US Gear Overdrive question

[Lektrikman]

I've got a 95 EC, LB, 2WD, 5SPD, and I'm considering the installation of a US Gear overdrive unit on the back of my NV4500. The intent is to lower my highway cruising RPM for a quieter ride and maybe a bit better mileage. Anyone have any experiences, pro or con on the US Gear units or the affects on the NV4500? Any comments would be appreciated. Thanks, Lektrikman

 

[wbrown02]

I can't tell you much about the US Gear... . I had a GearVendor installed on my 95 5 speed with 3. 54 gears..... Here is what you get..... Much better fuel mileage... . I got 23 mpg at 75 mph in 5th overdrive... . I had a trans temp gauge..... almost no trans heat while towing up to 23,000 combined vehicle weight... . towing in 4th and overdrive... . as soon as you used 5th gear to tow the trans heat goes way up ... never happens in 4th over... . My 95 had over 90k on the clock and never a 5th gear nut problem... . and motor was not stock. Hope this helps. Liked it so much I am having one installed on my 05 in about a week.

 

[Supermod56]

On the 4500, it is a good idea to replace the tail housing with the cast iron one, the stock aluminum housing tends to crack when you hang a O/D unit on it. That's what I'm doing on mine.



Tom

 

[wbrown02]

I believe the gearvendor replaces the stock alum housing..... on lthe NV4500?

 

[Supermod56]

Maybe on the 2WD, but on the 4X4 it replaces the housing on the rear of the transfer case, with the weight of the G/V hanging on the end, it tends to crack the stock housing where the T/C bolts up.



Tom

 

[Turbo Thom]

I've had mine on about 4 years. The US Gear. I never had a cracking problem but last year I changed to the cast housing when I replaced the transmission, again. I never saw a milage increase but I also had 406 HP and a heavy foot. RPM's are a good bit lower and towing it really keep the engine in the rpm band. Since I replaced the injectors with the 215's, I really need the over-drive unit.



. . Preston. .

 

[DKarvwnaris]

I believe the gearvendor replaces the stock alum housing..... on lthe NV4500?

It replaces the 2wd housing as stated above. For the 4wd, it replaces the tailshaft of the transfer case. The aluminum housing on the NV-4500 transmissions can tend to crack with the overdrvie units on them, but it is easily prevented with an additional crossmember added around the Gear Vendors bolt pattern on the transfer case mount up. I have fabricated a few to lighten the load on trucks in the past. My current dodge is still in need of an overdrive, just haven't bothered since I bought my big volvo hauler.



I have seen Gear vendors go over 300,000 miles before needing repair. They will rebuild your existing unit or send you an exchange unit with a claim ticket to return your dead unit with. (Usually for around $400 to $500 depending on how much your retailer marks it up).

The Gear Vendor units can also be found on medium duty trucks friom years back. They used to be used on Volvo MDT's. It is one of the reason's Gear Vendors is so protective of their adapters for each vehicle application. A gear vendor will give you warning it is having problems as it will flash codes from its interface box. You will also experience problems with going into reverse before it goes out completely usually. I lost reverse 1,200 miles before forward motion gave up. I knew better and still drove it due to being away from home on business.

As for the U. S. Gear models. -:t

I was not happy with mine, I had very poor results with it and not so good service from them when I needed help getting it replaced. They shift very hard (compared to the Gear Vendors), usually will clunk in between ranges. I have heard they have improved their design a year ago, but I will never give them a second chance. I owned one a few years ago with nothing but problems. I have installed a few for friends and customers, they didn't get much better results with theirs. If used for light duty hauling and on a budget, I would possibly consider them, but overall the Gear Vendor is a much better unit.

 

[Turbo Thom]

Each to his own but I do not want anything hung on the rear of my transmission that acts like an automatic transmission. I've been shifting 8 years and I'll keep like that. Noise and and all.



. . Preston. .

 

[MNorgren]

I agree with Preston, I'd rather shift. The US Gear unit works very well. The clunk is minimal once you learn how to shift it. I found, shifting during RPM drop made the transition barely noticeable. Like anything else, take care of it and it will give good service.

