FS5W71B transmission identification (close-ratio vs. wide ratio) - with pictures

[Jeff Berk]

3rd gear is the issue. 

Are parts generally still available? Zcar Depot sells a rebuilding kit that includes seals, bearings, and synchros. But if it's something else, is it possible to still get parts?

[Zed Head]

EuroDat put a paper together and has posted a lot about rebuilding.  The parts are generally available.  I think that you can get them cheaper than at ZCD if you search around.  Seems like there are one or two sets of parts that everybody resells.  There might be extra parts in a kit or a couple of missing parts, but the bearings and seals in the kits seem to be of good quality.  The synchros can be questionable.  Have you found any metal on the drain plug magnet?

 

[EuroDat]

2 hours ago, Jeff Berk said:

I'm trying to ID my transmission because I need to check if parts are still available. All I know is that it came out of a 280z or zx since it was installed in my 260 around '83. Based on the retaining bolt placement above the speedo cable and the two tabs on the tail end of the transmission housing it is likely a wide ratio FS5W71B. Is this the only potential transmission or do I need to dig deeper. There is an L3 on the housing if that helps.

Also, from talking to a transmission specialist, my problem of popping out of gear may be related to worn shoes or forks. If he is on the right track, are these components still available? I'm going to pull my center console out to see if something is blocking the shifter before bringing it in just in case it's a simple issue.

Thanks in advance...

Jeff

Hi Jeff,

It looks very much like a wide ratio FS5W71B out of a 280Z or a 280ZX 2+2. The L3 is a casting mark from the manufacturer and doesn't mean anything regarding type of transmission, ie wide or close ratio.

Popping out of third is caused by an accumilation of wear in several bearings in the transmission, but also springs in the selectors. This typically happens in third because the wear in the needle bearing between the input and main shaft, and third is the furtherest away from the adapter plate bearing. The selector springs loose tension over time and the extra stress caused by the worn bearings pushes it out of gear.

The spring is in the selector parts list in the link @Zed Head posted. 32831N is the part number. They can be replaced with the transmission in the car.

The springs cost a couple of dollars and with a good oil you should be able to drive trouble free for some time. GM or AC Delco make a very good oil for these transmissions. I would try this before doing an expansive rebuild.

 

 

 

[pogden]

My wide ratio gearbox (the one in the pictures at the top of this thread) pops out of 2nd gear. Not always when upshifting, but always when downshifting. I've been reading everything I can on this site about overhauling one of these things, and I am going to give it a shot. I just received the rebuild kit from Rock Auto, which seems to be the exact same one sold by other places as described in @zKars's lengthy  FS5W71B Rebuild Thread, and it was <$60. I also ordered a bunch of other small parts (seals, main shaft and countershaft nuts, detent springs/balls, oil gutter, Torx screws) that I might need from Courtesy Nissan. I did not order any of the big parts (gear sets, shafts) - I understand that many of those are NLA. 

Regrading slipping out of gear, I have no idea why it's doing that, but I hope to find out. My *guess* is either a problem with the 1-2 baulk ring or maybe one of the detent springs. Thanksgiving project, I hope. 

 

 

[EuroDat]

30 minutes ago, pogden said:

My wide ratio gearbox (the one in the pictures at the top of this thread) pops out of 2nd gear. Not always when upshifting, but always when downshifting. I've been reading everything I can on this site about overhauling one of these things, and I am going to give it a shot. I just received the rebuild kit from Rock Auto, which seems to be the exact same one sold by other places as described in @zKars's lengthy  FS5W71B Rebuild Thread, and it was <$60. I also ordered a bunch of other small parts (seals, main shaft and countershaft nuts, detent springs/balls, oil gutter, Torx screws) that I might need from Courtesy Nissan. I did not order any of the big parts (gear sets, shafts) - I understand that many of those are NLA. 

Regrading slipping out of gear, I have no idea why it's doing that, but I hope to find out. My *guess* is either a problem with the 1-2 baulk ring or maybe one of the detent springs. Thanksgiving project, I hope. 

 

 

Might experience. Worn bearings and weak detent springs 32831N. Change the bearings or springs or both and you should solve the problem.

If it goes into 2nd gear without grinding, then there is nothing wrong with the balk ring or the springs 32602N in the hub. If those springs weaking they do not apply enough pressure to the baulk ring and release the hub too soon, before the gears can synchronise and then you grind gears.

[pogden]

5 minutes ago, EuroDat said:

Might experience. Worn bearings and weak detent springs 32831N. Change the bearings or springs or both and you should solve the problem.

If it goes into 2nd gear without grinding, then there is nothing wrong with the balk ring or the springs 32602N in the hub. If those springs weaking they do not apply enough pressure to the baulk ring and release the hub too soon, before the gears can synchronise and then you grind gears.

Thanks, Chas. I just might be able to fix this then - I also ordered the large roller bearings (the ones not included in the rebuild kit, for some reason). What you say about the baulk rings makes sense, but I'll probably replace them anyway (cuz I have 'em). But I'll give the old ones a good inspection first. 

 

[Jeff Berk]

EuroDat and Zed Head... Thanks for the help. I downloaded the service manual for the FS5W71C from NICOclub and it shows the first thing to check for wear are the plug return spring and ball. The diagram provided by Zed Head shows 3 of them. 

EuroDat, how do you access them without removing the transmission? Are the plugs visible on the outside of the transmission? If so, can you point them out on one of the photographs in the first post of this thread?

I'm going to pull the drain plug this weekend and check for metal shavings. There weren't any 3 years ago when I pulled and reinstalled the transmission, but that was 3 years ago.

Jeff

[Yarb]

Jeff, I believe these two pics show the location @EuroDat is referring to. Pics 2&4.

[EuroDat]

Here is a photo where you can just see the two side detents in the red circle ( 3rd/4th and 5th/reverse) the other one (1st/2nd) goes in from the top and is the hardest to replace. It helps to lower the rear transmission mount and crossmember to give yourself more room.  You will also need a small pencil style magnet to remove the spring and ball.

 

 

Edited November 6, 2020 by EuroDat

[Jeff Berk]

Thank you... I think I found them using your annotated photos. Switching out these inexpensive items are worth a shot before having the transmission rebuilt. 

Do I need to spray anything in the holes after removing the springs and check balls to clean out gunk or should they be fine.

Euro Dat, That is one clean transmission!

Jeff

[EuroDat]

54 minutes ago, Jeff Berk said:

Thank you... I think I found them using your annotated photos. Switching out these inexpensive items are worth a shot before having the transmission rebuilt. 

Do I need to spray anything in the holes after removing the springs and check balls to clean out gunk or should they be fine.

Euro Dat, That is one clean transmission!

Jeff

Thankyou. You shouldn't need to clean out the holes. Not much debris gets in there unless a ball has completly fallen apart.

When you remove the springs, compare the free length with the new one. You should also notice theold springs compress easier when you depress them.

Your problem is an accumulation of things. Removing the (weak springs) issue will give you some time. Maybe 10 to 20 thousand miles before it really needs rebuilding.

Don't forget to change the oil for a good quality gear oil like Red-Line MT-90 75W90 GL-4 Gear oil. There is also the GM and AC delco friction modified syncromesh transmission fluid. AC DELCO USA part number is: 88900399. GM USA part number is: 12377916.

Last thing. When you drop the cross member don't drop it too far and check the top radiator hose and fan that they don't get damaged.

[Jeff Berk]

FYI, the drain plug didn't look too bad so hopefully the new springs will take care of things. I'm picking up the Red-Line tomorrow.

Thanks all.