Second gear crunch

Rodger

Rodger

True Classic
About 7 years ago when I did my carb to FI conversion on my '79, since I had the whole drive train out, I decided to take apart the transmission to get rid of the 2nd to 3rd upshift crunch. I used the "5 speed 101" instructions to disassemble and reassemble and it all seemed to go well. It's been quite a while, so I can't remember exactly what I replaced (I think it was the synchro), but it did get rid of that crunch on the upshift. I used Redline MT-90, as recommended on this forum. It was all fine for a couple of years, although only a couple of thousand miles at most. Of course, I have had a continual slow leak of the Redline that drives me nuts, but I top it off from time to time.

Anyway, for the past couple of years, it has developed a crunch going from 1st to 2nd and from 3rd down to 2nd. Not everytime, but at least 50%. I just haven't had the energy to deal with dropping the transmission again, but I have been driving the car a lot this summer and I am really getting tired of the crunch (plus the endless Redline on the floor).

I am going to put the K20 project on hold for a while and tackle the '79 transmission issue, but am looking for advice on what I should be looking for and what I probably need to replace. Since I will have the drive train out, I am also going to be changing the rear wheel bearings and doing a total brake system refresh.

One last question regarding the shift linkage. The '79s have a unique shift rod and linkage to the transmission that does not use the lollipop. I have the shift rod from the '81 K20 swap car. Is there a significant difference in how the shift linkage feels with the lollipop as opposed to the hard linkage of the '79? Since Fiat when back to the lollipop after the '79 run, I am wondering if it is a better solution. Since I will have the transmission out, it seems like a good time to change the shift linkage while I am at it. Thanks for any advice.
 
I don't think there is much of a difference in feel. The lollipop isn't exactly compliant rubber in my experience. It gets down to parts availability if the all steel solution is no longer available for a '79

As for the rest of your post, I will be traveling down the same path with my '87 as shifting up into 2nd is impossible without a major graunch and down is generally good. Your transmission uses quite a few different parts from mine but the basis is the same in regards to how it works.

In your case I would suspect you will want to replace the entire second gear, the sliders and the various parts of the syncros. You will also likely need the synchro for 3rd gear. Once you have it apart it should be more apparent.

You may find you will need to get new selector forks as well.

IMG_1368.GIF


Image courtesy of:
http://www.spiderroadster.com/xtrans7.htm
 
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I wasn't able to find any correct new 2nd gears. The Yugo replacement needed shaving down and still isn't perfect.
 
Good to know. I do have the tranny from the '81 that is not being used, so I may be able to get parts out of that if needed, but I have no idea what condition it is in. When I bought the '81, the engine would start fine, but there were no brakes so I couldn't drive it to see how the transmission was. I should have put it up on jack stands to run it through the gears, but didn't think of that soon enough.

My problem with my mechanical skills is that I am good at taking things apart and putting them back together, but with limited experience working on cars other than the X, I am not very good at diagnosis. When I redid the transmission the first time, I really wasn't quite sure how to recognize worn parts so there may have been parts that I should have replaced, but just didn't know what to look for.
 
Rodger said:
About 7 years ago when I did my carb to FI conversion on my '79, since I had the whole drive train out, I decided to take apart the transmission to get rid of the 2nd to 3rd upshift crunch. I used the "5 speed 101" instructions to disassemble and reassemble and it all seemed to go well. It's been quite a while, so I can't remember exactly what I replaced (I think it was the synchro), but it did get rid of that crunch on the upshift. I used Redline MT-90, as recommended on this forum. It was all fine for a couple of years, although only a couple of thousand miles at most. Of course, I have had a continual slow leak of the Redline that drives me nuts, but I top it off from time to time.

Anyway, for the past couple of years, it has developed a crunch going from 1st to 2nd and from 3rd down to 2nd. Not everytime, but at least 50%. I just haven't had the energy to deal with dropping the transmission again, but I have been driving the car a lot this summer and I am really getting tired of the crunch (plus the endless Redline on the floor).
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You must have replaced the third gear synchro as you fixed the shifting into third crunch. Now you need a second gear synchro to fix the going into second gear crunch. Usually, second gear is the most abused. You don't necessarily need to replace the gear itself if you haven't been grinding much or for a long time. On the X1/9 gearbox, the 1st and 2nd gear synchors are the same p/n and are cone-style. Under $50 from Midwest. Redline ceratinly isn't a panacea for worn-out parts and its benefits would mostly be seen in applications where the transmission oil is being pushed to its limits. It is not strictly the correct oil for the 'box as it is a GL-4 oil which does have some amount of EP additives in it. You can find many threads stating the old, "all I know is that I've never had a problem with it" but EP additives are surface active, they plate-out under high pressure and they change the coeffiecent of friction between surfaces when they do. There is nothing in the X1/9 gearbox that requiers EP additives and they may infact be detrimental to it's shift quality. It's up to you to decide if you want to trade the risk for the added protection that the Redline synthetic offers. If you want to try an experiment, you could drain all the Redline out and put in the correct GL-1 lubricant (available at NAPA) and see if there is a difference. Certainly, the GL-1 is not a cure-all either, but it is a little bit higher viscosity (SAE90) and will build a thicker oil film. It isn't going to change the condition of the parts but it might ease the situation for both the grinding and the leak.
 
and there are many year changes on swapping parts (from what I have been told). So swapping parts is not as easy as it sounds.
 
