5spd Transmission Whine (Page 1/1)
Sundowner MAY 08, 04:31 PM
2 years ago I swapped out my 5spd Getrag on my formula with one from a donor 88 GT.

Everything works fine. But this transmission makes a very obnoxious whining noise when the drivetrain is under load. If I take my foot off the gas or coast the noise goes away.

It feels like maybe I got a very tired transmission with a worn shaft or bearing, and that sound is just resonating through the shift cables right into the cabin.

I picked up transmission #3 but I probably will hold off on yet another engine drop until the fall. In the meantime it would be nice if I could minimize the noise and enjoy driving it a little this summer.

Any suggestions? (currently it is filled with pennzoil syncromesh and at the proper level)
Patrick MAY 08, 05:34 PM

I'm only familiar with the notorious Getrag rattle... which disappears when the clutch is depressed. Other than that, my Getrag is pretty quiet.
Larryinkc MAY 08, 05:47 PM
I have a 3800 swap with an aluminum flywheel that caused the famous Getrag rattle at idle in neutral. I won't recommend that you use what I use I will give you the benefit of my experience.

I put Redlne 75W140 gear oil my Getrag and it quieted the rattle some I still wasn't happy with the way it sounded. Shifting was the same as as it was with lighter gear oils I had used.

5W140NS GL-5 Gear Oil - Quart

Contains extreme pressure additives like our 75W140 GL-5 oil, but lacks friction modifiers to balance slipperiness
Popular for historic and vintage transmissions, like Mid-1930s to early-1950s synchro-equipped gearboxes in cars and trucks
Helps with noisy or rough shifting in troubled A-833 Dodge/Plymouth 4-speed transmissions from 1964 to 1969
Option for noisy transmissions when mixed with 75W90NS or MT-90 to bring viscosity level up
Also used in clutch-type limited slip differentials in racing for maximum lock up-some users add Limited Slip Friction Modifier in small doses to customize slippage
Non corrosive formula, safe for use with all synchro materials

I now have Redline Heavy Shockproof in my transmission and it is much quieter. I have used it for years in motorcycle transmissions and rear bevel drives so I am familiar with it and what it does. Redline does not recommend it for synchro transmissions but a google search will reveal that many people do use it in transmissions. The shifting is the same as it was with all the other gear oils I have tried. I don't drive my car in the winter but a couple of years ago at a Fall track event there was ice on the roof and windshield and it shifted just fine. I have several thousand miles with the Heavy Shockproof and no problems.


Heavy ShockProof Gear Oil - Quart

Film thickness greater than an SAE 75W250, yet low fluid friction like 75W90
For heavily-loaded racing differentials and transmissions, problem gearboxes
Most popular ShockProof product, many racing and specialty applications
Many performance racing applications like Sprint, Midget, Dirt Late Model and Quick Change Differentials, Detroit Lockers and spools, NHRA Top Fuel and Funny Car rear ends
Not recommended for most synchro applications due to the product's extreme slipperiness

https://www.redlineoil.com/gear-lubricants
fieroguru MAY 08, 06:16 PM
The whine is likely worn differential bearings. The check is to try to rock one of the tripots and see if the other one moves. It is does, the differential bearings are shot. It would be good to check the spare transmission before putting it in.

Raydar MAY 08, 06:47 PM

quote
Originally posted by fieroguru:

The whine is likely worn differential bearings. The check is to try to rock one of the tripots and see if the other one moves. It is does, the differential bearings are shot. It would be good to check the spare transmission before putting it in.



This. Exactly.

Also... does it whine in all gears? Or just one?
I had one that lost its drain plug on the highway, on the way home from work. It got quite loud.
Since I was only a few miles from home, and had no idea what was going on, I just decided to nurse it home, very carefully.
It still whines just a bit in 5th gear, but it's been that way for quite a few years, and quite a few long trips.
pmbrunelle MAY 08, 07:16 PM
Replace/shim bearings in transmission #3, and fix up anything else that needs attention while you're in there (spider gears, cross-pin, etc).

Drop the cradle and replace transmission #2 with #3 when:
The whining sound gets really too loud
When the transmission blows up
If you want to take the car on a long trip, but don't trust it with its actual transmission
When the driving season comes to a close
Sundowner MAY 09, 08:41 AM

quote
The whine is likely worn differential bearings. The check is to try to rock one of the tripots and see if the other one moves. It is does, the differential bearings are shot. It would be good to check the spare transmission before putting it in.



I hadn't considered this... I've never really messed around with the cv axles or anything inside the transmission besides the clutch, so I'll have to read up.


quote
Also... does it whine in all gears? Or just one?



All gears and it gets louder/higher with speed.
82-T/A [At Work] MAY 09, 09:19 AM

quote
Originally posted by Sundowner:

All gears and it gets louder/higher with speed.




It might not be the transmission at all. I know you said it happened after you swapped it in... but any chance it could be the wheel hub? Wheel bearings tend to also whine when they are starting to go out... just a thought.
fierosound MAY 09, 11:55 AM

quote
Originally posted by Sundowner:

I picked up transmission #3 but I probably will hold off on yet another engine drop until the fall.
In the meantime it would be nice if I could minimize the noise and enjoy driving it a little this summer.





Muncie 5-speed service manual in PDF.
https://fieroinfo.com/manuals/

The 88 Factory Service Manual PDF also has a section on diagnosing the 5-speed Getrag.

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Sundowner MAY 09, 12:24 PM

quote
It might not be the transmission at all. I know you said it happened after you swapped it in... but any chance it could be the wheel hub? Wheel bearings tend to also whine when they are starting to go out... just a thought.



I'd say it's at least within the drivetrain and not the wheels because it only whines when the transmission's under load. The noise is much more associated with walking through the gears. I'm no expert either so who knows, but when I've experienced wheel bearings going bad they have always just been a consistent steady noise that just gets louder with overall speed and may get better/worse depending on how the wheels are turned.

I actually do still have transmission #1 sitting in my garage as well.. The sad story there is that I backed out of my driveway one day about a month after getting the motor rebuild done, and it just got "stuck"... if I tried to let out the clutch in any forward gear it would stall out the engine. I pulled it out and took it to a transmission shop in RI where they promptly put it on a shelf and ignored it for months. Finally after several phone calls I got it back half apart and pieces of it in a cardboard box. Then I brilliantly left it in the back of my truck for a day or two and it rained and most of the parts now have a nice brown patina. Maybe now is a good time to try tinkering around with it and learning the parts before I try and crack open a serviceable one.

Thanks guys.