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Doug Nash 5 Speed

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Old Jan 31, 2013 | 10:50 AM
  #1  
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Default Doug Nash 5 Speed

Hey all,

I'm looking at purchasing 1978 C3. What's stopped me from getting a C3 before is the lack of overdrive, and the regular highway trips I plan on making in it on Texas highways (70-75mph speed limit).

This owner claims that he's swapped out his transmission for a "Doug Nash 5 speed," but he isn't sure of the 5th gear ratio or the final drive ratio in the vehicle.

Is there anywhere I can go to find out what options were offered for fifth gear ratios on DN transmissions? I understand that there was a race version and a street version, and I'm assuming that this tranny is the latter. Car's two hours away, don't want to ride over to look at it for nothing.
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Old Jan 31, 2013 | 11:17 AM
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All Doug Nash 5 speed I've ever seen were 1:1 5th. Richmond Gear still sells them as well as 5 and 6 speed OD trans.
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Old Jan 31, 2013 | 11:30 AM
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Ask the guy to tell you what RPMs he's turning at 60 MPH in 4th and then in 5th. Then ask for the tire size and you should be able to figure out what ratio the OD is.
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Old Jan 31, 2013 | 11:56 AM
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I have a Richmond 5 speed in my '81 (same as a Doug nash) it has the 1:1 5th gear. the transmission is awesome. they have that M22 whine in gears 1-4. I have a 2.87 rear diff and the RPMs aren't bad at all. If the car has a 3.08 or numerically lower gear, I'd say you will be ok for highway driving. I'm at 3000 rpms at 85 I think. if the car has 3.55s or something, you may want to swap in an overdrive 5 speed later on.

I would drive it first and see how you like it before you rule the car out
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Old Jan 31, 2013 | 01:09 PM
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I too have a Doug Nash in our 71. Been in it some 30 years. 3:36 rear gear which gives equivalent of 5:13 out of the hole. Has been a good transmission for many years. 5th gear is straight thru.

Do have a question however. Seems to have excessive slack in gear shift lever before resistance is met to indicate that gears are being shifted. Also a bit of a problem finding neutral at times,,,I have used alignment pin to insure all is lined up internal in the shifter ok.

Was wondering if shift rod grommets are the issue. They look fine but I recently ordered up a set from Hurst website. Little messy on their site to find the proper part number. Correct part number is 3327302. If I had not taken the time to call them before ordering, I would have ordered 3321657 which is incorrect. Have not received yet, will post how this works out.

Also seem to have a slight oil leak at front of transmission when full to fill plug. When leaked enough to drop level down a bit, the leak goes away. Anyone have any information on a seal, gasket or perhaps loosened fit tolerances at the mainshaft or other area at front of transmission????
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Old Jan 31, 2013 | 01:55 PM
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Originally Posted by Sxrxrnr
I too have a Doug Nash in our 71. Been in it some 30 years. 3:36 rear gear which gives equivalent of 5:13 out of the hole. Has been a good transmission for many years. 5th gear is straight thru.

Do have a question however. Seems to have excessive slack in gear shift lever before resistance is met to indicate that gears are being shifted. Also a bit of a problem finding neutral at times,,,I have used alignment pin to insure all is lined up internal in the shifter ok.

Was wondering if shift rod grommets are the issue. They look fine but I recently ordered up a set from Hurst website. Little messy on their site to find the proper part number. Correct part number is 3327302. If I had not taken the time to call them before ordering, I would have ordered 3321657 which is incorrect. Have not received yet, will post how this works out.

Also seem to have a slight oil leak at front of transmission when full to fill plug. When leaked enough to drop level down a bit, the leak goes away. Anyone have any information on a seal, gasket or perhaps loosened fit tolerances at the mainshaft or other area at front of transmission????
My tail shaft seal was leaking when I first installed the trans but it was because I forced 2 qts of fluid in the trans and over filled it. The specs say 2 qts, but for some reason mine only holds 1 qt before it ovr flows out of the fill hole. I changed the seal and filled it til it just over flows and no more leak.

If you can;t get the slop out of the shifter, it might be time to replace the whole thing with a Long. the Long shifter is really tight and has nice short throws. also has a reverse lock out.
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