above, there is no need to nor opportunity, in a two gear run to 60. Besides, the ratios don't split the best when you do.
    If you bolted a GVod onto a an A999, you would get 2.74-2.14-1.54-1.20-1.00-.78od ...GVs in red
    and the splits are; .78 -.72-.78-.83-.78 into overdrive. Hey that looks pretty good.... right?
    But think about it;
    at the top of 1.54 second gear, you are doing 60 mph. Now on the split from 4800 @60 mph your Rs are gonna drop to .78 =3744(with the GV).... but using direct the Rs fall to 3116. Hey that looks good too right? That looks 657 rpm better.
    But go look on your power curve, how that little Magnum cam works is this; there is very little power difference over that 657 rpm. So you are paying $$$$ for very little gain in splitting, and you still have to get out of the OD unit into third, which cannot be done under power, so you are gonna have to lift, and when you do, ouch, any or most of the gains you made in that 657 rpm are instantly lost in the lifted-foot out-shift. daymn.... So now all the GVod was good for is the 1-2 split plus cruising.
    As to the 1-2 split, forget about it, cuz 1) you still have to deal with the lift-foot out-shift, and 2) the tires are gonna be smoking into second gear anyway, cuz your starter gear is 2.74x3.91=10.71, plus about 10% or more in the Tc =11.78; So there you go; 4800 into second comes at 36 mph with tires blazing.

    OK so what about with the bigger cams?
    Same problems but with even more gear like 4.30s and 4.56s, traction in first gear at WOT is impossible... so all that extra power just goes into tirespin and an earlier mph upshift.

    So what's the answer?
    IDK, my tires spin to 80mph and higher, and they are 295s so bigger tires, by themselves are not the answer. When you solve that,cheaply, lemmee know.

    One thing I can tell you is this;
    For a streeter, limited by a 65mph speedlimit, big-power is just bragging rights. oh and let's not forget
    big fun
    until it isn't any more.
    Like when you get pulled over, or crash, or the engine blows up, or something breaks. My engine broke a lotta things.
    The most fun you can have is the right amount of power at the right time,.... and with a given engine,that always leads to the right gear at the right time, with a fairly flat torque curve. However, when cruise rpm is not an issue, and you have two full gears to play with from zero to sixty....there is never a shortage of power even with a decent 318. Some of my best memories involve a factory stock 318LA from 1973 with just a 4bbl and headers........ and radical for street, gears. Like 4.30s behind an A999 and no overdrive. Yeah 50@2670 wasn't the best,lol, but thru the gears was POW!, wicked.

    Ok here comes my point
    Since I like the A500/518TFs so much, and they have proven themselves over and over, do this; just get yourself a second HD rear end for your car and bolt yourself some big-number rear gears into it, and see how you like it. The only thing that the A500 will give you beyond this incredible kick in the azz, is a cruiser gear. Then you will be able to tell right away if the A500 is in your future. And you will be so impressed with that slug of a 318 under your hood, that you may decide to leave it alone .......... at least for a while. It already has the right cam for 3.91s. And if you put some better springs on it so it can reliably rev to 5000 plus, then I see 4.10s.= 4940@5% slip =60 mph, yessiree.
    The rear gear is the whole purpose of running an overdrive, so why not just start with it! Then you'll know if spending the money on the A500/518 is gonna be worth it........... to you.

    Those od-TorqueFlites are not bolt-ins, I'm sure you know that, but the crossmembers are now being fabbed up for us, which makes the job so much easier, and usually cleaner too,lol.

    Happy HotRodding
     
    Last edited: Dec 29, 2019
  6. Oldiron440

    Oldiron440 Well-Known Member

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    To damn long toredr
     
  7. SouthBay

    SouthBay Member

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    -edit-
    You have to forgive me, I followed some of that but got lost on the gear splitting part. I know .69 ratio is way better than .78. I've had plenty of cars and old cars before but this is the first time hopping anything up beyond chopping the muffler off. I'm not too knowledgeable about what you were talking about.

    The rear end I definitely want to get a 8 1/4 with 3.55 maybe. With the gear vendor unit I'd be turning around 2,100-2,200 rpms at 65 if I remember right.

    I have put gears in a car before. I had a Chevy that I put 3.73's in and immediately knew I needed a fourth gear. Much smaller tire on that but I think I was closer to 3k rpms at 65.

    Essentially I'm looking for 4spd that won't need too much fabrication. I thought the Mopar units needed major surgery for it. If the floor will look the same and I don't have to move the seats out floor plan on the inside I think if be okay with it.

    If I do get a Mopar od I'd have it rebuilt before putting it in the car. I was looking at the gear vendor unit because it seemed easier and about the same price after a rebuild. I have a fresh 904 in the car right now.
     
    Last edited: Dec 29, 2019
  8. Magnum Aspen

    Magnum Aspen Member

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    The GV unit is basically a complete transmission that is attached to the existing transmission. The GV unit can be engaged with the existing transmission in any gear.
    When the GV unit is engaged with the existing transmission in a gear other than third, the effective gear ratio is between the existing transmission gear ratios. The GV manufacturer calls this "gear splitting". The GV website has a much better explanation.
    I have found this to be not particularly useful as the engine in my car with the GV unit makes lots of torque. I would not worry too much about it, but do your own research.
    The previous owner of my Aspen had an A500 installed. The transmission cross member had to be modified and a new mount fabricated. It was not cheap, I remember him complaining. I suspect the seats and carpet had to be removed to complete this modification. I am not sure what if any floor pan modifications were necessary, but there are other threads that detail 4 speed installs. I can say that the original seats and carpet still fit.
    Other things to consider is that A500 transmissions will probably require some means to operate the OD and torque converter lock up electrically either with some switches as the previous owner of my car did or with a transmission controller.
    I chose a GV unit for my B body because I did not want to modify the cross member or floor pan and it is a big block car which is more difficult to adapt a 4 speed auto to.
    For my Aspen I plan to retain the A500 or the A518 from the engine donor vehicle given that the cross member has already been modified.
    Given that the 904 is fresh, the cost of installation and crossmember modification and the cost of a reman a500 transmission I think you are right that a GV would be about the same price, unless you can do the work yourself.. This is just my opnion however.
     