 

[Loren]

Lektrikman,



I have a US Gear unit on my six-speed and love it.



If you can wait until the next issue of the TDR comes, it should have my article in it that discusses issues involved in getting an overdrive transmission. I'm assuming that Robert is going to print it since I got a check for it.



One of the things I discovered is that you will get slightly better mileage, but not much better. You certainly will NOT pay for the overdrive unit with fuel savings. The best thing you can do to improve fuel mileage is still to slow down.



If you want the quiet of somewhat lower cruising RPM's and the ability to split gears, which is very handy for towing, then get the overdrive. Just don't kid yourself that it will pay you back the cost of the installation.



After I installed mine, I found that my cruise control would not work at higher speeds. I attributed this to vibration from the drivetrain and built a rubber shock mount (got the parts from McMaster-Carr) to support the rear of the overdrive. It cured the problem. If you are concerned about hanging heavy objects off the back of your transmission (and I think you should be), consider fabricating a mount.



This installation is not simple. If you are not very mechanically capable, you probably should have it done at a shop. US Gear's instructions stink, and you'll have to figure a lot of things out for yourself.



For those who have a 4WD six-speed, be aware that some configurations of drivetrain and wheelbase will require that you shorten the fuel tank. It can be done, but it's not easy to find a plastic welder who will do the job, plus you lose 4-5 gallons of fuel capacity. Check the clearance behind your transfer case before you decide to do it.



As I said, I love mine, and consider it one of the best accessories I've installed on my truck.



Loren

 

[Graphic man]

My Dad has a US GEAR under drive in his 2000 F350, he tows combined weight of 26,000lb and has never had any problems, he loves it.

 

[Sasquach]

Im a new member and this is my first post. I have a 92 350 4x4 with the 3spd auto, and was wondering if an overdrive unit was the way to go. like the rest of you, id rather be rowing a shifter, but the truck only had 49K mi and i picked it up for $12000. I was thinking of converting it to a manual, but the truck's in too good of shape to be cutting on. I just cant handle cruising at 50mph anymore. thanks, chuck

 

[Gary - K7GLD]

"I just cant handle cruising at 50mph anymore. thanks, chuck"



Chuck, I had a US Gear OD unit installed on my '91 (3. 07 differential) with a 727 3-speed automatic - it was a BIG help in lowering engine RPM at cruise out on the freeway, and SOME help in pulling our 5th wheel in the hills (it depended on the road conditions and grade %). I didn't see any fuel MPG savings, but the reduced engine RPM alone was worth the cost.

 

[Turbo Thom]

Personally, I can't help you with the US Gear on an auto. I would think a GearVendors would be the best application there. I really don't know. .



. . Preston. .

 

[pepecat]

Sasquatch/Chuck - No od for me...

