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I was at the track 2 weeks ago and after my third session I came in, and someone said my car sounded funny. I took my helmet off and drove around the paddock and yup... it sounded funny. I narrowed it down to the tranny.
It makes a whirring noise while in gear with the clutch engaged. I think it goes away (mostly) when I disengage the clutch but leave it in gear. Out of gear, I don't hear anything out of the ordinary.
So today I decided to go on a fishing expedition. I drained the tranny completely. There was some black fuzziness on the magnets (as usual), but the front one was worse by far and felt quite gritty.
After it was fully drained, I tried using my endoscope to see if there anything floating around. But I couldn't really see anything. So I then stuck my telescoping magnet in there to see if I could grab anything. I got a few small chunks. It's hard to tell, but I believe these are from a synchro. Any thoughts?
So now, I'm wondering if I get a replacement tranny and swap it in - then take my time to disassemble and fix this one, or if I just fill it with new lube and run it as is - noise and all and just let it go. Anyone BTDT? Anyone have a good used 5-speed tranny for sale?
I'd find a replacement and rebuild the one you have.
Theres probably many more broken parts lying in the bottom of the tranny just waiting to get caught up when your on a flying lap and cause a big lock up/ shunt.
What year is your manual transmission ? Do you have limited slip?
Those look like bits from one of the syncros. They look like they have a brass coating. Remember reading that the syncro's have brass coating, and the synchro's move froward and backward via the selector forks, which could also be the source.
Those could also be bit from the selector forks
You can remove the tranny and open the top cover and inspect all the syncros as well as selector forks. You can also make a determination if your trans needs to be rebuilt by measuring the gaps between the gears and the syncros. This is discussed in the repair manual.
As for finding a used transmission, what year are you looking for. I recently did a search for a 87+ model and found a few. I know of 2 up in Ontario Canada those were in the 1500 - 1800 USD. I know of two cases with parts from early Pre 82 models here in Oregon. I am not sure where you are located but if you need shipping, the freight shipper will require the trans to be drained and strapped to a pallet, or put in a wooden box. Also they will prefer access to a fork lifts. If you need on these gearboxes PM me directly.
If you need help with disassembly there are some good youtube videos
Great posts guys. I'm leaning toward repair/replacement as well. Will start disassembly. . I also think it's most likely a synchro, but can't tell if there is other damage until I inspect fully.
I'll be looking for an 85+ 5-speed tranny as a replacement so I can minimize down time. This one has an LSD which I could in theory transfer, but I'd prefer to not have to.
If you have any good leads on a 85 - 90 tranny, let me know.
it could be reverse lock out or the detent spring levers.. does it go into gear fine... all of them. proper spring preload for 1st reverse and 4-5th?
if it whines with it in gear, and you are stopped and clutch is pushed in... there is nothing happening in the gear box. the driveline is stopped dead.... thats a clutch or TOB issue.
if it goes away when its ingear and clutch is released, then thats good news and means there is no problem in gear with the driveline rotation. however, the opposite is true if "clutch engaged" means, clutch released and driveline locked to the engine. this is probably what you are saying, correct? that means that something is not right in gear and you are getting a whinning sound in gear and rolling . a damaged synchro could do this, but do you have any synchro problems? starting it up and going throguh the gears from neutral could show if there is an issue there.
sounds also like its coming out anyway. bummer to hear you have to pull it.
That doesn't look like synchro pieces to me. The release bearing always spins on these cars so make sure the issues isn't that before deciding to pull the transmission.
That doesn't look like synchro pieces to me. The release bearing always spins on these cars so make sure the issues isn't that before deciding to pull the transmission.
i agree.. too many straight surfaces. i think its that lever reverse lock out thing-a-ma-jig. its the thing that can fall into the transmission if it comes loose and falls into the transmission. he should be able to tell if all spring functions are working properly.
I would think pretty strongly about doing a C5/C6 trans swap. Up front cost will be more, but should be stronger and a lot more replacement parts are easily sourced.
I have a new plan... I'm going to fill it up with new lube and try to record the noise with the GoPro. See if I can isolate exactly where the noise is and when I hear it. I'm not hopeful, though. I have a few leads on acceptable replacement trannys, and will in all likelihood, pull the trigger by the end of the week to minimize down-time.
Slightly off-topic: I almost pulled the trigger on the Spec: ArialAtom on BaT. Looks so fun!
I would think pretty strongly about doing a C5/C6 trans swap. Up front cost will be more, but should be stronger and a lot more replacement parts are easily sourced.
our trannies are amazingly strong . ive raced, and was very abusive with the holbert transmission. it finally broke after 140 race days and over 8 years of racing . my more recent transmission i have over 50 race hours and all have been on the higher HP stroker motor as well. 400 to 420rw torque.
from a durability perspective, the s4 transmission is a great gear box.
from a cost perspective, at 2500 used, its not a bad deal either.
has anyone totaled up what a complete C6 transmission conversion would cost?
