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The RVer's Open Forum / GENERAL RV DISCUSSIONS / US Gear OD Auxiliary Owner's Report

Robert Hiebert
User ID: 9056633 Jul 22nd 10:52 PM
Hi All,
For anyone considering an auxiliary transmission for their RV or tow vehicle, this
may be of some interest.
I have a ‘92 Winnebago Elante 33, on a Ford chassis. Living on the coast in
British Columbia, I do a fair amount of mountain driving and found I could use a few
more gears to keep the engine in the RPM range that I like to use, which is between about
1800 and 2400 RPM, give or take a couple of hundred.
I researched both US Gear and Gear Vendors. I liked the idea of the clutch
arrangement that GV has, but after considerable digging, I found out that they don’t
recommend use with an exhaust brake, which I have.
That left my only known option to be US Gear, which operates like a 2 speed rear
axle. Primitive “dog clutch” shifting arrangement, but I’ve driven trucks with 2 speeds
before, and thought I knew what to expect.
The installation was relatively straight forward, though I thought the instructions
could have been a bit more specific for the E4OD with driveshaft park brake application
that I have. Quality of construction seems to be reasonable, except I found some
aluminum machining filings in the void where the park brake bolts on. I didn’t tear the
unit down to check the gear case. Hope I won’t regret that.
Another minor complaint was that a couple of the OEM bolts to attach the brake
were too long to fit by the shifter housing. Supply of correctly sized bolts would have
been nice. Also, where the bolts seat, the casting was not machined, and the rounded
casting puts side stress on the heads. A bit disappointing.
As far as operation is concerned, the bad news first.
I had expected a “clunk” during shifts. Well, at low vehicle speeds, a “clunk” it is,
but at highway speeds, it’s more of a “crash”. Downright violent! Scary!
I have a custom controller on my transmission, and I have complete control over
gear selection and torque converter clutch application and release. I tried all sorts of
different techniques to try and minimize the transition shock, but the only thing, other
than low speed shifting, was to do as one contributor to the testimonials suggested, to
shift the transmission to neutral while shifting the auxiliary. That’s a drag, really helps
only minimally, and could be potentially dangerous to your health. I suspect that a manual
transmission application would not suffer from this quite as bad, because of the fact that
there is less rotating mass in the transmission to slow down or speed up, but the fact that
the shifts tend to be so rough, really discourages split shifting at speed, which is one of
the main reasons I bought the unit.
Another source of irritation, though fortunately minor, is the gear whine that some
people have reported. I found that in my installation, in overdrive, and moderate to heavy
loads, it emitted a high pitched gear whine, almost like a turbo whistle, from about 75
KPH to 85KPH. My coach has enough road and induction noise that it’s not a major
problem, but it is there, and for some, may be a consideration. Direct drive is completely
silent.
Now, the good news.
I had no illusion that use of the OD unit would increase my fuel mileage, contrary
to claims by US gear, which could be possible, or GV, which in my opinion, could be
considered as downright fraudulent.
I have a 5.13 :1 final drive. With the stock transmission, my cruising speed, about
95KMpH is about 2200 RPM. 4th over would put me about 1750 RPM. I didn’t think I
would be able to use it that much. Well, it turns out I can. Really helps with the engine
noise and be darned if it doesn’t help a bit with economy. I’ve only put about 2000 miles
on it so far, but I keep careful records, and so far, I’m up about 2%. This will depend a lot
on where and how you drive, but I didn’t expect any improvement, so that’s a bonus.
Also, it’s real nice to have those extra gears on long pulls, even if split shifting is
painful. If you’re pulling a long grade, you can pick the right combination, lock the
clutch, and settle back where you want to be.
Would GV be any better? Dunno.
Would I do it again? Probably. It’s pretty pricey, and not all that I hoped for, but
it’s nice to have those gears, and I’ll learn to live with it’s faults.

Hope this helps someone,
Robert

Butch
User ID: 2727884 Jul 23rd 2:48 PM
I have used the U.S. Gear and unloaded it for the very reasons Robert described. It was manual shift and sometimes was a real bear to ingage. one must let off the throttle to shift the unit. I used a unit very similar to the GearVendors, IF not the same unit. The unit I installed in 1974 was I "believe" a Laycock. The parts & pieces were made in the U.S. then shipped to Europe where all parts & pieces were assembled then shipped back to the U.S. This was a silky smooth unit. One had to watch the tach to know when it shifted in automatically at approximately 45 MPH. It could be shifted in or out at any speed with the hammer down, electronically by flipping a switch, or leave it on and it would shift automatically. I also switched out the Ring & Pinion at the same time I installed the "Laycock" from a 4.56 to a 4.88. Both together upped my overall 5 MPG to 8 MPG. I liked that... The ability to have it act as a gear spliter was what I was after. It performed that function beautifully, as did the manual shift unit once it got shifted. None of my rigs at this period had an exhaust brake though I can't see where that would interfere. But, since I didn't have one, I never asked either...I have driven other units with a GearVendors, and it seemed to perform exactly like my earlier unit. I've often wondered if it were the same unit with a different name...