I have a stock '89 with 727 3 spd and 3. 07 gears... When I first started driving the truck I was convinced that it was "undrivable for long trips" due to the fact that I had to be 3/4 to WOT on I-5 (70 MPH speed limit in CAL). It is loud, sounds like the engine is ready to scatter and seems like it is WAY undergeared... HOWEVER, as much as I would've killed for a G. V. or US gear OD unit, I am glad I didn't go thru with it because I realized that the truck is not a gasser, hence it has different drive qualities, that frankly, were very similar to the CAT powered Freightliner fl60 I used to drive WOT @ 65 MPH. (auto as well) I got used to my dodge over time, but there are ways to get the truck to breath better and get better MPG on the highway without tweaking the drivetrain. I was running 17 MPG AVG until I installed a BHAF (read: BIG HONKIN AIR FILTER LIKE THE BIG RIGS/FARM TRACTORS USE ) I am getting over 19 MPG consistantly, with less than 3/4 thottle and the turbo is real nice sounding! I drove in the pouring rain from L. A. to Sacramento last night and the exposed BHAF (you need to remove stock air filter box to install, easy to do) was bone dry, and I was not only getting rained on, I was getting back spray from the big rig's tires in a big way straight into the front of the truck... (needless to say I had to pull over a couple times after getting hammered just to ensure that everything was still dry and happy). These non OD trucks have the 727 auto which has been used in many applications (like gas trucks and behind hemi hot rodders) and don't mind being turned as fast as these cummins are goverened, chrysler got this trans built right a LOOONG time ago, so no harm there, (and the cummins engines are rated to operate at full thottle all of the time with no harm to the engine, I believe it is actually good if not better for the engine to be operating in the high revs for many reasons IMO just look at recipricating aircraft engines which can handle 100% power operation for 2000 hours (equivilant to 200,000 miles on a land vehicle) (sorry I am an aircraft mechanic I can go into detail on a different thread)) the 3. 07 gearing is higher than most other trucks so less wear and tear there as well... I love my truck so much that even if I could afford something else, I wouldn't switch it out for any other at this time, it is so simple and reliable AND CHEAP. I purchased mine a year ago for 5K at a dealer, with 145,000 on the clock, near perfect interior, immaculate engine compartment, new paint, electric trailer brakes, no mods on engine or drivetrain... If mine withstood this condition in the stock setting for 145,00 (now almost 165,000) and was still this nice, rest assure that yours will bring you many more years of trouble free stock performance, at least yours in intercooled. get yourself a 16cm turbo exhaust housing for decreased turbo lag, a BHAF and gauges, and you're good to go, and go and go. You will spend many many hours on these forums doing searches and reading past topics. All the guys on here are honest and are of all experiences, and won't hesitate to help.



All in all, give it some time to grow on you, realize the nature of the cummins in this setup, and it's limitations or lacktherof and WOT it all day long . I know, I know, I too would like a CAT c16 engine that you can lug in any gear down to 1000 RPM all day long that has variable valve timing, Twins, and common rail as stock equipment(read the CAT webpage for details), OH WELL!

Good luck!

 

[Sasquach]

thanks all for the help and welcome. i used to be a ford guy, and the related sites were full of politics and bs. im glad to see tdr is so helpful and informative, as my exp with diesels is limited. chuck

 

[DDHansen]

US Gear

Well, its over three years since the last post, does anyone have any other experience w the US Gear product?



I am almost ready to plunk down my $ but since I have a NP205 (which they claim they don't interface to - but I have seen at least two vendors supplying installations). I have been asking them questions. So far they are responsive - but a bit slow.



thanks for your input



Dennis

 

[Pavemen]

I've got the US Gear underdrive behind my NV4500 on my 3500. Its great. Splitting gears is awesome for towing. I have 3. 54's in the rear end so underdriver gives me 4. 46 in effective ratio.

At times I wish I had 4. 56's or 4. 88's and an overdrive instead, but I'll take what its got (bought truck used with the unit installed already). At least in that case, you could run in 4th+overdrive and be like in 5th gear, without the load on the 5th gear nut.

Anyway, its a good unit so far. A bit loud on the disengage at lower speeds but not really noticeable at higher speeds.

 

[DDHansen]

US Gear Overdrive

Pavemen



thanks for the reply! Will post my progress w the unit as I go.





Dennis

 

[Loren]

I've got the US Gear underdrive behind my NV4500 on my 3500. Its great. Splitting gears is awesome for towing. I have 3. 54's in the rear end so underdriver gives me 4. 46 in effective ratio.



At times I wish I had 4. 56's or 4. 88's and an overdrive instead, but I'll take what its got (bought truck used with the unit installed already). At least in that case, you could run in 4th+overdrive and be like in 5th gear, without the load on the 5th gear nut.

Here's how to decide whether to order an overdrive or an underdrive: If you want a gear lower than first, order an underdrive. If you want a gear higher than fifth (or sixth) order an overdrive.



Both units allow splitting the gears and the only difference is whether you get a higher high or a lower low.



Actually, that's not entirely true, since an underdrive unit will reduce the load on the clutch and main transmission for the same torque at the wheels, while an overdrive will increase that load. In spite of this, I think that most drivers will be best served with an overdrive.



Loren