US Gear OD noisy?

[Gary - K7GLD]

I have the US Gear OD unit installed on my truck (see sig below), and with over 100,000 miles on the truck, am hearing a faint gear or bearing growl/rumble at moderate speeds under light load. The noise IS faint, but noticeable, and disappears when you let up on the accellerator or are coasting - it also is reduced somewhat under full load. I changed the gear lube in it today, and can see traces of fine microscopic brass "sheen" suspended in the old lube, but not a whole lot, and pretty much typical of normal transmission drainings - no ferrous meterials were detectable (magnet test).

Tho' the manufacturer specifies 90wt gear oil - it takes a quart to fill, I used multigrade 80/140 for this change, with about a quarter bottle of STP added - this SEEMS to have quieted the noise down, but need to drive it more to be sure - otherwise, can't be REAL certain if the problem (if any!) IS in the OD, or the A/T transmission's planetary - it's pretty hard sometimes to accurately pinpoint the origin of noises like this...

SOOOoo - any other hi-mileage US Gear owners out there with similar noises? Or suggestions? Perhaps this is just normal for the mileage on the drivetrain, and nothing to be concerned about?

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http://community. webshots.com/user/davison71 Early '91 250, 727 AT, 307 rear... Banks Stinger exhaust, intercooler... US Gear OD... Tweaked pump, upgraded radiator... MORE than a match for every new PS Ford encountered so far...

"Dura" WHAT? NOW I know where all those recycled beer cans go...

[This message has been edited by Gary - KJ6Q (edited 04-05-2001). ]

 

[Powder Extreme]

I had a US Gear in my old pickup, it whined most of the time and gradually got worse. When I finally decidided it was to noisy, we tore it down and it basically needed a total rebuild. I was told that the unit needed to have the oil changed every 30,000 miles. Mine like yours changed in pitch and intensity depending on the load and how much throttle.

Jerry

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2001 Quad Cab Dually, ETH, SLT Plus, Isspro Pyro & 50lb Boost, EZ Box, 275 injectors, Banks Power Pack, custom "Scotty style" airbox, amsoil dual bypass, 4" DD exhaust.

'94 SLT 4x4 V-10, straight pipes and a K&N (can't find anything else

 

[Turbo Thom]

Gary:
I have 194K on my truck with 82K on the US Gear OV unit. Mine also is starting to whine and also does not seem to shift as crisp as it once did. I use Amsoil S 2000 75W-90 in mine and up till 3,000 miles back had no noise or problems at all. If that heaver lube does better I'll order some Monday. I thought the noise was the NV4500. My mech. said it was the OV unit. Live and learn.
Good luck.
Preston

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96 3500, Black SLT, 5 speed, turbo diesel, , with US Gear overdrive, Rhino liner, Reese 15,000 lb. fifth wheel hitch, US Gear de-celarator exhaust brake, muffler elimination kit, Amsoil lub. , Mag-hytec rear cover, dual-remote by-pass filters, and Roadmaster Active system, AutoMeter Pyro & boost, Primeloc

 

[Extreme1]

There was an article in a TDR not too long ago about a similar situation involving an auxilary transmission. His description was similar to yours. The writer (Jim L?) used a microphone device to pinpoint it. It wound up being the adapter shaft between the two transmissions.

I looked for a while but couldn't find it, anybody else?

I don't recall which type the US Gear is - gear reduction or sun & planetary, but don't get too gung-ho on changing the oil viscosity with the sun & planetary type unit.

They utilize a piston type oil pump to develop pressure to apply and hold a clutch face to get the ratio change. It is similar to what the Corvettes had with 4+3 trans which is similar to what European cars from the late sixties and 70s used. I don't know about the newer units but the early versions were a bit picky about viscosity changes which would slow apply times and could contribute to overheating.

Of course, if yours is a gear reduction type, none of this applies.

STP, huh? #ad
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'94 3500 4x4, 210,000 miles, Never had a cat, Auto w/shift kit (thanks Dave G), 3. 54 Gears, TST #5 plate, 235-85-16s, Rancho 9000s w/remote, Isspro Gauges & Amsoil Air, Oil & Bypass Filters & Lubes, AWOL intake boot.
Punchlist: 14 cm Turbo Housing & 215 Injectors.
NRA member.
Blue Ribbon Coalition member.
"I am my own performance station"

 

[Gary - K7GLD]

The US Gear OD is a 2-gear planetary unit, for a 22% or so O/U ratio - uses no clutches or pressure pumps for lube distribution, but LOTS of thrust washers and needle bearings on all shafts. It DOES use a shift-fork arrangement to switch ratios that is electrically servo-driven, and gear sizes are nice and rugged for heavy usage. Not sure how the simple sleeve adapter between the main transmission and US Gear OD could create much problem or noise unless it was misaligned - but anything is possible - tho' in MY case, since the heavier gear lube stopped about 90% of the noise, seems obvious the problem was INSIDE the box.

I want to stress the fact that the noise WAS faint, but I pull a 5th wheel in the hills enough that I am wary of potential problems. ALSO, 4 years or so back, on a LONG trailer pull across the US and back, a loose speedometer attachment allowed lots of lube to be lost, and I didn't find out about it until we arrived home. No signs of ANY problems at that time, remaining lube was clean and metal-free, and OD unit was still operating normally and quietly - but who knows what damage MIGHT have ocurred waiting to surface later.

In MY book, the US Gear unit is a dandy, wouldn't be without it, and if/when needed, WILL have it rebuilt and reinstalled! #ad
#ad


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http://community. webshots.com/user/davison71 Early '91 250, 727 AT, 307 rear... Banks Stinger exhaust, intercooler... US Gear OD... Tweaked pump, upgraded radiator... MORE than a match for every new PS Ford encountered so far...

"Dura" WHAT? NOW I know where all those recycled beer cans go...

[This message has been edited by Gary - KJ6Q (edited 04-07-2001). ]

 

[Gary - K7GLD]

Thanks Jerry - I really think they spec too light-weight lube for these units, mine has quieted CONSIDERABLY since I refilled with the 80/140 multi-grade plus a little STP - Next time I'm under the truck, will try to squeeze in a little more STP...

How many miles on your OD unit at overhaul time, and was it light or heavy duty use?

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http://community. webshots.com/user/davison71 Early '91 250, 727 AT, 307 rear... Banks Stinger exhaust, intercooler... US Gear OD... Tweaked pump, upgraded radiator... MORE than a match for every new PS Ford encountered so far...

"Dura" WHAT? NOW I know where all those recycled beer cans go...

 

[Powder Extreme]

I had around 50-75k miles, hard use, lotta towing. I started off with synthetic in it, shifted hard and whined, much improved with the 80-140 which is what the mechanic said he puts in all of em.

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2001 Quad Cab Dually, ETH, SLT Plus, Isspro Pyro & 50lb Boost, EZ Box, 275 injectors, Banks Power Pack, custom "Scotty style" airbox, amsoil dual bypass, 4" DD exhaust, Ceramic clutch.

'94 SLT 4x4 V-10, straight pipes and a K&N (can't find anything else