wide ratio FS5W71B slipping out of 3rd & 4th

[Jeff Berk]

I started this question in another thread but instead of taking over that thread, I thought it best to start a separate one.

I have a '74 260z with an engine and drivetrain from a 280z or 280zx. The transmission is a wide ratio FS5W71B. 

The transmission would slip out of 3rd and sometimes 4th gear when I let up on the gas. I replaced the transmission fluid with Red-Line MT-90 and replaced the 3 ball bearings and springs (detent springs 32831N). There does not seem to be anything interfering with the shifter and the transmission seems to go fully into gear.

I test drove the car today and the problem seems to persist. According to the service manual, after eliminating the springs as the problem, the next thing to look at are the Shift Fork and the Gears. 

My question is, whether I could tackle this level of rebuild or is this something best left to a professional? I'm also not sure how available the gears and shift fork are for this old unit.

Note that the ball bearings for the springs came in packs of 10 so I have 7 extra if someone needs any along with an extra spring since I ordered an extra expecting to loose one.

Thanks

Jeff

[siteunseen]

I had a problem with mine popping out of 5th and reverse after going to a 5sp. It was the shift rod hitting and not letting it go fully into gear. I ground some off where the nicks were and it's okay now. 

 

Edited November 12, 2020 by siteunseen

[Zed Head]

Here's your other posts, using the bipod thing.

 

[Zed Head]

Ownallday just did his.  It takes some specialized tools and some knowledge about mechanical stuff.  You might not have to go that far.  The clutch forks are easy to get to once the front case is removed.  But if you find a bearing like Ownallday's it gets more complicated.

 

[siteunseen]

7 minutes ago, Zed Head said:

Here's your other posts, using the bipod thing.

Are my bipod thing copy and paste not showing up right? I'm using my phone and it looks good on my end. Just curious, you've mentioned that a couple of times to my replies.

[Zed Head]

Yours are working.  I meant Jeff Berk's other posts when I pasted his bipod link.  He had tagged on to pogden's thread.

[Jeff Berk]

I don't think its the Shift Lever hitting anything. I checked from under the car while my son shifted back and forth between 3rd and 4th and it looks like nothing was binding or hitting. 

Moving to the shift fork as the next potential cause, it looks like the part potentially causing the problem would be #27 (31805) or #28 (32809N).  Unfortunately, those parts are NLA. If worn out at contact points, can these parts be repaired, redressed, or built up with welding? Or are they available as replacements through other channels? I'm just wondering if rebuilding is even an option.

Edited November 13, 2020 by Jeff Berk

[Zed Head]

The roll pin holding the fork has been known to loosen up or fall out.  The fork from a 4 speed would work.  Somebody will have a used fork on the forum or eBay.  Hard to imagine that you won't be able to find one.  You can figure out a lot without tearing it down very far.  Once you get the front case off you can manipulate the shift rods and forks and gears and see what's happening.  Then you'll know how deep to go.  Plus it might save on having a pro fix it if it's half torn down already.

You can always do what a typical Z owner does and just buy a whole transmission, fix the other one anyway, and feel good knowing that you have a spare.  Then buy another shell to put all your spare parts in.

[Jeff Berk]

After putting in a new clutch, I sold my transmission jack figuring I'd never do that again. Wrong as usual. I did a quick check and found a rebuilt 5 speed close ratio nearby but at >$1,000 I'll see what I can do with my transmission. Anyways, I don't want a spare transmission since I'm limited on space and with winter knocking at our door, I need to get all three cars in my 2-car garage.

At least this will give me a winter project.

I'll jump back on this thread once I get around to pulling the transmission.

Thanks!

Jeff

[Jeff Berk]

I'm getting around to disassembling by 5-speed to search for the cause of the slipping out of 3rd and 4th and I'm already stuck. I removed the stopper guide pin, return spring plunger, return spring plug, and plunger. I need to remove the tail end of the transmission and removed the six bolts that pass through the adapter plate and now I'm stuck. Do I need to remove the dust cover sleeve (No. 11) and seal (No. 10) to pull the tail section off? If so, is the dust cover sleeve screwed on? After their removal, just hammer and twist left to pull the tail end, right?

 

[Zed Head]

Did it come part way off then get stuck or has it not even broken the mating surface yet?  Pretty common to have to do some wiggling and shaking to get it completely off. 

Also, are you sure it's not a close ratio with the reverse lockout mechanism?

[Jeff Berk]

Zed...

The dust shield has a small gap between it and the body of the transmission tail piece. I've tried prying with a screw driver and twisting with a pipe wrench. Before I get too aggressive, I just wanted to make sure I wasn't missing anything. I'll try and wiggle it with a dead blow hammer and prying.

I'm assuming that the dust sleeve and seal need to be removed to pull off the tail end of the transmission.

I'm sure it's a wide ratio based on it having two bolt tabs at its tail end and I don't see what looks like a reverse lockout mechanism.

Jeff

Edited January 3, 2021 by Jeff Berk