Michael Posted September 15, 2000 Share Posted September 15, 2000 Well, I just drove my rat-powered 280Z for the first time (see post under "Chevy V8" topic for more details). The car has a Doug Nash 5-speed. Even after reworking the shift linkages and oiling the shifter mechanicals, the thing is still incredibly notchy to shift. It's so bad that more time is spent on the 1-2 shift than under power in 1st or 2nd gear. There is essentially no feel for neutral, and telling 3rd and 5th apart is very difficult. Fortunately, the engine has so much torque that with street tires, 3rd and 5th gears are indestinguishable. So, to anyone contemplating the Doug Nash or Richmond transmission, let me caution them to beware of the king of notch. Perhaps with time this thing will smooth out.... I hope! But at least the clutch is light and smooth (3/4" Tilton master cylinder, McLeod hydraulic throwout bearing, Centerforce Dual-Friction clutch). Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 15, 2000 Share Posted September 15, 2000 Michael, was your Richmond new when you got it? I was just wondering if someone had worn out the synchros before you got it. Also, did your mechanic check for input shaft alignment (offset and angle) into the pilot bushing? I can't remember if you have an aftermarket bellhousing, but this can be a problem with the aftermarket bellhousings. The tolerances on offset of the register hole for the bearing retainer in the bellhousing is like 0.005" and there is a parallelism and flatness tolerance as well. These measurements being out can cause big problems with shift quality, since the input shaft will be side loaded on the pilot bushing and it will tend to keep it turning even with the clutch depressed. Quote Link to comment Share on other sites More sharing options...
Guest mattrp Posted September 15, 2000 Share Posted September 15, 2000 Yeah, Keep us posted on this tranny thing. I am seriously considering a doug nash or richmond and had not heard this before. I want in the order of 450 hp and 500+ torque when I finish with with either a blower or supercharged injection system, and I assumed those were the only trannys available to handle that. Besides, I like the idea that I can dump the clutch whwnever and never worry about destroying my tranny like I have to worry about with this stupid t5. Matt 72 500Z Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 16, 2000 Share Posted September 16, 2000 Matt - why not the T56? Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted September 16, 2000 Share Posted September 16, 2000 Matt, I agree with Pete - why not the T56? 6 gears with a .5 overdrive is pretty schweet. These puppies go into Vipers (slight mods to them) and handle bigtime HP in those cars. They can be gotten in junkyards and if they DO fail there are bound to be more people around that have the skills to fix them! Doesn't the Nash 5speed have a 1:1 5th gear? With 3.70 gears that could get old in a hurry.... Quote Link to comment Share on other sites More sharing options...
Guest mattrp Posted September 16, 2000 Share Posted September 16, 2000 I'm still contemplating the possibilities, and since none of this will happen until my first year of college is done with, I've got some time. Yes the T56 is a valid option, but it does not have anywhere near the power handling ability. I am seriously considering a centrifugal supercharging system like they run on the 5.0 l mustangs or one hell of a big blower on 383 (the largest holley, or weiland) and I like the idea of being able to drop the clutch whenever. Is the T56 that tough that it will not be my most expensive weak link in a 450 - 500+ hp and torque car. My local machine shop bud is a alchol and nitro funny car drag racer and runs the doug nash and richmond trannies and suggested them as an option. He claims he can pick one up for me for $2400. I'm open to suggestions. I just want to blow my diff up and throw half shafts before I even worry about transmission damage. I rebuilt my T5 without a shop manual and a long tedious process that was. One more gear and things could really get ugly. I do like the idea of that super low overdrive though. Hmm, choices. Gotta get the cage, and blower to blow my current tranny up before I consider the next one. Hehehe. Matt 72 500Z Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 17, 2000 Share Posted September 17, 2000 There are 777 hp Vipers running around with T56s. I don't know if they've been upgraded to handle that though. