US Gear Dual Range / Doug Nash Info

[Arthur Eckert]

My approach would probably be to machine a 'top hat' that would go over the OD of that and mate with the flat surface of the plate and either weld to or have screw to hold it to the plate. Probably could find a plastic cap or similiar that would do the same and not require machining. Find something that fits reasonably snuggly and slobber a bunch of hardening type RTV in there when you put it on and if you're lucky that will seal it and hold the cap on.

Unwise to weld directly to the 'button' as that is a pocket on the inside that support the shift fork shaft.

Gasket on the plate/body surface can either be made from gasket material or just use RTV.

That is actually a great idea thanks. I hadn't considered just finding a cap and RTVing it over the old one. Any idea how hot that should get? Aside from the exhaust being there. I am just thinking I could 3d print a cap but I am wondering how hot the exhaust will get in that area. I figured if I took off the plate I would end up with a new RTV gasket already. I was debating any modern JBweld type material as well. Not sure if thats what you meant by the hardening type of RTV?

 

[jaluhn83]

Shouldn't get too hot - mine I think would get up to about 250* oil temp, and that's on a 4wd with the t-case blocking almost all airflow over it. Having the exhaust right next to it is going to cause problems though. Definitely need a metal cap, pretty sure plastic would melt.

Hardening type RTV is the normal stuff you get at parts stores. Non-hardening (permetex #2 or similar) is something I use more commonly, hence the differentiation. Just like is sounds, the hardening type cures and turns into a solid, while non hardening stays in a somewhat tacky liquid state.

 

[Arthur Eckert]

So I maybe making this harder than it needs to be. The gearbox is only supposed to hold about a quart of fluid and I just drained it and got a solid quart and a half. So that is after whatever has leaked out as well as it was gushing out of the fill port. I am wondering if the input seal on the Dual Range has gone bad and is allowing ATF to over fill it. I have been puzzled and mulling this over since the fluid I put in it was green and its clearly ATF coming out and you cant really over fill them since it will just run out. Anyone have any idea if a new seal can be sourced and from where? I would hate to have to pull it all apart and leave it in pieces while I try to find one. I have what I believe is the part number from US Gears but as we all know they are long gone and this has been discontinued.

 

[jaluhn83]

Check back through this thread - I posted a bunch of part numbers but can't recall if I had seal PNs or not. If not, measure ID, OD & thickness and do some research - I'm sure there's an oil seal out there which will fit.

 

[Arthur Eckert]

Check back through this thread - I posted a bunch of part numbers but can't recall if I had seal PNs or not. If not, measure ID, OD & thickness and do some research - I'm sure there's an oil seal out there which will fit.

Fantastic and thanks.. Yes, you listed SKF 19611 as the input shaft seal. Measurements of that seal are 35x52x8. At least that gives me hope! Its drive-able now even if I want to keep it limited until I get this fixed. I just wanted to avoid having to tear it apart in the driveway and having it sit while I source parts. I had to do that with my Volvo since no one could get me the right drive shaft seal. My biggest fear was it was going to run dry but clearly that wont be the issue in the mean time.

 

[Chris Helton]

Keeping this post going...
I came across a US Gear Dual Range Overdrive, complete with the 4wd adaptor to bolt up between a T19 and BW 1345. It is going into my '86 F250 6.9 turbo. Only issues I found was the selector motor was fried, and that was easily replaced with a 4 Seasons motor for an Eaton 2 speed rear end. The OD did not come with any of the electronics, so I back dated it to the mechanical switch, also off an Eaton unit. So, she is basically set up like the original Doug Nash units. Super clean inside, and I will mount a selector switch on my shift lever so I can split easily. Now the million dollar question, which I can't seem to figure out. Is there a seal on the output shaft (going to the transfer case) or does the "system" rely on the transfer case seal, and gasket to prevent leakage or fluid mixing. I have found the part number and seal for a 2wd application, which WILL use a seal in front of the out put yoke. Towcat posted a pic years ago of a spare unit he had, which shows no seal, so I am hoping nothing goes in there, and she will rely on the paper gasket to prevent leakage. Pic included of the shaft and gasket.
Thanks!
CH

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[Black dawg]

