Z 5 SPEED TRANSMISSION SWAP (620 datsun)

[Droski]

Hello Datsun peers 

Looks like I have located a 5 speed for my 1975 620 LB, the tranny is from a Z not sure exact year. Its 31 inches long but I want to confirm it will bolt up before purchase. Thanks for any info in advance. Hope the link below works

 https://ibb.co/LdNrfJd

Edited August 7, 2019 by Droski

[Droski]

https://ibb.co/LdNrfJd

[datzenmike]

 

This is an L series FS5W71B 5 speed made before 1980. The reverse light switch and lack of other switches suggests a car that has EFI and no need for emission switches like the truck did.

 

If you have an L20B it will bolt up to it. I assume you have a 4 speed, so use YOUR release bearing collar but replace the bearing on it. You can use your clutch arm or the one on the 5 speed but you must use your bearing collar.

 

That's an interesting right angle speedometer pinion sleeve. Remove (and save) by unbolting and wiggle slightly but pull straight out so you don't crush the plastic gear. Put your 4 speed pinion in. I've no idea what number of teeth are on this one but your 4 speed is matched to your rear end gear ratio and tire size. The 4 speed pinion will keep your speedometer accuracy the same.

[Droski]

Yes I have a 4 speed, second one in the truck and it's making a strange whirlwind noise (for lack of better words) just like the first trans at high rps and especially in 4th gear on the highway around 50-60 mph. Something just ain't right lol I'm Having to run thru the first 3 gears quickly to avoid hearing this sound. I'm want to make this truck my daily so I'm thinking the 5th gear will be beneficial for highway cruising and also hoping this transmission will hold up better than my last two 4 speeds. Thanks Mike for all your help. Owe ya a beer 😄

[datzenmike]

Well keep the 4 speed. It's common for the $15 counter bearing to go on them and relatively easy to replace it. If you're like me it's always good to have a back up.

[Droski]

Definitely keeping this 4 speed because it still seems to work really well beside the noise. Where can I get a replacement counter bearing ebay?

[Crashtd420]

3 minutes ago, Droski said:

Definitely keeping this 4 speed because it still seems to work really well beside the noise. Where can I get a replacement counter bearing ebay?

There are plenty of bearing supply shops , plus Ebay..... best to remove the old one then just search the numbers on the bearing..... 

[Droski]

Mike one more question, will my original transmission mounts work?

[Droski]

45 minutes ago, Crashtd420 said:

There are plenty of bearing supply shops , plus Ebay..... best to remove the old one then just search the numbers on the bearing..... 

Thank you!

[Crashtd420]

I used this place... good prices quick shipping....

https://3bgsupply.com/

 

Also these guys have alot of the other internal parts if needed....

https://www.midwesttrans.com/FS5W71_Manual_Transmission.html

[Crashtd420]

4 hours ago, Droski said:

Mike one more question, will my original transmission mounts work?

It should..... 

[datzenmike]

7 hours ago, Droski said:

Mike one more question, will my original transmission mounts work?

 

Yes the early 4 and 5 speed 71Bs were almost identical. Use your truck mount and slave cylinder. While it's out it's prudent to do the following...

 

Replace the $4 pilot bushing in the end of the crankshaft. It's easier if you remove the clutch and pressure plate. This is probably the original bushing and very sensible to replace now, same as the release bearing. If they start to squeal 3 months down the road you'll have to take the transmission out again for this $4 part. Don't lubricate, it's sintered bronze and permanently lubricated and supports the front nose of the transmission. I slit down the length with a small screwdriver in 3 places, bend in and fish out the pieces. It's soft so use a block of wood to carefully drive the new one in.

 

 

 

Don't worry about the crank being scratched. It'll just hold the new bushing better.

 

Clean and lightly lubricate the front input splines with a lithium based grease and wipe off excess. 

 

Clean out the old grease inside the release bearing collar and fill the cavity inside it with grease. The housing is the part that clips to the clutch arm and slides along the input shaft

 

Use a new release bearing. Mentioned before. Expect to pay $15-$20 so don't cheap out on this as the transmission has to come out to replace later if it fails from old age and use.

 

Clean the pivot ball the clutch arm sits in and lube with grease as well as the small socket in the end of the clutch arm the push rod rides in.

 

Replace the rear transmission seal in the tail that the drive shaft slides into. It's about $5 but again hard to get at in the car so do now. Pry the old one out tap the new one in using a hunk of 2x4 and a hammer. Use a suitable sized socket to fully seat the seal into the tail. Grease the lips of the seal so it does not start up dry.

 

 

[docbainey]

21 hours ago, Droski said:

Definitely keeping this 4 speed because it still seems to work really well beside the noise. Where can I get a replacement counter bearing ebay?

The 4sp countershaft bearings are needle bearings. I believe the earlier years used caged needles, then a change was made to loose needles. Loose needles will carry more load Vs caged needles of the same dia. (more needles in contact with the rotating parts) I don't know if you can use loose needles in a case that was using caged needles though?

[datzenmike]

The countershaft bearing I'm referring to is at the very front below the main shaft and seats into the front case under the cover plate.

 

 

This is a 71C but only difference is 62mm while almost all 71B are 56mm.

[docbainey]

I thought the 620 came with a F4W63?

[datzenmike]

Only the '73, very much like the 521's 4 speed for ratios or the 510 wagon. By '74 the engine size went up to L18 and with the L20B on the way for '75 it was time for a stronger 4 speed so one was borrowed from the Z car. Well it is a truck and expected to work.