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5 speed swap?


Gearheadcurt

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The '77 was the first year the 620 had a 5 speed option but it can be retro fitted into trucks back to '74 at least to replace the 4 speed (or automatic). If you have an automatic the easiest thing is to buy another scrap 620 that has a standard in it so you have all the parts needed. Even if it's just a 4 speed you can get it going and hunt down a good 5 speed and easily swap it in later. Or you can begin to hunt down all the parts separately, but this may take more time.

 

You will need the clutch and brake assy, including any springs, clips, switches and bolts. Be sure to get the push rod to the clutch master with the adjusting nut and clevis pin.

 

A clutch master cylinder. They can be bought new to avoid buying a leaky hunk a junk.

 

A clutch slave cylinder. They can be bought new to avoid buying a leaky hunk a junk. Get the push rod to the clutch arm too.

 

A hydraulic hard line and a flex line to connect the master to the slave. I used a pre made brake line with the correct metric threads and length and made the bends myself. The flex lines can still be bought.

 

5 speed transmission. It may come with the slave cylinder still bolted on, and may have the clutch arm and boot as well as the release bearing sleeve, shifter and proper rear mount to frame. If not you will have to find these items too.

 

The round release bearing is pressed onto the sleeve (behind it) and the sleeve clips to the clutch arm sticking through the side.

720dieseltrans002Large.jpg

transreleasebearings5Large.jpg

 

A six bolt flywheel and the six standard mounting bolts. Can't use the automatic bolts.... too short. There are 200mm and 225mm clutch sizes available. Measure across the contact surface for the size.

 

This one is 240mm

flywheel240mmthree2Large.jpg

 

The flywheel determines the release bearing sleeve used so do not blindly use the one that might come on your 5 speed. Likely it's a 225mm but you never know.

 

A pilot bearing to press into the end of the crankshaft for the transmission input shaft to ride in. motorpilotbushing005Large.jpg

 

 

All automatics have a small plate over the end of the crank. This must come off to get the flywheel on.

 

Spacer plate on:

motorZ24crankauto.jpg

 

Spacer plate removed for flywheel:

motorZ24crankstandard.jpg

 

 

 

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Everything on a 4 speed transmission (clutch arm,boot,shifter,slave) will fit the 5 speed.

 

As you have an auto and may not be familiar with the 4 or 5 speed, here's a way to tell them apart.

 

Four speeds look just like the 5 speed, but have a small long rectangular cover plate just forward of the shifter held on by six bolts and with a breather cap. Like this:

 

CopyofF4W71Bfrom75620001LargeLarge.jpg

 

The five speed here are without this:

 

IMG_0308.jpg

 

This leaves one more thing. In the picture above there is only one L series 5 speed that will correctly bolt up to you L20B motor. The other is a Z series for use on Z series motors. The trouble is, it will bolt up to your motor but will be tilted with the shifter leaning over into the passenger seat and with a mis aligned rear mount. If you could have one free would you know which one to take? Well mistakes are sometimes made by honest sellers and easily done if the transmission isn't in a vehicle. So here's how to tell them apart....

 

LansZtrannybell003Large-1.jpg

 

If you stand at the back of the tranny and look forward along the top center line there is a casting seam or rib that runs along the length and up the 'bell housing' to a bolts that attach it to the motor. The picture above happens to be from a Z series motor and so about an inch to the right hand side of the rib is a mounting bolt hole. (the left one is about 4inches over and can't be mistaken)

 

 

LansZtrannybell002Large-2.jpg

 

This is an L series transmission. Very similar to the Z series. Here, the close bolt hole is and inch to the left side of the rib. All you need to remember is L series is Left side

 

This guy is awesome

 

Thank-you, thank-you. I'm here till Thursday. Try the veal. :lol: Now with what you've learned, which transmission is the L series in the picture with two transmissions????

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thanks for clearing all this up,

yes the truck I'm looking at is an auto, and what I think I'll be doing is collecting the parts over time

 

ok, I didnt know that about L series trans,

so there is only one trans that can be used with my motor, did this same trans come out of any different cars? (so I can search for them in junk yards)

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Here is a list of vehicles to check. The 5 speeds are a drop in swap to your '77. They are:

 

'77-'79 620 truck

'77-'78 280z

'79-'83 280zx

'79-'84 810/Maxima (gas or diesel)

 

 

It should be noted that the '79 620 has the widest ratio gear set with the '77-'78 620, 280z and Maxima having a middle ratio set and the 280zx a close ratio gear set including a very high over drive ratio 5th gear.