Paul Valente said:
You must have replaced the third gear synchro as you fixed the shifting into third crunch. Now you need a second gear synchro to fix the going into second gear crunch. Usually, second gear is the most abused. You don't necessarily need to replace the gear itself if you haven't been grinding much or for a long time. On the X1/9 gearbox, the 1st and 2nd gear synchors are the same p/n and are cone-style. Under $50 from Midwest. Redline ceratinly isn't a panacea for worn-out parts and its benefits would mostly be seen in applications where the transmission oil is being pushed to its limits. It is not strictly the correct oil for the 'box as it is a GL-4 oil which does have some amount of EP additives in it. You can find many threads stating the old, "all I know is that I've never had a problem with it" but EP additives are surface active, they plate-out under high pressure and they change the coeffiecent of friction between surfaces when they do. There is nothing in the X1/9 gearbox that requiers EP additives and they may infact be detrimental to it's shift quality. It's up to you to decide if you want to trade the risk for the added protection that the Redline synthetic offers. If you want to try an experiment, you could drain all the Redline out and put in the correct GL-1 lubricant (available at NAPA) and see if there is a difference. Certainly, the GL-1 is not a cure-all either, but it is a little bit higher viscosity (SAE90) and will build a thicker oil film. It isn't going to change the condition of the parts but it might ease the situation for both the grinding and the leak.
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Awesome info! Thanks so much!
 
Rodger said:
When I redid the transmission the first time, I really wasn't quite sure how to recognize worn parts
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This time when you get it torn down, take clear, detailed photos of each suspect component and post on Xweb. There are guys here that will be able to offer input if something looks bad.

For the most part I do not subscribe to the "just replace every part with new" philosophy. It does not make financial sense (unless you have unlimited funds, in which case you would not be doing your own repairs). Some items will be difficult to tell the precise condition just by visual examination but if everything is working well now (except for the isolated crunch in 2nd) then most likely all you need is the 2nd syncro. That being said, syncros are the most common wear component in a trans (they are sort of 'sacraficial' to prevent gear destruction when meshing) and for the most part syncros are relatively cheap so maybe consider replacing all of them this time. But you will know more once its apart.

And if you can get by without your X for a few days, then I suggest waiting until you see what you really need before ordering any parts...the list will most likely change. Plus you are already experienced at doing a 'X' trans overhaul so it will be easy this time. :)
 
I agree with Dr. Jeff, but add your own time into the mix. You've already got it apart. Do you want to spend another 8+ hours after you've "fixed it" pulling it apart and replacing something you didn't do the first time and need new gaskets again anyway? Do you value your time at $.05/hr or $10/hr or more? Just have that in the back of your mind.
I hope none of us has this as their primary transportation--count on it being apart for several days while you formulate your plan.
 
Rodger said:
Awesome info! Thanks so much!
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Second gear can wear in four areas: the actual gear teeth themselves, the side points, the ribbed cone that mates with the syncro ring, and the gear's center bore. Of those four, the ribbed cone is the least obvious, because to evaluate the cone, you need a brand new syncro to fit onto the cone. When placed on the cone area of the gear, the syncro ring has to have a certain amount of clearance between its base and the body of the gear. In 5-speed 101, Steve Hoelscher says that a new syncro ring should yield 0.050 clearance or better, but if the clearance is 0.030 or smaller, the ribbed cone on the gear is too worn and the gear needs to be replaced.
 
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Agreed replacing parts willy nilly is not a good practice. And generally I don't buy parts ahead of time (that are not general maintenance) either. Except for house projects which always follow the formula of buying what I planned, returning to buy what I need and finally a return to the store to return what I didnt need.

Given Rogers statements it's likely that the syncros on both sides of second need replacement to deal with the issues stated there. It is possible it will need a new second gear but inspection will be the key to that possibility.

Personally I would replace the synchro ring for third if I had the unit apart as the third gear synchro is the next most likely failure point but again inspection will tell the story.

