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280zx trans into 620 question


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Collar length was different due to different pressure plate thicknesses. Use the collar that matches your flywheel/pressure plate, not the one that matches the transmission.

 

 

As for the '82 280ZX 5-speed ina '76, well, that's what I'm running right now. '82 280ZX NA (Non turbo) 5-speed in a '76 KC. Just had to swap the mount of the bottom and the speedo drive cog, both of which came straight off the original 4-speed. I used the 280ZX shifter though.

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Forgot about the year, yes the zx shifter will have to be used. The zx shifter looks like the bottom one and I think has slightly shorter throw than the top one.

 

http://i138.photobucket.com/albums/q251/datzenmike/Tranny/720shifter010Large.jpg[/img]"]720shifter010Large.jpg

 

Be sure to change the $5 rear seal, it's good insurance against leaks later and having to remove the driveshaft.

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As for the '82 280ZX 5-speed ina '76, well, that's what I'm running right now. '82 280ZX NA (Non turbo) 5-speed in a '76 KC. Just had to swap the mount of the bottom and the speedo drive cog, both of which came straight off the original 4-speed. I used the 280ZX shifter though.

 

How'd you like the difference in drivability between each trans? Would be good to hear the pros and cons before I do it myself.

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Well, I have an L18 and a Weber in the truck, not original but it's what was in it when I found it.

 

Taking off from a dead stop is more boggy, since 1st gear isn't nearly as low as the truck gearbox. Acceleration is hurt a lot in 1st, a little in 2nd, but 3rd-4th are no different than the original 4-speed (4th is identical, being 1:1 in both 4-speeds and 5-speeds). 5th is a huge overdrive compared to a truck overdrive, 0.745:1, better than 25% RPM reduction vs 4th gear. It is great for freeway cruising. At 60MPH the RPMs are well under 3000.

 

 

Cons: Acceleration from stop, especially up hills or with a load is extremely poor.

Climbing severe grades in 5th isn't gonna happen. Moderate grades are OK as long as you keep the speed up, otherwise you'll have to drop to 4th to get back up to speed. That's not abnormal with tiny engines and overdrives though. City fuel mileage unchanged or slightly worse due to not having a tall enough 1st.

 

Pros: Helluva lot quieter at freeway speeds. 25% reduction in top gear engine RPM. Great gas mileage on the freeway- I get close to 35MPH highway, though it's not all due to the transmission.

 

As a side note, I've replaced the stock 4-speeds in several of my trucks with truck 5-speeds. That retains the same 1-4 gear ratios and adds an overdrive, just not as severe as the ZX overdrive. More in the 0.864:1 range, which was used on 77-78 trucks and 77-79 Z/ZX cars. It basically splits the difference in top gear- if you were turning 3500 RPMs in 4th, the Trucks and '77-79 Z/ZX tranny would turn a bit over 3000RPM and the '81-83 ZX trans would turn just over 2600RPM.

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4.375, which is what all '76 US-spec trucks had (and 75, and 77, and 78).

 

But I'm also thinking that the 411 would have smaller tires (I'm running 205/75R14s in back), so the shorter final drive wouldn't be as bad. Most Datsun cars after '68 had ratios in the high 3.80s.

 

As far as fitting a 5-speed in the 411, the dogleg would be an OK choice for clearance purposes. The 71-series transmissions are so much larger. Kinda depends on what's in there now (knowing that your 411 isn't stock in the drivetrain department anyway).

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4.375, which is what all '76 US-spec trucks had (and 75, and 77, and 78).

 

But I'm also thinking that the 411 would have smaller tires (I'm running 205/75R14s in back), so the shorter final drive wouldn't be as bad. Most Datsun cars after '68 had ratios in the high 3.80s.

 

As far as fitting a 5-speed in the 411, the dogleg would be an OK choice for clearance purposes. The 71-series transmissions are so much larger. Kinda depends on what's in there now (knowing that your 411 isn't stock in the drivetrain department anyway).

 

Since it's a '78/'79 L20b, I'm guessing the 4-speed is similar vintage. Need to crawl under and check.

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