Zx 5 speed rebuild

[Patcon]

8 hours ago, heyitsrama said:

I wonder if you can TIG it with an appropriate feed rod. Might have to manage the heat as well, don’t let it cool off too fast. 

Shaping them after will be interesting, might be able to file it down slowly.

Hopefully we can see some lights on that Christmas gear tree you have.. maybe during the holiday season 😛 

I hope that tree is empty by Christmas!! Lol

We do have a TIG rig. I could go ask our welding rep

Edited April 18, 2021 by Patcon

[Zup]

@Mark Maras

[Mark Maras]

 I'd go with the welding reps advice.

[Captain Obvious]

Without a complete professional heat treat afterwards, there's no way I would put welding heat to an internal transmission gear like that.

It's just a reverse idler, right? Only engaged when you shift into reverse? I'm no transmission guy, but unless it looks like one of the teeth is going to come off and get wedged between other teeth (and avalanche), I would just run it the way it is.

Make sure your clutch is adjusted properly, come to a complete stop before shifting into reverse, and put the trans into any forward gear first right before you grab reverse. Do those and it won't get any worse.

[Patcon]

27 minutes ago, Captain Obvious said:

Without a complete professional heat treat afterwards, there's no way I would put welding heat to an internal transmission gear like that.

It's just a reverse idler, right? Only engaged when you shift into reverse? I'm no transmission guy, but unless it looks like one of the teeth is going to come off and get wedged between other teeth (and avalanche), I would just run it the way it is.

Make sure your clutch is adjusted properly, come to a complete stop before shifting into reverse, and put the trans into any forward gear first right before you grab reverse. Do those and it won't get any worse.

The concern about heat treat is what exactly?

[Captain Obvious]

You want the gears to be hard enough to be "tough" and "wear resistant" but not so hard that they're "brittle". And you want the heat treat to be predictable through the part.

Welding heat would definitely take the metal above the temperature where the original heat treat would be changed. And without knowing how it changed, it's risky. After welding, it might be harder, softer, or exactly the same. It's all a crap shoot and the only safe thing would be to start over. And even that comes with issues because you don't know what the original spec was.

I just see the whole thing as risky. I mean, not that I've never done risky stuff, but, you know...

[Captain Obvious]

You don't need a welding rep.

You need a metallurgist and an automotive transmission engineer.

[EuroDat]

I wouldn't weld it. It could make the chipping worse.

The chips are not as bad as I thought they were. I assure I have seen worse and they worked fine for thousands of miles without giving any trouble.

The most I would do is clean them up a little with a dremel grinder. Be a little carefull using reverse and definitely don't try pulling it into reverse while the car is still rolling forward.

The most probable cause of those chips is people hitting reversewhen they come outof 5th to go back to 4th. It tends to happen more when the selector bushes are worn.

That is why they added the reverse lockout in the later version of the FS5W71B and C transmissions.

[Patcon]

I am gonna post some links. There was some good info in there too.

The engineers seem to agree, welding the hard surface is not a great option

https://www.eng-tips.com/viewthread.cfm?qid=254331

https://www.eng-tips.com/viewthread.cfm?qid=314909

[Jeff Berk]

On 4/16/2021 at 11:42 PM, EuroDat said:

I corrected that in my FSM and posted it in a thread here somewhere 3 or 4 years ago. The problem I had was the original document has a password.

I could not change it or add any comments.

I use https://smallpdf.com/unlock-pdf

[Patcon]

So here is where we're at

This a panoramic photo which is why it has some distortion

My concern right now is on the front side (left) of the main plate. the first two gears don't line up very well. All the rest of them line up pretty good. Now I haven't torqued anything down yet

I thought we might have had the countershaft gear on backwards but I've double checked my pictures and I think it's right side out. Also the snap ring on the inside of the bell housing plays a part too

[EuroDat]

That seems normal. When the input shaft is fully installed with circlip it does not bottom out like it does now in the photo.

What you can do to check if its not too rxcessive is measure the distance between the front faces of the two gears. Then install the front transmission housing. Push the input shaft in until it bottoms out and measure the difference between that position and the position with circlip installed. The difference should be pretty close to the gear faces measurement.