Synchros stuck in Geo Metro 5- speed manual trans

[buggywhip]

I have a 1991 Geo Metro that was in storage for 7 years. The 5-speed manual trans was fine before that, but now I can't downshift to 1st or 2nd without stopping or double-clutching.

Is there an additive or lubricant that can free up the stuck synchros, without damaging the trans? I was told by a mechanic they could be freed up by removing pan and moving them around by hand, but am hoping to avoid this.

 

[XS650]

I don't have an answer for you, but those who might be able to help would have a head start if you told us what the normal recommended trans lube is.

 

[Quest]

Sorry, never heard of that problem before (I owned/serviced Suzukis 1L 3cyl up until 1996).

Try shifting into gear that is in-question, with your engine off, rock the car back and forth and then try disengage it and see if that helps.

Unless you have your gear oil drained and moisture seeped in, otherwise, I cannot see corrosion to the bearings and etc. being the culprit in this case. Maybe something to do with your clutch cable or your pressure plate/flywheel part.

Q.

 

[buggywhip]

Originally Posted By: XS650
I don't have an answer for you, but those who might be able to help would have a head start if you told us what the normal recommended trans lube is.

I just bought the car. The car had the GM-recommended 75w90 gear oil during storage.
According to prev owner, it was replaced with synthetic "15w90", when the synchro problem was found.
I haven't heard of that weight gear oil. I am awaiting a call back regarding what brand it was.
After this gets resolved I am planning to change to GM Synchromesh oil, unless I hear of something better.
Thanks

 

[mechtech2]

If you get it in gear, the synchros are not stuck.
Bad oil or bad design result in balky shifting.

 

[Quest]

91 Geo is essentially a Suzuki gearbox and those MT gearboxes are only good with 75W90, service interval shall typically be around 40,000kms OCI, and strictly 75W90 GL-4 (can acutally use GL-5). Anything else such as 80W80 will cause hard or notchy shifting. Owing to the fact that many of these small vehicle owners tend to abuse/neglect their vehicles during their ownership (my estimate calls for over 70% of abuse), it is not uncommon to have synchros worn out, gear clash (M/T box) or detent not holding in-gear, etc.

First and formost: get some 75W90 GL-4/GL-5 and change it out to see if that helps. If that doesn't seem to help by much and you are having notchy/clashing 1-2-3 gears, I'm afraid that you'll have to go find another used gearbox to swap out (easy 1-man job!), or spend 1000bux + to get it rebuild (make sure that the input shaft bearing is replaced, and check/shim the bearings that hold the differential gears to make sure that they are good).

Q.

 

[buggywhip]

So far, I'm getting the impression that "stuck synchros" are unusual, perhaps an anomaly. I admit I know very little about lubricants, which is why I came here.

I envisioned the car sitting for 7 years and the the oil forming varnish or sludge and binding things up. Is that possible? If so, is it realistic to suppose that a solvent or additive could break this up, and if so, what would it be?

Tomorrow I will try the suggestion of "Try shifting into gear that is in-question, with your engine off, rock the car back and forth and then try disengage it and see if that helps."
Also I will change to 75w90 GL-5. I do have some Royal Purple synthetic. Is that preferable to organic?

I do have a used trans but know nothing of its history. Is there a way to check its functions before I go to the trouble of installing it?

 

[MolaKule]

I would take the pan off if it has a pan and find out what is sitting in the pan. Collect the oil and check to see what kind of particles are in it.

Once the pan is off, have someone shift it and see that the fork slides the gear assemblies/synchros to their proper positions, assuming the synchros still exist.

 

[Craig in Canada]

You could always throw some Auto-RX in there. I'd just use fresh dino 75W90 if you did that.

 

[buggywhip]

Auto-RX, what is that and who makes it?

 

[Craig in Canada]

At first I was flabbergasted that you're a BITOG member and didn't know what Auto-RX was...then I saw you're pretty new

http://www.auto-rx.com/

Lots of respect from all of BITOG, lots of discussion about it in oil additives.

It's most often used in engine oil, but works in power steering, transmissions (manual and automatic) and other applications.

It isn't a high-powered solvent, but it's a fantastic cleaner which does things others cannot and I figure it's worth a mention.

 

[JohnBrowning]

I agree inspection plate action. You could have a bad roll pin a bent shift fork, damaged syncros etc....... If that is beyound you though what you could try is spraying a half can of PB plaster into the trans along with cheap gear lube drive for 500 miles and see what you see. If it helps then drain and refill with Redline MT-90. I have never heard of transmission problems with those normaly it was engine problems I ran into with people when I worked for GM. Since the engines where so underpowered the transmissions seemed to last forever with very little serviceing. I am thinking you have bad or missing syncro wich if that is the case needs to be fixed before it damages the bearings and gear's tot he point that the transmission is not salvageable.