  9. SouthBay

    SouthBay Member

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    Wish I could do the work myself so I can learn. But I doubt my apartment complex would be cool with me chopping up a car in the parking lot :)

    Trust me, I'd prefer to use a Mopar unit. Depending on costs to have the floor modified I would rather go that route. I was thinking of the gear Vendors due to ease of install.

    I'll probably have to call around and talk to a couple shops. I'm new to Austin, TX but I've been told there are a lot of good speed shops around.
     
  10. Duke5A

    Duke5A Well-Known Member

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    Yeah, I'm going to agree that a GV is your best bet here. It was close knowing your 904 is fresh, but toss in the fact you don't have a garage to work in, that seals it.

    Honestly, this isn't going to be cheap. The $4k for the GV and parts alone, with probably $1.5k for installation...you sure you want to do this? Even a cherry Fifth Avenue is barely worth half of what you're going to spend.
     
  11. SouthBay

    SouthBay Member

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    Hey I paid $500 for the whole car. Title and insurance was almost more than what I paid for it.

    I had the trans rebuilt because it was shot. Then a carb rebuild with all new vacuum hoses.


    My wife loves the car almost more than I do. Definitely not getting rid of it. That's why I want to do everything right and save up for better parts.

    Like I said I do want to change the rear end out but I want to keep the rpms as low as possible to keep the engine happy for longer. I plan on building up the motor slightly sometime down the road.

    I'm not made of money though so I want to get things right the first time. Thats why I asked for advice hopefully someone can speak from experience.
     
  12. Oldiron440

    Oldiron440 Well-Known Member

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    You could find a much nicer version of the car you have for that kinda money. Lower mileage better overall condition.
    Look at it this way it got buy this many years just fine without OD a few more won't make a difference.
     
  13. BudW

    BudW Moderator Staff Member

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    The Gear Venders unit is not cheap. That said, short of the shift solenoid problem(s), they are indestructible (…almost) behind any engine. They can also be carried over to another vehicle without much issue if you get the correct adaptor housing for it (assuming a different transmission type or even different brand).

    Personally, I would rather use a A500/A518 myself – but have not personally modified a car to make one fit (yet).

    In my case, I have a choice between big block A727 with a GV unit vs. A518 and an aftermarket big block bell housing.
    It will be more cost effective for me to go with the A518.

    A few random pictures:
    JW Performance Ultra Bell 92460.jpg
    Big block to A518 (or A727) bell housing

    A727 vs A518.jpg
    A518 (top) vs. A727 (bottom).
    Note: the A904/A998/A999 is about 4" shorter than an A727 is.

    727 GV.jpg
    An older ('68 or '69?) B-body A727 with Gear Venders attached.

    iuSFOWMD51.jpg
    An A833 (4-speed manual) showing tail housing length difference (for comparison).
    BudW
     
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  14. SouthBay

    SouthBay Member

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    The A518 doesn't look that at much bigger than the 727 aside from the tailshaft being bigger. Is that where floor modifications need to happen, further back the trans tunnel for the tailshaft?
     
  15. Duke5A

    Duke5A Well-Known Member

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    Yes, tailshaft forward it's the same transmission. Where it interferes is the where the crossmember follows the contour of the tunnel.
     
  16. SouthBay

    SouthBay Member

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    So is it a matter of fabricating a new crossmember and hammering the floor? Or does the tunnel need to be cut and made bigger?
     
  17. AJ/FormS

    AJ/FormS Well-Known Member

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    Thanks to BudW for the great pics.
     
  18. AJ/FormS

    AJ/FormS Well-Known Member

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    The cross-member is being fabbed up by the aftermarket.
    But yes the upper hoop of the factory crossmember needs to be modified and re-inforced to endure as the Torsion-bar forces go directly into it, and the floor has to be split open to provide clearance. That is actually the easy part.

    Formerly, fabbing the cross-member was the hard part.
    Now, modifying the upper hoop is the hard part.
    But I think the factory carpet still covers the work. See Trailbeasts gallery over on FABO. He is "extremely" pleased at how well the whole thing worked out for him. and He's a great guy to talk to.
     
    Last edited: Jan 1, 2020
  19. SouthBay

    SouthBay Member

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    So are there any other options out there? As I do more research and what I've learned here too, either option is expensive.

    Like I said I plan to upgrade the rear end, somewhere a around 3.55 ratio. Engine wise I haven't decided on a 5.9 magnum or building the current 318. Not going for a winning race car here, just something fun. Maybe around 300-350hp. Just something fun off the line or on a freeway on-ramp.

    But with a 3.55 ratio that means the engine would be at 2800+ rpms at 65. Over 1,000 rpms more than the stock 2.2 ratio. That has to be to high of a rpm for an engine to be at, am I right?
     
  20. Oldiron440

    Oldiron440 Well-Known Member

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    2800 rpm is no problem, and you can buy a lot of fuel with the cost of the OD because your going to need to drive a lot of miles to pay for it.
     
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