Doug Nash & Richmond

[corvette66]

I will soon be finishing my supercharged 86 project, originally was going to have the 502 BB, but decided to stoke a 350 .030 now 383ci. I really don't want to re-install the 4+3 doug nash trani. (I know this involves fabrication) I don't know how much HP the 4+3 can handle. Anyway I noticed recently that the Richmond T-10 4 speed looks the same as the 4+3 DN. Other than the OD unit of course. So I got to thinking, there is a lot of Doug Nash bashing going on out there. I have had my share of 4+3 problems as well as everyone else who owns one, but it's only the Overdrive unit that ever seems to give anyone any problems. The T-10 it'self seems to be a mechanically sound unit. So Is there any difference between the Richmond T-10 and the Doug Nash T-10? If they are both the same unit, (since they both are called the T-10) why does the Doug Nash lack the Richmond logo, cause I assume it's manufactured by Richmond.

So basically my question is....are they both the same unit? And could the doug nash handle they same abuse the richmond modle can?

If I could I would just eliminate my OD unit and attach the same tail shaft the Richmond has, but the Doug Nash OD unit has the mounts for the driveline support beam. How do the 6 speed tranys in the 89 and newer models hook up to the driveline support? I noticed they corvette 6 speeds do not have the driveline support mount holes.

 

[Ken]

Same transmission - Richmond bought out Doug Nash's interest in the trans a few years ago.

Doug Nash, when he was building the 4+3, in turn used the old Borg Warner Super T-10 as that transmission.

 

[WhalePirot]

Here we go again!

My stock Super T-10 had many cracks on the gear teeth, especially in 2nd. When I had mine redone, there were very few options for stronger gears for it. Richmond MAY have changed that. I'd surely call. The stock unit is weakest in first gear, and I was told it was rated at 225 lb.ft. Changing gear sets, as I did, supposedly gave me another 100 lb.ft.

The 4+3 uses a shaft from the O/D, which penetrates the T-10 case and holds the reverse gear, so there's a bit more to it than the beam mount.

The overdrive is actually quite strong and, I was told, capable of more torque than the Super T-10. Mine was done by Paul, in Boca Raton, before he sold out. He built all the overdrives for Callaway and said I'd never break the unit.

So far, the unit works great with my 406! I was told that some do not like the noisy Richie 6-speed.

 

[rrubel]

Not that I'm doubting you, but how is it possible that first gear can only handle 225 lb-ft of torque, when the L98 puts out 330? I'd think we'd be breaking gears right and left the first time anyone hit the dragstrip.
[RICHR]

 

[corvette66]

doiurhbnsiudrygncsiur

It would prolly be in my best interest to replace the 4+3 I take it. My 383 will probaly have 400+ ft lbs, add on top of that a 671 Weiand. Is there any good direct replacements for the stock differential?

I find it odd that richmond wanted to buy out the Doug nash... Other than for supply'n a replacement for the Borg Warner set ups, and Doug Nash units.

So do the 89 and newer vettes (6 speeds) have the same driveline support, or does it hook up to the 6 speed transmissions in a different manor than the 4+3? If I have to add the 6 speed I will have to do something with the driveline support. I read the procedure for installing a 6 speed in a mid 80's vette from the Richmond web site. But I don't recall it saying anything about the support.

 

[WhalePirot]

how is it possible that first gear can only handle 225 lb-ft of torque

Rich, just what I was told by my builder. Could it be that I got some bad poop in the hot rod circle?...LOL

It seems to be just fine with the 500+ going thru it now. I stayed with the Nash as I had already spent $1500 on the O/D.

My next choice, should this break, is either a Richie 6 or a strong automatic.

Richmond makes a 6er with a tailpiece that fits our cars. It costs a bit more. One shop told me that the Richie was noisier and some customers had them removed. Some have said here that the noise eases with break-in.

The Dana 44 is larger and stronger than a 36. Lots has been said elsewhere on this one. Either is the only choice I am aware of, given the rear cover/crossmember piece. That is, unless you want a customized rear end (solid axle?).

 

[Ken]

I like my ROD 6-speed.

 

[corvette66]

cglkjsahrdlkgjsh

"Richmond makes a tail piece that fits our cars" So I could buy any richmond 6 speed and just buy the Vette style tail piece? That would be perfect.

I don't want to sound like an idiot, but what kind of differential is in our cars, well my 86 anyway? Is it a GM design. or was it designed by another company? Can I install the Dana 44 gears in my differential case? would my casing be stong enough to handle over 600HP? Or does Dana make a replacement differential and case that would hook up to my car?

How tough is our stock driveshafts? They relatively strong?

thanx guys

 

[bossvette]

I like my Tremec TKO 5-speed OD and it is about $1000 cheaper then the ROD

 

[corvette66]

A Tremec 5 speed? Do you have any sites with a picture of it by chance?

 

[bossvette]

A Tremec 5 speed? Do you have any sites with a picture of it by chance?

http://www.fortesparts.com/

is where I bought mine back in 2000 before the offset shifter, I dont know about where the shifter comes in a C-4
Here are some pictures of mine in no particular order http://www.villagephotos.com/pubbrowse.asp?selected=558419

 

[corvette66]

Looks like a decent trani, wonder if they make a tailpiece to hook it up to a C4.