 

[buggywhip]

I received the following advice on another site and wanted to see what you guys think:

"I'd try running some automatic transmission fluid in it. It works wonders on old motors with sticky lifters. It frees up lifters and cleans out oil build up. ATF has a lot of detergents in it. It should be safe to run it in a your manual trans too. A lot of cars now days use ATF in their manual trannies. If it were mine, I'd probaby start by draining about 1 quart of gear lube out and refilling it with a quart of ATF. Drive it around for a couple hundred miles and see if it helps."

 

[buggywhip]

If I use Auto-RX, how much should I add?

PS- Thanks for the welcome! Great site - glad to be here!

 

[INDYMAC]

Lots of good ideas so far. Go to Auto-Rx.com and order a couple of bottles of that. You'll want to ARX the whole car!
Without getting tunnel vision though, have you completely flushed and bled the clutch fluid yet? Difficult to get into gear sounds more like clutch fluid to me, especially the way you describe your problem. Make sure you bleed all the air bubbles out.

The directions for ARX are on the website. It's 1 oz per quart of fluid in the MT, I believe.

 

[buggywhip]

Thanks for the great responses, you guys are great!
Checked the Auto-Rx site. As you said,:
"To get the most out of Auto-Rx®, we recommend the following methods of use: Manual Transmission:
The application ratio is 1 ounce of Auto-RX® per quart of oil. Drive 1,000 miles and drain the Auto-RX® and oil. Refill according to your vehicle manufacturer's recommendation. The application will last for the life of your manual transmission."
Lots of great testimonies there! I'm gettin' some!

Also want to know what you all think of AMSOIL Long Life Synthetic 75W-90 Gear Lubricant, due to this testimony I saw by another Metro owner:
"the very last thing i tried was amsoil's synthetic manual transmission and transaxle gear lube. it was a miracle but not right away. as soon as i changed it i could now downshift from 4 to 3rd at about 55-60 km/hr. a month later by mistake i found not even one little grind or crunch at about 70 km/hr."

 

[buggywhip]

After reading the Auto-RX site i can see it's more compatible with dino oils, so I'll use that for now instead of synthetic.
I'm going to try it also in the engine. The oil gets dirty really fast and it uses a quart every 400 miles.
I'll let you folks know how it worked out.

Thanks so much for all the help!

 

[Craig in Canada]

buggywhip:

I'd get your syncho issue under control before getting $100 worth of ARX and launching into a comprehensive vehicle program. Nothing says that you're going to be able to fix this without opening it up $$$ so get the important stuff done first.

If your synchro issue clears up, then go nuts

As someone else suggested, you should make sure that your clutch isn't somehow malfunctioning as well.

Good luck

 

[buggywhip]

Right. I did try rocking car back & forth in 1st & 2nd but no change. The clutch is adjusted properly and seems to function as it should. I have yet to bleed the clutch or try to look inside the tranny.

Like I said I do have a used trans I know nothing about and I am still seeking advice on how to tell if it's OK before I risk installing it. I've R&R'd a few of these Metro engines and changed axles (it's no biggy), but haven't tackled a transaxle yet.

I did order 2 bottles of ARX for $42US and it should only take 3 oz. or so to treat the trans, so I don't have much to lose by trying it. A couple of testimonials at the ARX site about manual trans results give some hope, assuming they are for real.

If none of the above works I may have to put up with double-clutching a while longer. I don't want to pay $1,000 for a rebuild. I could rebuild it myself - it would be my first, so it might take a few days. Or maybe find another used one known to be good.

It's my third Metro. I switched to it recently because of gas prices. The Taurus was getting avg 22 mpg and so far the Metro is getting 37 city and 48 hwy, all with the AC on.

Thanks for your response!

 

[Craig in Canada]

On the clutch issue, if its worn it can be hanging up and transmitting enough engine power to make shifting difficult or impossible but not enough to stall or keep the vehicle moving while the pedal is pressed.

One of the classic tests is often used if you have trouble engaging first gear when stopped:

- engine idling, gear in neutral, press clutch
- attempt to engage first
- hold with mild pressure against the synchros at the point where it's resisting engaging first.
- reach over with your opposite hand and shut down the engine
- if the shifter drops right into first like butter, you have clutch problems

I'm not sure that this is the kind of thing that you're seeing, but this is what those suggesting clutch problems are speaking about.