Trans Ratio's by year, model

[RoadRace]

i was going through my links of tech things and found this one was still active after a few years so i thought i'd put it up for the collective.

 

http://www.zhome.com/ZCMnL/tech/GearRatios.html

[datzenmike]

This part is misleading.

 

Special Note#1There was a 5 speed 720 truck('79-'85)transmission that will bolt into an L-6 car, that also has "lower" gearing. However, there were two other sets of different gear ratios available, depending on the truck model:

 

#1 ........... #2 ....... #3

 

1 3.592 .... 3.321.... 3.592

 

2 2.246.... 2.077..... 2.057

 

3 1.415.... 1.308..... 1.361

 

4 1.000.... 1.000 .... 1.000

 

5 0.813.... 0.833 .... 0.813

 

The #1 option used in the '79 620 and the '80 2wd 720 gas motor is the only one that will 'bolt into an L6 car'. Anything after '80 would require the front case to be removed and an L case swapped on.The #1 ratios were used only on the SD22 diesel and the #3 option on the SD25 diesel powered trucks after that. The #1 and #3 were used on the Z22 and Z24 4X4 720s but they would not have had a speedo drive hole machined into the tail stock.

 

The #2 option was used on all models of reg cab short, reg cab long and king cab with Z22 gas motor from '81- Oct. '82. After Nov. '82 the #2 option was only used on the '84-'86 Mileage Option equipped Z20 motor and the Dual rear wheel Cab Chassis model. Again the front case would need changing to an L series case.

[datsunaholic]

Not quite as nicely laid out, but I put this list together many years ago. It doesn't cover the MPG-version 720s though. It's mostly truck-specific. It doesn't cover the early "A" type 71-series trans used in the 240Z either, being somewhat rare.

 

Gear Ratio Table

[LenRobertson]

Here are a couple more pages I have Bookmarked:

 

http://www.datsuns.com/Tech/datsun_transmissions.htm

 

http://newprotest.org/projects/510/gearRatios.pl

 

Thanks to datzenmike for clarifying the truck trans differences. I've always been confused on that subject. If anyone wants to stretch this thread out to several pages, consider the question of which ratio set is "best" for an L-series engine. I know the answer will vary somewhat depending on displacement and horsepower, but in general, is there a clear preference, or obvious ratio set to avoid? I've read many times, the 280 box with the tall 1st gear doesn't work well trying to get a 4 cylinder moving off the line, but that may be a Datsun urban legend for all I know.

 

Len

[datsunaholic]

I drove a 620 with a '82 ZX trans (with that infamous first gear) for 5 years. AND it had an L18. It was a slug off the line, but I got used to it. The 35MPG that huge overdrive allowed more than made up for the VW-Beetle acceleration.