Roaring in lower 3 gears, what to check?

[ScoopMan]

Getting a lot of noise in lower gears sometimes, especially 3rd, but the obnoxiousness varies, sometimes it is tolerable, sometimes it is really reall loud. 4th gear is nice and quiet tho. I am guessing it must be some failing bearing in the trans. Otherwise it shifts fine. Just wondering what to check. Rebuilt trans are $1950, ouch, hopefully I do not have to resort to this. I have not yet checked the oil level in the trans, wondering also how best to do this.

I am very new to the Fiat Spider world, I only picked up the car 2 days ago. Thanks in advance...

[Mathew26]

Well it certainly could be the bearings, but you never really know. Is the sound coming from the trans or is it just a general loud noise? Also if there is a problem with the trans and it needs a rebuilt one we at VAS offer them for $1250 not $1950 (that is really high). Did the last owner tell you when he/she last changed the trans fluid? If not I'd recommend changing it out.

[ScoopMan]

Thanks, good suggestion Mathew. I am going to shoot an email to the previous owner and find out about the oil.

Because it is pretty mellow in 4th I am thinking it is probably the trans and not a driveshaft bearing or something else, but I have not yet had the time to jack up the car and look around under there just yet. As I said it is not super loud ALL the time, but sometimes it is pretty deafening. If it is indeed the trans and it is not too ridiculous a job, I might yank it out before it gets too cold, and either replace whatever bearings and seals myself or get another trans. $1250 is sure a lot less than $1950, I will certainly keep yall in mind.

[Mathew26]

Good luck and I hope you find its just a simple fix.

[majicwrench]

If it is noisy in other gears but not 4th it is almost certainly a trans bearing. No point changing the fluid now, the damage is done. Needs to come apart.

[ScoopMan]

Bummer. If so then how much is worth routinely replacing, and how much can be re-used? Should all bearings be replaced? What about synchros? It is shifting OK... BTW I have never opened up a trans before... Then again a first time for everything right?

What about deferred maintenance? Will it be likely to blow into bits of useless scrap if I keep running it, or just be obnoxiously noisy?

[BEEK]

layshaft bearing bad, maybe only 1, if the noise goes away in 4th, 4th gear is direct and doesnt use the layshaft. these transmissions are fairly easy to overhaul, if you have a mechanical aptatude. bearings are available from many suppliers. myself i would build my transmission way before i bought a rebuilt one. as to how long it will last, who knows. depends on the severity of the damage. the one thing for sure is it wont get better. you could / should drop the pan on the trans and inspect, if no chunks of metal, bearings are laying in the pan, then its possable to drive it for some time, refill with proper lubricant and go with it. ive driven 124's with noisy transmissions for many years, the syncro's and shift hubs will wear out first usualy.

[ventura ace]

If it is noisy in other gears but not 4th it is almost certainly a trans bearing. No point changing the fluid now, the damage is done. Needs to come apart.

I share Majicwrench's opnion that the cuprit is likely one or more bearings making noise. Since the noise goes away (yes??) in 4th gear, the one bearing that's making the most noise may be the pilot bearing between the input shaft and output shaft, since both of these shafts rotate at the same speed in 4th gear, but not in any other gear.

Does the noise goes away when the car is not moving, with the cluthch pushed in? If yes, that suggest that your clutch, crankshaft pilot bearing, and throwout bearing are OK.

With the car not moving, tranny in neutral, clutch out: the input shaft (1 bearing), counter shaft (3 bearings) and input/output shaft pilot bearing are spinning. Any noise then?

Since the oil only costs a few bucks (1.5 quarts total), I would certainly change it out to see if the noise is substantially reduced, and if so, I'd keep driving it until it showed other problems. As magicwrench said, some damage is likely already done, but maybe it's not bad enough that you can't get several thousand more miles out of it, provided you don't mind listening to a little rumble from scored bearings. First check the oil level to confirm your suspition that it may be low. That is the lower plug on the passenger side of the tranny, which is the fill plug. You should always remove that plug before draining the transmission, to make sure that you can get the plug out and can refill the tranny. Look for debris in the oil that you drain out, and measure the volume to see how much was actually in there. If you see broken parts and big chunks of metal, then you'll need to take the tranny apart, or else those broken bits can get thrown around and damage other parts of the innards.