Happy Motoring, Butch

Nancy Lake, Alaska

Barthbill
User ID: 0067194 Jul 26th 11:26 PM
You're right, Butch. The GV is the old Laycock (or Laycock de Normanville) overdrive unit fitted to many European and British autos. I had a Jag with a similar unit. Overly complex. There are several permutations, but all are pretty close. When I was a hot rodder, I always thought the old Borg Warner T85 had the most rugged and simple overdrive, but no one has adapted them to the TH400.

The US Gear unit is descended form a Doug Nash unit, which, I believe, is descended from a Ford top loader of some kind.

Richard
User ID: 8771373 Nov 12th 9:44 PM
Robert,

Tell me about you aftermarket E4OD controler.
Would it be a Baumann Engineering Controler?

Richard in Kansas City

Robert
User ID: 9056633 Jan 26th 12:12 AM
Hi Richard,
Sorry about the long delay, I haven't checked in here for a while. No, it's not the Baumann controller, but I had hoped to use his. It didn't do everything I wanted so I approached Karl Baumann about modifying it. He seemed receptive to the idea, but eventually just didn't return my correspondance, so I ended up designing and building my own.
Robert

Richard
User ID: 8771373 Jan 29th 5:23 PM
Robert,
Thanks for the response. I contacted Baumann about the possibility of an electronic transmission temperature guage. The sensor is already in the transmission and I know they already have the data to build such a device. They blew me off also.........If I knew the temperature/output relationship of the sensor, it shouldn't be to hard to build. Don't know why some one hasn't keyed in on the sensors in both the Ford & GM transmissions to display tranny temp. Would be a lot less messy to install than cutting into the pan or oil lines.
Richard

Robert
User ID: 9056633 Jan 29th 11:54 PM
Hi Richard,
If your only concern is a transmission temperature guage, I suspect it would be easier, less expensive, and a whole bunch simpler to just install an in line or in sump sender and off the shelf guage. The thermistor that is in the transmission solonoid pack is, to the best of my knowledge, the same as Ford uses for coolant and intake air temperature, so the same analog to digital tables can be used, if you are already into that level of signal processing. The thermistor resistance/temperature relationship values are published in the Ford Service manuals.
I'm surprised to hear that Baumann is still in business. Their website hasn't been updated for eons, not a good sign.
Regards,
Robert

Barthbill
User ID: 0067194 Feb 3rd 10:24 AM
As far as trans temp goes, many pans don't have a drain plug. A drain plug will make changing fluid easier. If you use the B&M drain plug, a 1/8 NPT sender can fit in it. The B&M drain does not require anything but a drill and a wrench.