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I was pointing out that there are 5 speeds that can easily be mistaken for the L series just like a 4 speed is similar to a 5 speed. The Z series were used in cars and trucks in the '80s and they will bolt up to an L series motor but have the wrong tilt. You may come across a 4 or 5 speed already out of the vehicle, so now you have the info to tell a 4 from a 5 speed and not take a Z series home with you.

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Here is a list of vehicles to check. The 5 speeds are a drop in swap to your '77. They are:

 

'77-'79 620 truck

'77-'78 280z

'79-'83 280zx

'79-'84 810/Maxima (gas or diesel)

 

 

It should be noted that the '79 620 has the widest ratio gear set with the '77-'78 620, 280z and Maxima having a middle ratio set and the 280zx a close ratio gear set including a very high over drive ratio 5th gear.

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  • 2 months later...

I just swapped a pre '74 4 speed into my '79, in place of the stock 5 speed. I needed the front section (from the tranni to the carrier bearing) from the pre '74, and the back section from my '79 (But mine is a king-cab, so that makes the back section longer). If they're both standard cab, the only section that should be a different length would be the front section, and which one you use would depend on the transmition. If the tranni is shorter (pre '74), you'll need the front section of the drive-line, if it's longer (post '74) you'll need the one for that tranni.

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  • 12 years later...

Thanks a lot guys.

I am swapping a 4 speed to an L series transmission I bought from eBay to my currently mounted L20 B motor, now I know exactly what I need.  Before I read this article I was totally lost.  Just a couple more of questions:

Does the 5th speed go to the right of 4 and above R?

Where can I get a shift knob?

I would like to have the 5 gear transmission shiny and clean before I mount it.  I even plan to paint it, any suggestions to help me to achieve this?

I need some guidance to see what kind of grease, oil or other fluids have to apply.

Originally, I didn’t plan to swap transmissions, therefore I asked my mechanic to replace the old clutch disc, what he did.  Can you please tell me if I can use the installed 4 gears clutch disc in a 5 speed transmission?  Is there any video or assembly exploded I can follow to do it?

Thank you very much again.

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1...3..5

NNNN

2..4..R

 

Power wash the outside, dry, rattle can silver or light gray.

 

Use GL-4 transmission oil NOT GL-5.

 

Use lithium grease on the clutch arm and pivot ball contact surfaces, clutch arm and slave push rod contact point, lightly on the clutch disc splines.

 

Yes you can use the 4 speed clutch and pressure plate. Be sure to use the 4 speed release bearing holder or collar but put a new bearing on it.

 

I recommend a new ($5) rear transmission seal while the 5 speed is out and easy to get at. Grease the seal lips so it doesn't start up dry.

 

Pry out...

 

YAHhY2W.jpg

 

Tap new one in...

 

NZvrFa1.jpg

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6 hours ago, Alfredecu said:

Do you know where I can get the rear transmission seal?

What about the new bearing for the existing 4 speed release bearing holder or collar?

Thank you very much

Both are easily obtained items, rockauto has them and you could probably get the seal from nissan still not sure if they would still have the bearing... those can be sourced by the part number on the bearing if you want anything better than what rockauto has....

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GL-4 is not always easy to find. Last time I purchased (2021/2022) I bought 10 gallons from Starfire Lubricants, it was $49/5 Gallon bucket. Recently, when servicing a Kubota Tractor, I purchased Chevron 1000 THF, since it met the Kubota UDT Specs. The PDS literature it states that it can be used in non-hypoid GL-4 applications and the Brookfield viscosity is 40,000, which is "thicker" than Redline MT90 (32,000). It is readily available and about $20/gallon, cheaper than Redline. I wouldn't hesitate to use it in Datsun, Toyota, or VW GL-4 transmission applications. 

 

TTF-3 Chevron 1000 THF.pdf

 

Starfire doesn't normally stock GL-4 90wt, but they can blend it. May have some in stock at your local distributors. 

 

Distributors - STARFIRE

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I have typically used Redline MTL mixed with 75W-90 for my Mitsubishi transmissions (they call for 75W-85) but you are right, it's  not cheap.  Way more now than last time I bought it.

 

I'll have to check into Starfire or the Chevron. 

 

Thanks.

Edited by iceman510
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