Add fresh 90 wt GL-1 or other suitable non-EP replacement oil. I use 50 wt Valvoline racing engine oil (same viscosity as 90 wt gear oil), and get great service and performance. After filling the tranny, crank the engine and run it for a while in neutral, with the clutch out. If there had been a lot of noise, and now it gets better, then take the car for a drive. If noise has diminished to something fairly benign, then you're probably good to go for several more years, and you've saved about $1000 or more for now. If it's still obnoxiously noisey, then you may have to pull the tranny out for surgery. Before doing that, you could drop the pan and study all the innards from below, just to see if anything jumps out at you that could possibly be fixed with the tranny in place (not likely, but worth a look).

Good luck with it.

Alvon

[ventura ace]

. . . if the noise goes away in 4th, 4th gear is direct and doesnt use the layshaft. . . . .

well, not exactly. All the shafts are spinning (input shaft, output shaft, layshaft) in all 5 gears, and even in neutral the input and layshafts are spinning. What's different in 4th gear is that the input shaft and ouput shaft are locked together and spin at the same rpm, so the pilot bearing between those 2 shafts does not get exercised in 4th gear. True, it doesn't 'use' the layshaft, but the layshaft is still spinning, and all 3 bearings on it are spinning.

Alvon

[ScoopMan]

Thanks Beek and Ventura Ace. For now I will probably drop the pan and take a look, then refill with new oil and see how it works.

The noise is only REALLY bad when the car is moving, 3rd gear especially, but not terrible all the time. Little noise from the TO bearing really.

If I go ahead and end up yanking out the trans and opening it up, is it a good idea to replace other bits like syncros anyway, even if it is shifting OK? I would probably put in a new clutch, PP, TO bearing as a matter of course if I did.

[majicwrench]

I still see little advantage in spending the time and money changing the fluid, or pulling the pan, but that is just the world I live in. Trans needs to come out, and come apart. No need to change a lot of parts if it is shifting well, just replace bearing(s). You really do not HAVE to change all the bearings, but I probably would. You may be able to get thousands of miles out of it the way it is, running the metal fillings thru all the gears, synchros and bearings till the whole thing is scrap metal. Better to pull and repair sooner than later.
Keith

[BEEK]

. . . if the noise goes away in 4th, 4th gear is direct and doesnt use the layshaft. . . . .

well, not exactly. All the shafts are spinning (input shaft, output shaft, layshaft) in all 5 gears, and even in neutral the input and layshafts are spinning. What's different in 4th gear is that the input shaft and ouput shaft are locked together and spin at the same rpm, so the pilot bearing between those 2 shafts does not get exercised in 4th gear. True, it doesn't 'use' the layshaft, but the layshaft is still spinning, and all 3 bearings on it are spinning.

Alvon

there is no power transfered thru the layshaft, as there is in all other gears

[ScoopMan]

I still see little advantage in spending the time and money changing the fluid, or pulling the pan, but that is just the world I live in. Trans needs to come out, and come apart. No need to change a lot of parts if it is shifting well, just replace bearing(s). You really do not HAVE to change all the bearings, but I probably would. You may be able to get thousands of miles out of it the way it is, running the metal fillings thru all the gears, synchros and bearings till the whole thing is scrap metal. Better to pull and repair sooner than later.
Keith

I am sure you are correct Keith, thanks. Problem for me right now is time, just way too busy with work right now to take the time to yank the trans and take it apart, but I can probably find enough time just to swap some new oil in now so that I can keep driving the car until it gets cold. Hopefully I will find the time to do the right thing before next spring.

Besides the trans, the car also needs front end work, an engine gasket or two where it is leaking, and some electrical gremlins dealt with, so I need to pick my first battles.

[ventura ace]

To Keith's point, if you find metal filings, broken bearing retainers, or any other weird stuff like that in the oil, you should strongly consider changing more than just the oil. Otherwise, the metal pieces that are still tumbling around in there are destructing other parts. However, if the only metal you see is some gold colored stuff from worn synchros, you may have lucked out, and could consider running the tranny longer (assuming the noises pretty much go away).

Alvon

[ScoopMan]

Well Alvon it gets pretty loud so I don't think I will get lucky. However I think I might be willing to waste an hour or so of my time now and a few quarts of oil just so I can drive the car for another 6 weeks or so until the weather gets nasty and she goes into hibernation. Then I have until Spring to do things properly.

I want to get some leaf peeping in with my girlfriend first