I have a new plan... I'm going to fill it up with new lube and try to record the noise with the GoPro. See if I can isolate exactly where the noise is and when I hear it. I'm not hopeful, though. I have a few leads on acceptable replacement trannys, and will in all likelihood, pull the trigger by the end of the week to minimize down-time.
Slightly off-topic: I almost pulled the trigger on the Spec: ArialAtom on BaT. Looks so fun!
can you describe the problem again in relation the clutch pedal depressed or not or in neutral. (rolliign or not)
do you hear the noise, in gear, but clutch pushed to the floor, coasting??
do all the detents and lever springs seem to be working?
That doesn't look like synchro pieces to me. The release bearing always spins on these cars so make sure the issues isn't that before deciding to pull the transmission.
Originally Posted by mark kibort
i agree.. too many straight surfaces. i think its that lever reverse lock out thing-a-ma-jig. its the thing that can fall into the transmission if it comes loose and falls into the transmission. he should be able to tell if all spring functions are working properly.
Originally Posted by mark kibort
can you describe the problem again in relation the clutch pedal depressed or not or in neutral. (rolliign or not)
do you hear the noise, in gear, but clutch pushed to the floor, coasting??
do all the detents and lever springs seem to be working?
Again, to recap:
Noise is present with car in any gear, clutch pedal out. If I press the pedal in, noise goes away. If the car is not in gear, rolling or not, noise goes away.
Car shifts fine - as far as I can tell. All springs appear to be in place and functional.
The noise is best described as a whirring noise - but started out more like a ticking. It sounds similar to when you put a manual tranny into reverse and you're backing up, but not quite as loud - only it's in the forward gears.
One thing I noticed after I drained the gearbox. I had it on the lift and decided to run it through the gears to see if I could hear the noise with it in the air (gearbox empty). The noise was imperceptible. I was hoping (or not) that I could isolate a particular gear - but all sounded fine. But that may be because there was little to no load on the drivetrain. Obviously I didn't want to run it much at all with the gearbox empty. That's why my plan now is to re-fill the gearbox and run it around the neighborhood to see if I can isolate the noise and determine better the conditions for the noise to be present.
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Noise is present with car in any gear, clutch pedal out. If I press the pedal in, noise goes away. If the car is not in gear, rolling or not, noise goes away.
Car shifts fine - as far as I can tell. All springs appear to be in place and functional.
The noise is best described as a whirring noise - but started out more like a ticking. It sounds similar to when you put a manual tranny into reverse and you're backing up, but not quite as loud - only it's in the forward gears.
One thing I noticed after I drained the gearbox. I had it on the lift and decided to run it through the gears to see if I could hear the noise with it in the air (gearbox empty). The noise was imperceptible. I was hoping (or not) that I could isolate a particular gear - but all sounded fine. But that may be because there was little to no load on the drivetrain. Obviously I didn't want to run it much at all with the gearbox empty. That's why my plan now is to re-fill the gearbox and run it around the neighborhood to see if I can isolate the noise and determine better the conditions for the noise to be present.
yeah, you dont want to run without fluid.. but one way to very easily load up the rear tires and simimulate acceleation load is to use the brake while acceleating. i would fill it and do this.. that way, you dont have road noise to contend with.
also, you say, its in all gears, but if the clutch is pushed in, there is no noise. meaning, its a loaded condition issue. however, can you leave it in gear and not push the clutch pedal in and be at an equalibrim force? (not accelerating and not decelerating) you know , the point were you can pull it out of gear and go to neutral.
those parts, if its the detent mechnaisms, if they ran through the gears, got chewed up, they all might be flushed out of the gears and at the bottom. that might be it. however, if there is a gear that has damaged teeth. sometimes they can wear in and not be a problem.
putting fluid back in and doing a thorough test is a good idea.
from what you are saying, it sounds like a torque tube could be the problem because you say, the noise is in any gear and push the clutch pedal down and it goes away. however, can you push the pedal in and also rev the engine to those same in gear RPM and see if you can hear the noise. if so, that would indicate torque tube.. but you also said in neutral there is no noise.. but did you check reving the engine to a 3-4000rpm level and hold, in neutral?
do the jack stand test , in gear, but ride the brakes to limit RPM. you dont need WOT, but moderate throttle in 3rd gear can be used with brakes to limit RPM to whatever you want and then listen to the load. the force on the driveline is the same as driving, but no road noise and you can have someone listen or you can video tape at the transmission and wheel area.
07-09-2016, 12:51 PM
Coke Car Tranny Issues - Need sage advice
. I also think it's most likely a synchro, but can't tell if there is other damage until I inspect fully. 