 

[rrubel]

If you've got a 4+3, then you have the Dana 44 unit already. It's stronger (one more bolt, IIRC, and thicker housing) than the D36 that autos got. You can change the ring and pinion gear to a lower ratio for better acceleration (I think I got that right). However, for a stock engine that's pretty much a waste because we have no high-end power, and all the gearing would do is get you out of your power band faster...
[RICHR]

 

[corvette66]

Bonus

So in other words, my rear end should be able to handle what ever I through at it?

I'm try'n to get some pictures of my car up on here, but I can't seem to figure out how to get'em in.

 

[bossvette]

So in other words, my rear end should be able to handle what ever I through at it?

I'm try'n to get some pictures of my car up on here, but I can't seem to figure out how to get'em in.

this is how I do it
To post pictures so they show up in your post first you need to have the pictures on the web I use a photo hosting service:
http://www.villagephotos.com/index.asp
is one of many. Click on the IMG button in the area above where you type your posting Then you copy the URL of the photo to the Dialog box (be sure there is only one http) by using the links under the photos in blue, just click where it says "copy URL to clipboard" in blue.

Your picture should show up in your post

you can also host pictures in the members gallery if you are a supporting member, but I have not figured that one out yet:L

 

[wilezcoyote]

C-4 6-speed T-56 bolt in kit

There's a shop called Keisler Auto in Knoxville Tn, that's got an ad in July '04 issue of Corvette Fever. Their kit supposedly,
* Replaces the 4+3 or automatic
* Is based on new T56 6 speed
* Custom fit for original look
* Retains the stock shifter location for all Corvette Applications

Their web site is www.keislerauto.com

I emailed them last week for info and a $$price$$. I haven't got a response yet or my spam filter ate it.

There was a write up in one of their C3 kits in another magazine recently.

 

[rrubel]

Well, being able to handle ANYTHING you throw at a Dana44 is an oversimplification. It'll take a lot, but isn't indestructable. They appear to be the unit of choice for rockcrawling 4x4s, so they'll take a lot of abuse, but I can't find a listing of how much torque they'll reliably handle.
[RICHR]

 

[Hib Halverson]

The 4+3 (we lovingly call it the "Doug Nash"), used from 1984 to 1988 was one of the warranty disasters which befell Corvette in the early 80s. Actually, the tranmission section of the Doug Nash, a beefed-up version of the Warner "Super T10" used on Corvette from 1973 to 1981, was a fine transmission. It was the overdrive part of the 4+3 which was a POS.

That O.D. will not be reliable and durable behind a 502 or a supercharged 383 and the transmission section might be iffy.

Ok.
Now the story...

When Borg-Warner exited the four-speed manual transmission business about 1980, it sold the tooling and the rights to its four-speed (the Super T10) to Doug Nash (actually the DNE Corp). DNE, had obtained the contract from GM to build the 4+3s and undertook a development program to strengthen the transmission then add (big mistake) a single-speed, electro-hydraulic overdrive which was derived from an earlier O.D. Doug Nash sold to the RV market.

This product--mainly the warranty claims and obscenely poor QRD---caused DNE to loose the GM contract and that contributed greatly to the DNE Corporation's bankruptcy in the mid-80s.

After DNE declared BK, Richmond Gear purchased the rights to virtually all of DNE's manual transmissions, which at the time, were the Super T10 (now called the Richmond T10) the street five-speed and road race five-speed. Richmond has since made a ton of improvements to those products and added a six-speed derived from the five-speed.

Now, to your question about alternatives to the Doug Nash...you have two easy (but not necesarily inexpensive) choices: you can update the car with an axle ratio change and a ZF S6-40 six-speed (the OE C4 man. from 89-96) or you can buy Richmond Gear's 84-87 update kit which includes a Richmond six-speed and everything you need to bolt it into an early C4 manual. The former will net you the smoothest shifting and the strongest transmission but will probably be pretty expensive as you'll have to change the axle ratio, too. The latter will be less expensive because you retain your 3.07s but the Richmond doesn't shift quite as nicely and, while certainly strong enough for a 383 and even some 502s, is not quite at robust as the ZF.

You also might consider the Kiesler conversion of the T56 (which is briefly discussed above) but I think reliability/durability of that might be marginal behind a supercharged engine unless Kiesler uses the Dodge Viper version of the T56 rather than the Chevy Camaro version.

 

[corvette66]

Thanx Hib for all the info, thats what I been wondering. We can all thank doug for going under, No more headaches. The first time I ever worked on that OD, I was to the point of going MAD. ad I was tossing tools all accross the room, damn near threw everthing within reach. And I'm not a violent man. Wish I could have gott'n it on tape.
But you are saying that the most durable trani would be the ZF, even ovet the Richmond. I still got some time yet before I have to make a choice.

I'll think I'll leave the Dana 44 in for a while. Not sure if I really want to spend a load of money on this vette. I spent a lot on the motor already , but I can always swap it into another vette. I have 2 86's I should get rid of them both before I go nuts. It's just that they handle so well, I would hate to replace them.

 

[Ken]

Thanks Hib. You do a much better job of explaining things, but then, that's why you're a paid "Technical Writer for Internet & Print Media." :L

Seriously, thanks for explaining that.