'82 SC Transmission Noises/Questions

[deguitars]

For the last four years I've been trying to bond with my '82 SC but the 915 gearbox is really just not very friendly and to be honest diminishes my enjoyment of the car. I'm fairly certain it's not a case of "user error" or inexperience with manual transmissions. I'm 51 years old and have driven every kind of manual transmission you can imagine including 18 wheel rigs which have no synchros at all.

I have no doubt the 'box will need attention at some point (as well as a clutch) but I'm looking for thoughts, opinions, etc. on just what you guys think I'm dealing with as far as what's causing the symptoms. I realize this is a bit like "hold your car up to the phone/computer and let me diagnose it" but the symptoms are fairly clear and not that many in number. There are two main issues: Shift quality and Noise.

First Shift Quality. Shift bushings are new and perfectly adjusted. Swepco in the case. I can drive this car smoothly most of the time but it just shouldn't require so much deliberate babying IMO. Some of the issue I believe is to do with the clutch being on its last legs. The car has 90K miles and has had one clutch replacement at 34k when the original rubber centered disc gave up. Engagement is towards the top of the pedal and fairly vague. While driving it can honestly be harder to get OUT of gear than INTO much of the time, especially if I'm hard on the go pedal. And the TO bearing is noisy. So as long as I don't mind waiting around for glacier-paced shifts I can manage. But it's a sports car, right?

Secondly there are specific, consistent noises. It's a noisy gearbox. None of the synchros seem especially bad, only light crunching in second if I rush it. Slips easily into first at any reasonable speed. First and second gears are mostly quiet but third and fourth are certainly not. Applying power at lower speeds, 2nd and 3rd in particular, sets up a "groan" or "rumble" until speed picks up. Getting on and off the power there is more of a "clatter" at pretty much any speed any gear except maybe 1st or 5th. Interestingly, if I feather the throttle (any gear) there is a "space" where I'm neither on nor off the throttle where it's sorta "floating" that the clatter is silent. To me this sounds like a bearing? I'm curious if the hard to get OUT of gear symptom noted above is related? Too much loading of something due to bearing wear? Or just the worn clutch?

That's about it. I hope I've described this in a way that makes sense. Any input is greatly appreciated.

Cheers

[jjeffries]

You definitely need to replace the clutch then adjust the cable too..cannot judge the gearbox with one so worn. Worn pedal cluster bushes can add to the misery, too.

Some will say Kendall Dino 80/90 is better than Swepco.

Ideally find someone with another 915-equipped car and compare that to yours.

Google the Peter Zimmerman 915 overhaul Wiki and at least read the first chapter; this gives you an idea of what you or a rebuilder will be up against. There are ball/roller bearings throughout the 915 that could be making noise, and a couple whose outer races may have spun in the case.

I too have an 82 SC, and find it a noisy ride, but its the engine fan noise that I hear, mostly.

Best of luck, John in CT.

[Flat6pac]

The double arm on the clutch I think you will find is a great part of the pressure and TOB noise.
When the time goes by the spring arm attaches itself to the vertical shaft engaging the fingers to the TOB.
You need to drop the arms off the vertical shaft. The longer one may take heat to loosen it on the shaft. It is supposed to idle on the shaft, not stick to it. Clean and grease or anti seize after cleaning and reload the cable and adjust.
Bruce

[deguitars]

The double arm on the clutch I think you will find is a great part of the pressure and TOB noise.
When the time goes by the spring arm attaches itself to the vertical shaft engaging the fingers to the TOB.
You need to drop the arms off the vertical shaft. The longer one may take heat to loosen it on the shaft. It is supposed to idle on the shaft, not stick to it. Clean and grease or anti seize after cleaning and reload the cable and adjust.
Bruce

Do you think that could really be the source of so much clatter and whine? I guess it will have to wait until the day when I can drop the motor and take a look.

Thanks for the input guys!

cheers

[Flat6pac]

You don’t need to drop the motor to free the arms BUT you need to free the arms before you drop the motor in order to split the trans off.
Get the spring arm to idle on the vertical and lube it. Drop the circlip, then the short arm. Now if I’m wrong the spring arm will pop forward with a large screwdriver, releasing the clutch cable, and pivot freely, remove the long arm and antiseize it. Put it all back together.
Looks like I’m the only suggestion so far and you’re looking at an hour work to prove me wrong
I see this problem at least a couple times a year on the 915.
Bruce

[Matt Monson]

from the left, 4,3,2,1. Noises in 3&4? I think you’ve got a bad bearing in the case with loose races like so many of these 915s these days.

The long term issue is it let’s the gears walk out of parallel alignment. Including the ring and pinion.

[Reiver]

Before you decry the 915 what shape is it in...how many miles, has it been rebuilt?

I love mine, works as it should and is fun as it does take some skill.....if you want a modern car, many now even match rpm's on downshift, then buy one.

You are talking about a 35 year old box with how many miles?

[deguitars]

Bruce, I am not familiar with the actual procedure you're referring to so I might PM you for more details. I'm fairly handy and it doesn't sound like a big deal so I'm happy to give it a try.

Matt, thanks for your reply. It's actually noisy in pretty much any gear, but 1st and 5th are the most silent of them.


cheers