Keeping this post going...
I came across a US Gear Dual Range Overdrive, complete with the 4wd adaptor to bolt up between a T19 and BW 1345. It is going into my '86 F250 6.9 turbo. Only issues I found was the selector motor was fried, and that was easily replaced with a 4 Seasons motor for an Eaton 2 speed rear end. The OD did not come with any of the electronics, so I back dated it to the mechanical switch, also off an Eaton unit. So, she is basically set up like the original Doug Nash units. Super clean inside, and I will mount a selector switch on my shift lever so I can split easily. Now the million dollar question, which I can't seem to figure out. Is there a seal on the output shaft (going to the transfer case) or does the "system" rely on the transfer case seal, and gasket to prevent leakage or fluid mixing. I have found the part number and seal for a 2wd application, which WILL use a seal in front of the out put yoke. Towcat posted a pic years ago of a spare unit he had, which shows no seal, so I am hoping nothing goes in there, and she will rely on the paper gasket to prevent leakage. Pic included of the shaft and gasket.
Thanks!
CH

You must be registered for see images attach

What was involved with putting the older switch in? The us gear electronics pretty much suck.

 

[Chris Helton]

Easy peasy. My top cover came with dimples where DNE mounted the internal limit switch. Drilled them out, hardware store for some insulators and socked it down. My internals mated up with the limit switch.

 

[Black dawg]

Thanks for the picture. As far as the seal, I have written down napa# 16871 for an output seal. Was given a parts number list for rebuilding one some time ago, dont know if that is accurate or not.

 

[Desertprep]

Wow! I am amazed to find this thread! I have a 1992 F150 with the 4.9 i6. Right now I have a T19 in it, a 4 speed. I would like to put a 5 speed in it, either the ZF 5 or the M5OD-2. When I saw this UD unit, I thought it would help me get to and around my property while pulling a trailer. My property is at the end of a few miles of unmaintained road. Found an np435 (from a 1990ish F150) with the UD attached to it - married to it. Originally it has an nv205 transfer case attached to it, but the seller already sold it. My questions: will the UD unit mate to either the ZF 5 or the M5OD-2 without an adapter? If it needs one, will it be difficult to get? I have a BW 1356 TC in my truck now. Is that going to bolt up without an adapter? or will I need to dig up an nv205? That part wouldn't be so bad, but the BW has a lower low gear. Any help will be appreciated.

 

[Black dawg]

If it was bolted to the back of a 4x4 t19, it will bolt to the zf or the m5. Avoid the m5od if you can.

 

[Richard Coyle]

Well you learn a new thing every day. I have a US gear NOS I got two years ago, it was from a Ford a C6 and has a Dodge adapter so I made my own adapters and mated it to a 4L80e.

Just a month ago I got what the seller claimed was a overdrive but it is a DN underdrive, I may have a dear shifter motor, and there is some gear play at the out put shaft...I am hoping to fix that possible by shiming it up.

I am thinking I like the motor limit control switch more that the US Gear timer. Good idea there.

So I am looking for anyone with parts for a underdrive...

Here comes the insane idea I have, I plan on adding to to the van so I have 4 in the 4L80, a 5ths to double overdrive AND a underdrive to help power all into a 3:08.

I am using a 4L80 tail housing from a unit that had a bid brake drum which have bearings instead of bushings and with sealed bearings will need no oil, can be mounted on the front giving it a u joint input yoke.

I call it 5 over and 5 under.

The engine is a 383 low RPM engine running a mild performance cam but with rhoards roller lifers give it a nice low torque and still has good power to 4500RPMs fed with 87 Camaro TPI intake, I am looking for 25/30MPG at 75/85MPH.

Here is a chart for the engine performance and the gearing

 

[Black dawg]

In my experience with gas motors and really tall gearing, it can actually work pretty well and get really good mpg...to about 70mph. After that just felt like wind resistance was too much for the lack of torque ( at diesel like rpm).
Was a very low 1500 2wd suburban with 350tbi 700r4 and 2.73 gearing.

 

[Richard Coyle]

This year I saw a person on eBay selling a under drive and seemed he had more from some place in CA. Anyone know where these are? I really would like to find someone with parts...or a whole unit at a reasonable price.

Rich

 

[Richard Coyle]

In my experience with gas motors and really tall gearing, it can actually work pretty well and get really good mpg...to about 70mph. After that just felt like wind resistance was too much for the lack of torque ( at diesel like rpm).
Was a very low 1500 2wd suburban with 350tbi 700r4 and 2.73 gearing.

That is why I built a strong 383, for more torque, and gearing that will keep my RPMS between 1500 and 2000RPMs. Your engine needs to be built for low RPM torque, so I now feel more sure it should work well up to say 85MPH. Plus my van is more areo that most stock vans.

I discovered this when I first drove the 93 on a road trip and found it was NOT pushed off the road by Big Rig's bow wakes, a problem I had with a 74 G20 and a 78 G20 which I drove all over the USA during the 80s and 90s.

The cosmetic Ground Effects WORKED OMG...

Rich