After taking a road trip recently in the “58 I have come to the conclusion that the truck needs overdrive so the engine isn’t buzzing so fast at highway speeds. I’ve been doing some research and I’m leaning towards adding a Gear Vendors unit to the TH400. It will allow me to retain my current column shift, trans crossmember location and I can avoid buying a new trans and converter since this one has less than 10K on it. Anyone have first hand experience with the Gear Vendors set up?
They are fantastic and strong. Many are used at Bonneville and in motor homes. As long as you have the right rear gearing so they don’t cause a large drop or bogging you will like it.
I just went to the website and the cost is near 3k. How long will it take you to cover $3000 worth of gas?
With a 454 and 3.55 gears, probably not as long as you might think. The other option is a gear swap, it would be considerably cheaper but I’m concerned that going from a 3.55 to a 2.76 will make it a slug…
Just put taller tires on it! I had 3:50 gears in an OT truck with big tires….it was geared high for the highway……in a head wind, pulling a trailer …..too high! But with a 454…I would go with the high gears! Bones
It’s not so much the gas mileage, but winding of the engine. I’ve had two, one older small unit in a Ford PU I had for a spell, another I put in my parents MH (newer unit from the mid 2000’s) both worked great. Never an issue. I didn’t put the one in the pickup, but for the C6 in the MH they sent me a different tailhousing, output shaft I think? Been so long I don’t recall. But we were still able to use the same driveshaft. The ratings on them are shown (or were) more than your average built transmission.
Oh, another thing to note, the one I got for the MH was rebuilt at there place. It had I think an “x” in the serial number to show it was rebuilt and not new. Cost was 400/500 ? Less or so than buying new, but same warranty applied.
@squirrel has been running one in his Chevy II for a long time, it's survived a lot of miles on the road and a lot of trips down the drag strip, and a few Drag Week's. I haven't used one, but I think the idea is awesome, in effect doubling the number of gears you currently have; and they appear to be damn near bullet proof. I just wish they weren't so high priced....
I've had a Gear Vendors in my '53 Studebaker since I built the car in 2005. Initially I had a 640 HP 454/Turbo 400 with a tight converter and 3.23:1 rear gears. The overdrive gives me a final drive of 2.52:1, which I wanted for my land speed attempts with the ECTA and Power Tour trips. It worked perfectly. I actually got over 13 MPG with my blown big block. Then I decided to step up my game and build a blown Hemi. At the same time, I converted the transmission into a Switch-Pitch. The new engine made 1128 Horsepower, 851 ft./lbs. torque. It all went well for a couple summers, but then the Overdrive wouldn't engage. I burned up the clutch in it. I called Gear Vendors, and they were very good to me. I was engaging the overdrive under full power, right up near it's max rated capacity. Turns out, they also sell a stronger version that is good up to 2000 HP in OD. The guy offered to take mine in trade as a core for one of the beefier units, for an additional $600 (around 2014). The thing was totally solid thereafter. I like it, but it's a lot of $$$.
I have one in an ot pickup 454 t400 and lots of miles, works great. Start hunting for beater 80's motor homes for $500 to $1k and you'll probably find one.
IIRC, the GearVendor unit is a .78 overdrive. You'll get a 22% decrease in engine noise, but nowhere near a 22% increase in fuel mileage. BTDT. Question - what sort of cooling fan are you running? Fan noise can be a large percent of perceived engine noise. In one hotrod truck I was driving, changing the fan to a thermostatic clutch which never engaged at highway speed was about the same noise reduction as an overdrive with the fan. jack vines
I don’t think the OP was concerned about noise, but RPMs. I maybe jumped to him having a 3.90 rearend? I had my mind on a ‘58 Chevy PU.
They're great. I've scored a couple of used ones out of motor homes for $500. way cheaper then buying new.
The .78 overdrive would drop cruising rpm’s around 680 rpm’s @ 70 if I’m doing the math correctly. A 2.76 gear set would drop it by roughly the same amount. Cab noise isn’t the issue. My cooling fan is a thermostatically controlled electric pusher that seldom runs if there’s air flow. The cab has a full interior with extensive use of sound deadening. You can still hear the engine rumble, and it’s not at all objectionable. I just want to keep pace with the flow of traffic on an interstate without constantly turning 3000+ rpm’s. I would consider any fuel savings a bonus…
I have a GV overdrive in my 39 Ford coupe with a 302/c4 and 3.25 gears and it's great, in manual you can shift it in overdrive any speed over about 30 MPH and it will drop out when coming to a stop, or it also has automatic mode and will up shift about 45 MPH. The best part was I didn't have to cut the x member up to install it.
I put a3.54? in my ‘59 Chevy pu. 3k to almost keep with traffic was always wanting to swap to a T5. (235). Unsure of your power levels, etc. but a different transmission might be the same cost?
Mild 454, but I’m afraid the incidental costs that go with swapping the trans could drive the price even higher than adding a GV. Especially if I can find a good used one for less than MSRP.
Remember, the answer is always a quick change rear. Then you have whatever ratios you want. Probably the same cost also. With full floating gn hubs and axles, they're probably overkill, but you know the old adage. If some is good, more is better, and too much is just enough...
That's good advice, you'll probably get a 454 or 460 in the deal too! I have a question though. These motor homes with the OD, they are typically attached to a TH400 trans, right? That OD isn't going to fit a Powerglide, is it?
you have a mopar 83/4 rear, could you borrow a pumpkin with 2.76 gears. give a test drive to see it you like or not.
I'm paying attention to this thread. After a long trip without OD following a friend with OD, I decided it was a must have. I've just recently gotten my car on the road with the 700R4, and I have to tell you, the OD is life changing. I'm getting better milage than I ever have, cruising at 75+ mph, it's quieter in the car, runs cooler... It's honestly really nice. But the 700R4 has the finnicky TV cable, whereas the TH350 and TH400 are cheaper and easier with just a vacuum modulator. The GV unit is very appealing to retain a very basic trans and still have OD.
Squirrel runs one in his blown big block Nova that allows him to have strip gears to run tens and still be able to drive it on the highway. He is the one to ask. From looking at the one for a pickup with a turbo 400 I see that they want tire size and rear axle rato. I'm not sure if that is to give you the correct speedometer drive and driven gears or for another reason. Automatic 3-Speed T-400 Mech Speedo - Gearvendors 3095/00 isn't cheap but being able to gain 25 % on gas mileage means a hell of a lot more if you are getting 12 mpg than if you are getting 25 mpg to begin with. If you pulled that 12 mpg that would save you around 20 gallons per 1000 miles. at the price of regular here in town (3.85 at Safeway) that is around 77.00 per thousand miles.
As far as strength goes the Gear vendors OD goes it is very popular with the drag and drive participant's. Tom Bayley has gone 5.99 @ 250 mph in the quarter mile with one. I've considered one for my of topic mopar with 4.88 gears and 650hp and 620tq. Cash flow is the only thing holding me back....
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