questions after reading other post.

[ronnny]

Ok I have 2 720 pickups. 82 kc z22 5 speed and a 84 regular cab z24 5 speed

 

Someone said they wanted 3.70 gears from a 720. What is usually in a 620? Is this what gears are in my 720s or did many other ratios come out?

 

Someone said the 2.4 don't like to rev high and i felt that in my 82 with the 2.2 like to run better but not sure if it is just that it has a weber on it. both look the same if you did not know any better.

 

Is there a truck i should look for where i can get lower gears for my truck. I do very little highway driving and feel it is geared a little high but the last owner had a little oversized tires on it.

 

What must you do to fit newer nissan wheels on the older trucks or will they fit right on my 720. I would like to use my steel ones for just a spare.

[Nissan_Boy85]

720 Z24...I rev mine to about 4500 getting on the freeway and get decent response. I think they like to rev fine for being a 80's 4-cyl. As for the wheels, there is an adapter you need for newer Nissan wheels, like Titans. Not sure on that, I'm gonna let someone who has done that give you a positive answer.

 

Mind if i add a question that kinda falls in leu with your questions?

 

Is their a rear end narrower by an inch or so that I can throw my gearing into and keep my 6-lug so I can tuck my tires into my rear fenders? Is their anyway I can shorten the spindle so I can tuck teh fronts in too?

[datzenmike]

Ok I have 2 720 pickups. 82 kc z22 5 speed and a 84 regular cab z24 5 speed

 

Someone said they wanted 3.70 gears from a 720. What is usually in a 620? Is this what gears are in my 720s or did many other ratios come out?

 

The '79 620 with standard had a 4.11 differential. The '74 automatic had a 4.625. The '73 manual and automatic had 4.88. For the most part all other years had the 4.375 diff. For the 720 the ratio depends on year, engine and if a 4wd or not. Keep reading to find out what rear end was put in either of your trucks....

 

Someone said the 2.4 don't like to rev high and i felt that in my 82 with the 2.2 like to run better but not sure if it is just that it has a weber on it. both look the same if you did not know any better.

 

Let's just say that without mods they run out of steam at 5,000 to 5,500 RPMs. In fairness they were designed for low emissions, low speed power and torque and have lots of it. The engine size is easy to determine. Usually the Z22 motors have a cast valve cover, the Z24s have a stamped steel one but could've been swapped, so to be sure, it's stamped on the top of the block just below the #2 spark plug.

 

Is there a truck i should look for where i can get lower gears for my truck. I do very little highway driving and feel it is geared a little high but the last owner had a little oversized tires on it.

 

You don't say if your trucks are 2wd or 4wd or if you mean the Z22 or the Z24 needs lower gears.

 

Look on the inner passenger side fender just below the hood hinge. There is a credit card sized aluminum tag with the differential ratio stamped on it. It looks like this:

 

http://i138.photobucket.com/albums/q251/datzenmike/720stuff034Large.jpg[/img]"]

 

Near the bottom is TRANS/AXLE...... FS5W71B............HF38

 

The 38 means 3.889, a 41 would be 4.11 and 43 is 4.375 and so on. Look yours up first, so you know what you have to begin with.

Edited November 9, 2008 by datzenmike

[datzenmike]

Mind if i add a question that kinda falls in leu with your questions?

 

Is their a rear end narrower by an inch or so that I can throw my gearing into and keep my 6-lug so I can tuck my tires into my rear fenders? Is their anyway I can shorten the spindle so I can tuck teh fronts in too?

 

I understand the mid '82s increased in axle length to allow for auto brake adjusters. You have an '85 so 143cm or 56.3" between where the rims touch the axle on each side. Perhaps the earlier '80-'82 were a bit narrower.

[]2eDeYe]

4.11's...that reminds me...

 

Ted I still have your diff :D

[Jester]

Thanks for the info Mike. I was at the yard today and couldn't find a tag on the diff or in the door. Nice to know where it's at. Going to pick up a pair of BMW Z3 seats for the KC for $40.00 tomorrow.:D I'll do a double look at the diffs.

