2spd Over Drive Install w/Pics

[vtblazer]

Installed an older style Doug Nash 2spd overdrive transmission in my 72 K20 4x4 in two nights, okay, two long nights. Took two of us about 12hrs total.

Things that had to happen:
1) Had a machine shop make up a stubby slip joint. 6-3/4" open/installed.
2) Had same shop shorten a drive line 29"
3) Earlier in the year when I had new flows put on, I had the guy tip them as much as possible for this application.
4) Scratch build a mount system.
5) Installed a two speed mushroom switch just like the big trucks use for their 2spd axles.

I ended up using a grease-able front bushing set I had from ORD for the rubber mounts, worked slick. Just halved the mounts and continued on.

Some quick pics...

[vtblazer]

Things went along pretty good, it seemed to tuck up nice and alignment was working out.

Hit the bare metal areas with some SEM for protection until I have a chance to get everything finished. Good old rattle can job.

[vtblazer]

More yet...

We made the mounting system so if ever needed, it could be dropped and removed easily. As easily as a tranny can be removed anyway.
I kept the original drive line intact and it will be with me on road trips just in case the O/D unit quits working. At least then, I won't be stranded.

The good is that it works/shifts and certainly lowers my engine rpm's.

The bad is that it needs to come back out...ugh.
It's got either a bad bearing, busted gear or something going on.

Haven't had a chance to hit the highway yet due to issue's listed above but I'll post up when I do.

I'm pleased with they way you can hardly even notice it, until you really look.

[knsmodels]

Nice job.....have you taken it on its maiden voyage yet with the new over drive??? What will this do for your cruising RPM's and increase in gas mileage??

Disreguard.....didnt see your last post......Nice job though...

[TP from Cntl PA]

I wish they made a 3 spd version of those old Nash's(Maybe they did but I never seen one).................I know I wish I had one with an underdrive for starting out loads on a grade.

I wanted to stuff a 3 spd Brownie in mine.................I doubt it would have fit so I didn't bother.

Anyhow, nice work.

[biglou55]

Kurt awesome job. It does hurt when you have to take it out again. been there done that. Keep that up and you will have to put a mechanic on retainer as well as your body man. Keep us informed. Your crazy friend Lou. H.

[Yukon Jack]

Looks like you did a great job getting it in there. Sure shortens up that rear shaft!

[shelby987]

I was wondering about a brownie setup too....these are the units built by watson/dana/spicer/brown lupe right? (I have been unable to find ANY information on any of these units.....does anyone know anything about them?).

VTblazer, AWESOME job.....I couldn't figure out why the driveshaft was SOO short until I looked at additional pics, I just figured it would bolt to the output side of the transfer case like the gear venders....I like this way better....tucks that drive shaft up there nicely too...what angle did you end up with on the driveshaft when you were done?

[farside847]

Hey, very cool! Keep us updated on how it works!

Is it a manual shift? How did you rig the control?

[vtblazer]

Originally Posted by shelby987

what angle did you end up with on the driveshaft when you were done?

During final fit up, we measured the rear axle yolk angle to be 5 degrees sitting on the ground under it's own weight.
Matched the 2nd tranny output @ 5 degrees as well.

Pulled it out by myself in the driveway in about 15 minutes.

[TP from Cntl PA]

Originally Posted by shelby987

I was wondering about a brownie setup too....these are the units built by watson/dana/spicer/brown lupe right? (I have been unable to find ANY information on any of these units.....does anyone know anything about them?).

I am talking about the over/under Brownies used in 2 and 1/2 ton trucks.........They are big and bulky, but I like having overkill.

I have seen an over and direct drive box that Dana made.........It goes inbetween the bell housing and transmission on manual trucks and is shifted with another stick in the cab. Looked pretty neat, but I never met anyone that used on in a pickup. I seen one on ebay and I shoulda bought it, but thought it would still be there when I got home, but someone hit the buy it now inbetween when I was at work and home. Works on the same principle as the setup I threw togther here at home with the sag 3 spds.

[GMan69]

And to think, I was feelin' so proud of installing my front sway bar. Child's play compared to what you've done.
Great job, and I'm sure you'll get the bugs worked out soon.