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 19, 2000 Share Posted September 19, 2000 quote: Originally posted by Michael: Well, I just drove my rat-powered 280Z for the first time (see post under "Chevy V8" topic for more details). The car has a Doug Nash 5-speed. Even after reworking the shift linkages and oiling the shifter mechanicals, the thing is still incredibly notchy to shift. It's so bad that more time is spent on the 1-2 shift than under power in 1st or 2nd gear. There is essentially no feel for neutral, and telling 3rd and 5th apart is very difficult. Fortunately, the engine has so much torque that with street tires, 3rd and 5th gears are indestinguishable. So, to anyone contemplating the Doug Nash or Richmond transmission, let me caution them to beware of the king of notch. Perhaps with time this thing will smooth out.... I hope! But at least the clutch is light and smooth (3/4" Tilton master cylinder, McLeod hydraulic throwout bearing, Centerforce Dual-Friction clutch). My brother had the same problem. He switched from a hurst to a long shifter and that cured it. The long shifter is expensive but I hear tht it work very well. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted September 19, 2000 Share Posted September 19, 2000 Vipers do have an upgrade or two - the one I'm most aware of has something to do with the shift forks being stronger. Looking through one of my latest Chevy geared mags I spotted much the same question with regards to the T56. The response back from the editor was that they knew of at least one T56 in an aplication that was WAY above it's rated torque and HP. The T56 isn't indestructable for sure but it's likely to be a damned sight stronger than the U-joints in a Datsun rear at least. Remember the lighter weight of our cars too. These transmissions are designed for heavier cars - our lighter weight helps them live under even more strenuous loads. I can't say for sure that the more race oriented transmissions wouldn't hold up better, in fact I'm pretty sure they would. Howver they've got a higher price tag on them, race oriented gear ratios, fitment issues, and shift quality issues. That's alot of issues! Take a look at one of those long shifters with arms everywhere and then look at your trans tunnel - yikes! I'm putting a T56 behind a 383 SBC that's supposed to make 450+hp and I'm honestly not worried about the trans. Heh, for that matter I'll be running the old clutch that came with the trans until it dies FWIW hi-po Mustang guys are starting to look in to the T56 now, the shop I deal with has installed at least three of them with no failures - yet. You've got time so wait and see how the rest of us fare and I'll keep an eye on the Mustang guys to see if they run into issues. P.S. %%$!! please delete th epost above this one - I can't! [This message has been edited by BLKMGK (edited September 19, 2000).] Quote Link to comment Share on other sites More sharing options...
pparaska Posted September 19, 2000 Share Posted September 19, 2000 BLKMGK, I deleted it. Yeah, I've seen mention of the better (cast iron?) shift forks in some of the Chevy mags. I wonder if this is any easy upgrade. Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted September 19, 2000 Share Posted September 19, 2000 Thanks! as to the shift forks - I wonder if it's even worth upgrading. On the T5s there were issues with bent forks from people powershifting and overtravelling the stops. Better shifters with lock bolts stopped this problem. If the Viper has stronger forks becasue of this I'd think a better shifter would be the easier fix (shrug). Does the Viper have different ratios? A taller 1st gear would increase the torque capacity as the multiplication wouldn't be as strong. This is partly what the T5 did to increase it's strength. For us a taller 1st wouldn't be bad I'll worry about it if I ever manage to break the box or if my used unit turns out to need rebuilding (shiver)... Quote Link to comment Share on other sites More sharing options...
Michael Posted September 21, 2000 Author Share Posted September 21, 2000 The transmission that I was talking about (Doug Nash 5-speed) was purchased used, with a claimed 20,000 miles on it. The application was in a V-12 Jaguar, and the seller claimed that he was selling it only because he upgraded to a six-speed Richmond (no overdrive in a Jaguar is even sillier than no overdrive in a Datsun). Anyway, what I bought almost certainly inferior to a brand new unit. But I only paid $750, with the shifter. The transmission also makes a dull "whirring" noise when going in reverse - and only in reverse. Quote Link to comment Share on other sites More sharing options...
Guest Anonymous Posted September 21, 2000 Share Posted September 21, 2000 quote: Doesn't the Nash 5speed have a 1:1 5th gear? With 3.70 gears that could get old in a hurry.... [/b] Yeah 1:1 fifth. It has a fairly deep first gear (3.28) (for a non-overdrive transmission). It allows you to run numerically low rear end gears (2.70's, 2.90's, low three's) and still get a decent launch in first and a decently spaced gear ratio throughout. The ratio's continue 2nd=2.13, 3rd=1.57, 4th=1.24, 5th=1.00.). The use of such high gearing works as a overdrive somewhat. I didn't know they were that notchy though, and yeah with a car geared in the 3.70's, it would be about as pleasant as cooking bacon naked (well perhaps a little more pleasant, depends what your into... ). Lone Quote Link to comment Share on other sites More sharing options...
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