Robert Hiebert User ID: 9056633	Jul 22nd 10:52 PM Hi All, For anyone considering an auxiliary transmission for their RV or tow vehicle, this may be of some interest. I have a ‘92 Winnebago Elante 33, on a Ford chassis. Living on the coast in British Columbia, I do a fair amount of mountain driving and found I could use a few more gears to keep the engine in the RPM range that I like to use, which is between about 1800 and 2400 RPM, give or take a couple of hundred. I researched both US Gear and Gear Vendors. I liked the idea of the clutch arrangement that GV has, but after considerable digging, I found out that they don’t recommend use with an exhaust brake, which I have. That left my only known option to be US Gear, which operates like a 2 speed rear axle. Primitive “dog clutch” shifting arrangement, but I’ve driven trucks with 2 speeds before, and thought I knew what to expect. The installation was relatively straight forward, though I thought the instructions could have been a bit more specific for the E4OD with driveshaft park brake application that I have. Quality of construction seems to be reasonable, except I found some aluminum machining filings in the void where the park brake bolts on. I didn’t tear the unit down to check the gear case. Hope I won’t regret that. Another minor complaint was that a couple of the OEM bolts to attach the brake were too long to fit by the shifter housing. Supply of correctly sized bolts would have been nice. Also, where the bolts seat, the casting was not machined, and the rounded casting puts side stress on the heads. A bit disappointing. As far as operation is concerned, the bad news first. I had expected a “clunk” during shifts. Well, at low vehicle speeds, a “clunk” it is, but at highway speeds, it’s more of a “crash”. Downright violent! Scary! I have a custom controller on my transmission, and I have complete control over gear selection and torque converter clutch application and release. I tried all sorts of different techniques to try and minimize the transition shock, but the only thing, other than low speed shifting, was to do as one contributor to the testimonials suggested, to shift the transmission to neutral while shifting the auxiliary. That’s a drag, really helps only minimally, and could be potentially dangerous to your health. I suspect that a manual transmission application would not suffer from this quite as bad, because of the fact that there is less rotating mass in the transmission to slow down or speed up, but the fact that the shifts tend to be so rough, really discourages split shifting at speed, which is one of the main reasons I bought the unit. Another source of irritation, though fortunately minor, is the gear whine that some people have reported. I found that in my installation, in overdrive, and moderate to heavy loads, it emitted a high pitched gear whine, almost like a turbo whistle, from about 75 KPH to 85KPH. My coach has enough road and induction noise that it’s not a major problem, but it is there, and for some, may be a consideration. Direct drive is completely silent. Now, the good news. I had no illusion that use of the OD unit would increase my fuel mileage, contrary to claims by US gear, which could be possible, or GV, which in my opinion, could be considered as downright fraudulent. I have a 5.13 :1 final drive. With the stock transmission, my cruising speed, about 95KMpH is about 2200 RPM. 4th over would put me about 1750 RPM. I didn’t think I would be able to use it that much. Well, it turns out I can. Really helps with the engine noise and be darned if it doesn’t help a bit with economy. I’ve only put about 2000 miles on it so far, but I keep careful records, and so far, I’m up about 2%. This will depend a lot on where and how you drive, but I didn’t expect any improvement, so that’s a bonus. Also, it’s real nice to have those extra gears on long pulls, even if split shifting is painful. If you’re pulling a long grade, you can pick the right combination, lock the clutch, and settle back where you want to be. Would GV be any better? Dunno. Would I do it again? Probably. It’s pretty pricey, and not all that I hoped for, but it’s nice to have those gears, and I’ll learn to live with it’s faults. Hope this helps someone, Robert
Butch User ID: 2727884	Jul 23rd 2:48 PM I have used the U.S. Gear and unloaded it for the very reasons Robert described. It was manual shift and sometimes was a real bear to ingage. one must let off the throttle to shift the unit. I used a unit very similar to the GearVendors, IF not the same unit. The unit I installed in 1974 was I "believe" a Laycock. The parts & pieces were made in the U.S. then shipped to Europe where all parts & pieces were assembled then shipped back to the U.S. This was a silky smooth unit. One had to watch the tach to know when it shifted in automatically at approximately 45 MPH. It could be shifted in or out at any speed with the hammer down, electronically by flipping a switch, or leave it on and it would shift automatically. I also switched out the Ring & Pinion at the same time I installed the "Laycock" from a 4.56 to a 4.88. Both together upped my overall 5 MPG to 8 MPG. I liked that... The ability to have it act as a gear spliter was what I was after. It performed that function beautifully, as did the manual shift unit once it got shifted. None of my rigs at this period had an exhaust brake though I can't see where that would interfere. But, since I didn't have one, I never asked either...I have driven other units with a GearVendors, and it seemed to perform exactly like my earlier unit. I've often wondered if it were the same unit with a different name... Happy Motoring, Butch Nancy Lake, Alaska
Barthbill User ID: 0067194	Jul 26th 11:26 PM You're right, Butch. The GV is the old Laycock (or Laycock de Normanville) overdrive unit fitted to many European and British autos. I had a Jag with a similar unit. Overly complex. There are several permutations, but all are pretty close. When I was a hot rodder, I always thought the old Borg Warner T85 had the most rugged and simple overdrive, but no one has adapted them to the TH400. The US Gear unit is descended form a Doug Nash unit, which, I believe, is descended from a Ford top loader of some kind.
Richard User ID: 8771373	Nov 12th 9:44 PM Robert, Tell me about you aftermarket E4OD controler. Would it be a Baumann Engineering Controler? Richard in Kansas City
Robert User ID: 9056633	Jan 26th 12:12 AM Hi Richard, Sorry about the long delay, I haven't checked in here for a while. No, it's not the Baumann controller, but I had hoped to use his. It didn't do everything I wanted so I approached Karl Baumann about modifying it. He seemed receptive to the idea, but eventually just didn't return my correspondance, so I ended up designing and building my own. Robert
Richard User ID: 8771373	Jan 29th 5:23 PM Robert, Thanks for the response. I contacted Baumann about the possibility of an electronic transmission temperature guage. The sensor is already in the transmission and I know they already have the data to build such a device. They blew me off also.........If I knew the temperature/output relationship of the sensor, it shouldn't be to hard to build. Don't know why some one hasn't keyed in on the sensors in both the Ford & GM transmissions to display tranny temp. Would be a lot less messy to install than cutting into the pan or oil lines. Richard
Robert User ID: 9056633	Jan 29th 11:54 PM Hi Richard, If your only concern is a transmission temperature guage, I suspect it would be easier, less expensive, and a whole bunch simpler to just install an in line or in sump sender and off the shelf guage. The thermistor that is in the transmission solonoid pack is, to the best of my knowledge, the same as Ford uses for coolant and intake air temperature, so the same analog to digital tables can be used, if you are already into that level of signal processing. The thermistor resistance/temperature relationship values are published in the Ford Service manuals. I'm surprised to hear that Baumann is still in business. Their website hasn't been updated for eons, not a good sign. Regards, Robert
Barthbill User ID: 0067194	Feb 3rd 10:24 AM As far as trans temp goes, many pans don't have a drain plug. A drain plug will make changing fluid easier. If you use the B&M drain plug, a 1/8 NPT sender can fit in it. The B&M drain does not require anything but a drill and a wrench.