[Nissan_Boy85]

Thank ya much Mike. Sounds like I need to go out to the JY and place a couple side by side and do some intermixing before I buy.

[Jester]

Well, I did my swap today. Bought a 3:88 gearset from a '84. Installed in about 2 hour. Much better for a 4 speed. It also looked better inside than my OEM stuff. Tooth wear pattern was better too.

[datzenmike]

Yeah, if mostly just for transportation you can go that low. If you stop facing up a hill with a big load you'll notice a big difference on take off.

 

Damn, I should have told you, you'll need to change your speedo cog. You now will actually be going faster than your gauge says so you need less teeth on the cog so it spins faster and the speedometer higher.

 

These are for 280Z cars and may not translate over to truck size tires, but if you pull your cog and it's a Purple then go two sizes down to a White. If you have a Red go down two to a Blue.

 

Yellow....... 16 Tooth 3.364.1

Black........ 17 Tooth 3.545.1

Blue......... 18 Tooth 3.70:1

White....... 19 Tooth 3.90:1

Red.......... 20 Tooth 4.11:1

Purple....... 21 Tooth 4.38:1

 

I guess the thing to do is go back where you got the rear end and grab the one from that tranny, but the 720 may have larger tires and an after '80s cog may not fit the '75.

Edited November 8, 2008 by datzenmike

[Jester]

My tires are a little smaller than stock. It was about 6 mph off. I checked it with my GPS tonight and it seem pretty close. I'll check it on the freeway on my way to work on Monday and let you know.

Thank for the info on the differant speedo cogs. Very cool.

[rat tail dragger]

i like to no what gears i have 76 620 with 79 rearend hopefully you havnt already showed it sorry if this question is a repeat

[Jester]

The '79 620 with standard had a 4.11 differential. The '74 automatic had a 4.625. The '73 manual and automatic had 4.88. For the most part all other years had the 4.375 diff. For the 720 the ratio depends on year, engine and if a 4wd or not. Keep reading to find out what rear end was put in either of your trucks....

 

 

 

 

Look on the inner passenger side fender just below the hood hinge. There is a credit card sized aluminum tag with the differential ratio stamped on it. It looks like this:

 

http://i138.photobucket.com/albums/q251/datzenmike/720stuff034Large.jpg[/img]"]

 

Near the bottom is TRANS/AXLE...... FS5W71B............HF38

 

The 38 means 3.889, a 41 would be 4.11 and 43 is 4.375 and so on. Look yours up first, so you know what you have to begin with.

 

 

This thread was AWESOME for me. I had no idea either where to find the gear ratio in my trucks.

 

 

THANKS AGAIN MIKE!!

Edited November 9, 2008 by datzenmike

[datzenmike]

The 620s don't have any way of telling that I know of other than the year or lifting one wheel and counting the drive shaft turns and divide by two. I also add the '73 diff to the list it's a 4.88 and an aluminum case I believe.

[Jester]

You know, I actually thought about that last night after I posted. DOOOO! We don't have tags on our 620's. :lol::lol: Although one has a sticker.

[ronnny]

Looked today and the newer truck 84 has a 3.7 and the older one has a 3.8 Not much of a difference but sure is in driving these two trucks. The 2.2 5 speed does better on both take off and top end than the 2.4 5 speed does on either. The 2.2 is also a kc so i figured it would be slower from the extra wieght. The 2.2 also seemed to get about 2-4 more mpg than the newer 2.4 no matter how you drove it. Oh well i will fiure this out in time. Thanks for the information yall.

[BarryA]

The 620s don't have any way of telling that I know of other than the year or lifting one wheel and counting the drive shaft turns and divide by two. I also add the '73 diff to the list it's a 4.88 and an aluminum case I believe.

 

that lists the rear axle ratio - in this case, the hood is original to the truck and the engine compartment has never been painted - probably why the tag is still there and legible.

[datzenmike]

I don't know if the older ones had it listed on the emissions sticker or not, good to know about the '79 though. Usually the sticker is illegible, peels off or the hoods been changed.