gearbox/transmission noise

[8cam]

With my screaming water pump fixed, now I can hear all the other stuff going on. FYI my car sat for 15 years which is never good for rotating surfaces, so I'm prepared for whatever might be happening. I hope.

I have two distinct noises going on. The first one sounds like a bearing noise. Symptoms are a rotating/rattling sound with the clutch engaged (pedal out), trans in neutral. When I disengage the clutch the noise goes away, which tells me it's on the transmission side. Hoping this isn't something too ugly.

The second noise is gear whine, and it's pretty damn loud. Happens in at least the first three gears, noisiest in 1st and 2nd. It might happen in 4th too, but it's a lot quieter then and I'm going fast enough that road noise takes over. This noise goes on when idling along with no throttle, under acceleration and off throttle, up and down with the speed of the car. Definitely gear whine. I'm going to bet the oil hasn't been changed in a LONG time, so it's on the list. I see some posts about Castrol TWS. I also know the Ferrari guys swear by Red Line shockproof oils, which have similar characteristics to motor oils with some interesting additives. Only limitations are they can't be used in pump/filter situations. What's the latest recommendation?

[Kevin]

sounds like it could be normal black tag whine. the early trannies are known as "rock crushers" due to the way the gears are cut. Most replace the factory fluid with bmw fluid

[mike100]

perfectly normal as you described it. pedal in quiets down on the ZF. If the throw-out bearing was bad, it would make more noise, not less, so the noise in in the trans. The amount of whine various from one gearbox to another, but I have seen some perfectly fine units make a lot of noise.

[cvette98pacecar]

Didnt you just pick up this car?

[cvette98pacecar]

Your noises might be normal.
If you have a fidanza lightweight flywheel they sound like a spun bearing when the clutch is engaged in neutral. As for the rear end if you have a 4.09 they scream like a scalded pig.

[xlr8nflorida]

Your noises might be normal.
If you have a fidanza lightweight flywheel they sound like a spun bearing when the clutch is engaged in neutral. As for the rear end if you have a 4.09 they scream like a scalded pig.


A 409 rear should not be loud if they are the Viper gears and installed properly.

[8cam]

Didnt you just pick up this car?

Yep, had it just over two weeks. I haven't heard gear noise like this since my grandfather's old Biscayne with 3 on the tree. Boy that car met an ignominious end.

I can just about guarantee this car is 100% stock, flywheel, trans and rear end, given the ownership history. But sitting for as long as it did is never good for moving parts and I suspect is a big reason it's so loud. If this kind of noise is really normal, I'll be very surprised. Driving in the parking deck felt like it was echoing off the walls.

I'm thinking a fluid change is seriously overdue and might fix a lot of the issue. Any opinions on the Red Line oils? I may give the guru a call and see what he thinks.

[xlr8nflorida]

Mobil 1 synthetic 75/90 gear oil for the rear axle. I'd use 2 small bottles of GM Additive.

I'd use BMW Castrol in the Transmission.

BMW oil 3 Liters TWS 10w60 synthetic oil - Change it every 10-12K miles if you love your ZF-6.

Redline has good products but I'd use the BMW in the Transmission for various reasons which I don't have time to type out right now.

[Kevin]

A 409 rear should not be loud if they are the Viper gears and installed properly.

thought the viper gears were 4.10s

[Franke]

4 cam - Mark, If this car is stock then one of the first things you should consider is the injectors. If original they don't like ethanol fuels and eventually start shorting the coils. I had 4 bad ones and they were a great part of my tranny noise due to some misfire. When I replaced them I was surprised at how much quieter my trans noise was. I have 56K miles on it now. I use redline MTL in the trans and it seemed to shift a little smoother but that could be due to new fluid more than anything else. I would change all the fluids since you could have water vapor contamination due to the years of sitting. Then if the loud gear whine doesn't subside I would pull the box for a look see inside.

[8cam]

All injectors, fuel lines, filter, etc. are brand new. Oil and filter are new, and I just finished replacing all coolant hoses, water pump and tensioner. Trans is up next, and I'll probably do the rear end while I'm in there. From the sound of it, my bet right now is the old (likely original) trans oil is the main culprit. I'll get that done this week and we'll see how it goes.

I'll also clean up the sticky throttle body butterflies - confirmed that's mostly the source of a (really) high idle. When I do get it to idle around 800 it wants to surge a bit. So once this noise is abated and goo is gone from the TB, vacuum troubleshooting begins. I have to admit it's fun having a project to work on again...been a while.

[WVZR-1]

I'll also clean up the sticky throttle body butterflies - confirmed that's mostly the source of a (really) high idle. When I do get it to idle around 800 it wants to surge a bit. So once this noise is abated and goo is gone from the TB, vacuum troubleshooting begins. I have to admit it's fun having a project to work on again...been a while.

Spend some time (considerable time) "REASEARCHING" the cleaning of the "throttle body butterflies" - not just a passing glance at maybe a couple threads but thoroughly research! Actually Marc's comments might be all that's needed:

http://www.zr1specialist.com/HAT%20Web/services/throttle%20body.htm

[8cam]

Thanks, appreciate the link. I believe my problem is with the primary because a light tap brings the idle down, sometimes a couple taps to get it all the way down. The plan is cleaning the primary and very light grease on the edges of the plate. I will also look at the secondaries and clean any issues there, without disturbing the factory coating.

[We Gone]

Mark,

I would still check the Prom to be sure it was updated to the latest GM prom. Just takes a 10mm to remove 2 nuts from the ECM turn over and remove the cover to check. A lot of unmolested 90's have been found to have the original proms.

http://zr1specialist.com/HAT%20Web/presentations/Calibrations.pdf

http://zr1netregistry.com/Portals/0/Images/ServiceBulletins/476503-1.jpg

http://www.zr1.net/forum/showthread.php?t=5935&highlight=prom+change

[8cam]

Yep it's the latest prom, confirmed by Marc. With that set, I'm left with gummy primary and vacuum. Once I get the TB working smoothly, I'll be able to look into vacuum although I don't think it's too bad. The idle surge is very minor, less than a hundred rpm. I did get a little instrument flicker once while idling that low, have to check out the alternator too.

And I have to say, after spending years with Porsches and Ferraris, I LOVE the parts prices on Corvettes! Even the LT5 water pump is cheap compared to a 928 pump, and you would not believe what a 928 radiator costs! I won't even mention a Ferrari alternator....