On mine the above is how I expect I will have to proceed.
 
kmead said:
Except for house projects which always follow the formula of buying what I planned, returning to buy what I need and finally a return to the store to return what I didnt need.
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Let me correct that: "buying what I planned plus things I saw and thought I would need, returning to buy what I need, returning to exchange what I bought for ones that aren't damaged, returning to exchange the replacement items for the correct replacement items, return to the store to return what I didn't need, return to the store with the right receipts to return what I didn't need. Then go to another store hoping to find what I originally went to the first store for."

I think he replaced the third gear syncro already?
 
Dang I have had that particular sequence as well with the addition of: we don't sell that it came from a different store...

Yes he did but given it's a @45 dollar part and it is already pulled apart so why not...

"Since it's apart" some of the most expensive words in the English language
 
I had a chat with Matt at MWB yesterday, and he basically confirmed what others have said. Most likely the 1st and 2nd synchros need replacing, but that the second gear may also need to be replaced depending on the wear of the cone. Matt said that this very common and usually the first to go in this transmission. I did replace the 3rd gear synchro when I had it apart originally and the transmission only has about 6,000 miles on it since then, but I will take a look at everything and post some pictures of the typical wear points. I did order a few parts that I would need anyway for other things, but will hold off on any of the internal bits until I get it apart. This forum is amazing! If someone had told me a few years ago that I could take apart and rebuild a transmission, I would have said they are crazy. And now, I get to do it AGAIN!! The fun just never stops. :)

And yes, I am right along with Kevin and Jeff on the returns experiences. :(
 
Since I am taking the transmission apart, one thing I have thought about doing is swapping out the final drive for a taller one. I picked up the final drive gear and pinion from a Strada (I think) many years ago on ebay and have just had it sitting in a box. I love driving the X, but at 60-70 miles an hour on the freeway, the engine turning at about 4,000 RPM gets tiring. Guess it is a sign of getting old. :oops: Since I did my FI conversion and did the performance head from MWB, the car has a lot more zip to it. I just don't want to lose all of the acceleration I gained from the performance mods, but it would be nice to reduce the RPMs a bit. Anyone have any input or experience with doing that?
 
Who's this Kevin guy? :cool:

Thanks for writing about your discussion with Matt, it is one that I will be having in the near future as well and expect similar news
 
At the risk of ruffling a few feathers, I'll go out on a limb (lots of bird references) and say...

[Warning, purists cover your eyes, this has content rated "U" for unconventional]
Even if second gear has some wear or minor damage, you could very possibly do just as well to replace the syncros and reuse the gear as it is. Especially considering the difficulty (and expense) in finding a replacement 2nd gear*. Normally I am the type to replace such items when I find a little wear/damage, but think about it for a second. It is currently performing well as it is (aside from the worn syncro) and we have all seen extremely worn/damaged parts come out of a tranny that was still being driven daily...and would continue to do so if not for the persuasion of a repair tech to have it rebuilt. Granted this may present some added risk of future failure, which could cause even greater damage should it go. But frankly a complete, good used replacement trans can be had at reasonable cost if that ever happened. Consider the expense:risk ratio. Also consider your own personal comfort level, not for everyone.

*As 'Henway' found,
Henway said:
I wasn't able to find any correct new 2nd gears. The Yugo replacement needed shaving down and still isn't perfect.
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And no offense Henway, but I understand the modified Yugo gear is not working so well, still crunches when shifting to second? But I highly admire your attempt at a solution to the supply problem.

Legal disclaimer, I am not advocating that you put worn/damaged parts back in your trans. But hell, I just might do so myself. In fact I did once. It was a car that I had no interest in restoring but was otherwise in decent usable shape, aside from severe trans damage. I tore the trans down and reassembled it with a mix/match of used components from assorted other units (some of those parts were extremely bad). I was surprised how well it worked, without any 'new' parts going in. Drove it for years after with no failures. By comparison I've also spent WAY more money on replacement parts to fix a unit that could have been completely replaced with a good used one for a lot less. I'm reminded of a quote from a close friend that owns a very successful independent BMW repair shop: "know when 'good enough' is good enough". Might be different if it was for a valuable, collectible, rare vehicle that is worth pouring limitless funds into, or maybe my daily driver that I rely on to get my family everywhere. But these are certainly neither (at least I hope they aren't for anyone). ;)

Maybe I'm just flapping my wings here (couldn't resist another bird reference).
 
Got it out of the car and apart. It may be a couple of days before I have time to take apart the gear clusters and take some close up photos.
IMG_2754[1].JPG
 
Hey Rodger,

while you have it apart, I'd suggest replacing the slider as well as the synchro. I had a similar issue with 3rd - 4th and only replaced the synchro only to find out that it made no difference. A second tear down and slider replacement finally fixed the issue.

Dom.
 
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