[Robert1970C20rstbukt]

Very cool! Hope you get it fixed.

There was a 1960's Chevy C50 dumptruck at the junkyard here that had one of those over/underdrive units. The tag said Dana/Spicer on it and it was mated to a SM420 4 speed. It had Under, Neutral, Over, and Direct, I think that's what it looked like on the shift knob. I knew I should have asked how much he wanted for it but the truck got crushed before I even remembered to ask about it. It sucks 'cause that truck just needed some carb and brake work and it could've been a good truck.

[Chris H]

That is some great fabrication work! Thank you for the great pics and do keep this thread updated when you get it back together.
I have the TH400 version of the same DNE2 overdrive that will be going in my 72 C30, so very interested in your results.

[shelby987]

VTblazer, out of curiousity, what was the final cost for the stubby slip joint and having your driveshaft shortened? I have an eaton rearend with 4.56's....and while 4.10's will help, the cost of putting new 4.10's in the front and rear will likely cost as much as getting a setup like this.....just trying to figure out what the total cost of everything but the unit itself will come to....

yes, yes, for those that will chime in with "$1,000 buys a lot of gas"....I have this to say .....it doesn't buy as much as it used to, and at almost 4,000 rpm on the highway.....it won't take long before the replacement of some worn out parts will add up to that same $1,000....

[vtblazer]

Originally Posted by shelby987

yes, yes, for those that will chime in with "$1,000 buys a lot of gas"....I have this to say .....it doesn't buy as much as it used to, and at almost 4,000 rpm on the highway.....it won't take long before the replacement of some worn out parts will add up to that same $1,000....

EXACTLY!!

My reasoning is not for gas mileage but for parts preservation.
I'm not big on my 396 turning 3K (and then some) for hours at a time...

Stubby shaft was quoted @ $200 but turned out to be $300 with the u-joint included.

[shelby987]

how about the driveshaft resize?
Did you look into possibly using a stock trans. cross member from a 2wd in place of your setup? (don't have access to as many tools as I would like, and trying to find some steps that save on fabrication).
Thanks

[vtblazer]

Originally Posted by shelby987

how about the driveshaft resize?
Did you look into possibly using a stock trans. cross member from a 2wd in place of your setup? (don't have access to as many tools as I would like, and trying to find some steps that save on fabrication).
Thanks

No charge for the drive line shortening.
The guy missed the quote of the stubby shaft so bad he cut down the drive line at no charge. Would of been $50 bucks though had he charged for it.
To have it balanced was another $60.

Didn't look into any other mounting option's.
Another x-member might be a good idea/work but you'll still need to fab up a way to attatch it to the over drive itself.
Does yours have any mounting points on it?

[Chris H]

Any progress on this?

[69k5]

how much did it drop your rpm's?

would it fit in a blazer?

[vtblazer]

Okay, here's the good and the bad, yes there's still some bad.

Had to spend an additional $350.00 @ the transmission shop but the guy knew what he was doing and installed a new motor within that price.

Turned out that a previous owner installed a 1/4" plate for mounting purposes in between the cases and in doing so, blocked off the oil passage to the front input bearing.
^^NOTE ON THIS^^ neither owners prior to myself had used this unit, therefore they had no way of knowing about these issues.
No harm, no fowl. I'll do business/trade with both given the chance.
Both board members both contacted me when they read the original thread.
Nuff said on that.

So is it perfect? NO.
Drive line angles are off. Getting some vibration.
The unit will be removed and reinstalled utilizing the new drive line info I've since learned about.

Does it work? Have I tried it on the interstate? YES.
It works pretty slick, once working correctly it will be a nice mod.
@ a 20% overdrive, it lowers my highway rpm's by aprox. 1K - if I can trust the factory tach. I'm in the process of installing a known to be 'accurate' after market tach.
I can now keep up with traffic without worrying about trashing my big block.

[tnblazerk5]

are you going to put a skid plate under it ?

looks like a great job ya did there i like it and may have to go find me one and try that

[vtblazer]

Originally Posted by tnblazerk5

are you going to put a skid plate under it ?

At some point maybe but this truck doesn't really go off-road so the immediate need isn't there.
Most likely though as time and cash allow.