LT-1 Larry

I just finished installing a Richmond 5-speed and a 3.08 rear end in my 71 LT-1. Absolutely love the performance, but it has a VERY annoying rattle/growl in all gears from about 20 MPH up. I know that it is a heavy duty tranny, and a certain amount of gear whine will be there, but this is definitely more than I would expect, and I think it's a problem with balance or a bad bearing or something. Here's a little background: I bought the unit used, but took a look inside and it looks like new. The gears and synchros were perfect. I didn't pull it apart at all, and did not inspect the bearings. After installation, this rattling/vibrating began coming up through the shifter (Hurst). It would occur in any gear, and even with the engine off and coasting. I figured it might be a loose slip yoke, so I installed a new one. When the car was up on the jackstands for that operation, I fired her up without the driveshaft in place, and the racket was still there. A local Vette racer told me every tranny is different, and sometimes you even need to balance gear clusters if you're going to run 120 MPH all day. But this happens at 20! I've run Hurst linkage on my Muncie and understand the rattling problem with a directly attached shifter, but this is MUCH worse that that ever was. As a Mechanical Engineer, I just can't believe anyone would design something that would sound this bad unless something was wrong.

Now that I've gotten that off my chest, is anyone aware of a common problem with Richmond 5-speeds that causes undue vibration in the output shaft? I really would like to know what I'm looking for and if I have a chance of finding anything before I tear this puppy out again. That is NOT a fun job. I may even wait until Winter before I go after it, but I'm not sure I can stand it that long. ANY advice would be appreciated. Thanks!

Fevre

Are you running syn lube in it? Might help if not and worth the $10 or so to try.

EDIT: Just notice you said from 'Gurus' but you can still take my advice if you like. :)


[Modified by Fevre, 3:52 PM 7/14/2003]

LT-1 Larry

Yup. I'm running Red Line MT-90 synthetic in it.

WA 2 FST

My Richmond 5-speed has ~1000 miles on it now (bought it new) and it has never had the vibrating issue you describe. I also have a Hurst shifter. I think there is definitely something wrong with it.

My only complaint is that the trans is a bit notchy shifting, but I'm getting used to it.

427Hotrod

They are a little noisy, but not that bad. Mine is an old Doug Nash, and I really think they were building a nice unit back when they were sort of built as a custom unit by a small company. But Richmond builds good stuff overall, so it sounds like something isn't right.


Does it get better in 5th gear? Most of the whine is gone by then, once you get out of the TQ multiplication of going through the countershaft.

Without a yoke in it, does the output shaft wiggle around?

Any chance the bellhousing alignment is way off? What bellhousing scattershield are you using? Mine is a Mcleod and it uses a small alignment ring on the input shaft housing to center trans. Without it, it could be way off. Or it could just be off anyway. Is it the same bellhousing you had in it before?

Any metal in oil?

Most of the noise in mine is at very low speeds (under 20 mph) and it sounds more like an old granny gear trans whining some. No rattle or anything like that. Now my C-4 with the ZF trans sounds like a bunch of marbles in a can when idling!

What did you do for rear mount? You might have driveline angles off. Pretty easy to do when you are only talking a degree or two. That will definitely cause ungodly noises and vibrations. I've seen transmissions pulled and disassembled (with no problem found) because angles were off. You will swear the trans is about to come in the car with you!

I'm thinking you may have to open it back up, but before I did, I'd get a ride in someone else's car to verify noise levels.


JIM


[Modified by 427Hotrod, 5:00 PM 7/14/2003]


[Modified by 427Hotrod, 5:04 PM 7/14/2003]

LT-1 Larry

Jim:

Thanks for the good input. To answer your questions: No, it doesn't get any better in 5th. Third and fourth are a little bit noisier, but it's a different sound. This rattling seems the same no matter what gear I'm in. The last time I had the yoke off, I didn't get any wiggling of the tail shaft. I'm using the stock bellhousing. Besides, I get the same noise with the car coasting in neutral and the engine off, so don't think that's the problem. I also went to great pains to align the driveline components both vertically and horizontally and keep the anglular misalignment to a minimum. That's part of the reason this is so frustraitng to me. I expected a lot smoother running. Also, I eliminated the drive shaft question by running the car without the drive shaft installed. Same problem. Don't know about metal in the oil. Some day when I want to get messy, I'll pull the plug and look at it. Other than verifying that something metal is wearing down, what would that tell me?

Thanks again for the input.

spikezz4

I ran the 5-spd with a 3.08 rear end for 5-6 years. It had to be totally rebuilt after 20,000 miles. Richmond told me that I didn't buy the "bullet-proof" one. It was, however, advertised as such. The "bullet-proof" gears we bought to replace them were an extra $100.

I had vibration, but learned at the end that it was more frame related (rust) than transmission. The Hurst linkage was never very good. The competition plus shifter for both 3 and 4 speeds are better, but we could never figure out why. I'm using the Long shifter on the new 6-spd.

With the upgraded LT-1, you will definately enjoy driving the car much, much more, almost like they should have built it that way in the beginning. Ah, technology.

Sorry I don't have a definitive answer for your vibration problem. Mine cost me the last 5 1/2 years rebuilding a Pro Touring car.

Spike

LT-1 Larry

Thanks Spike. :cheers:

By the way, the first time I drove the car with the new gearing, I said exactly that: "This is the way GM should have built the car in the first place."