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View Full Version : Bouncing In Driveline At 3000 Rpms



toofun
06-15-2006, 05:25 AM
I have a TKO-600 and a 383 stroker motor in my 69 camaro. I have been driving it for about 300 miles now and have noticed a "bouncing feeling in the tranny or drivetrain when Im cruising around at 2500-3000 rpms. It does not appear at idle or if I give it some juice and let it climb. Just when Im crusing around at those rpms. What could be causing this?? All the tranny mounts are brand new. The drive shaft appears to be about an inch or two too short but other than that I dont see any other problems. Could it be the pinion angle and if so, how do I check to see if it right? You physically can see the stick shift bouncing up and down more than usual.

Thanks in advance

Mark
TOOFUN

HILROD
06-17-2006, 07:14 AM
You said the driveshaft is too short. If that is true the yoke will not be riding in the bearing in the tail shaft and will ruin the yoke and will sooner than later hurt the trans. Get a longer yoke or shaft. It is usually under $100.00 to get a shaft shortened. Just get a shaft that is too long to start. Getting a shaft retubed longer can be big bucks. FRANK

Steve Chryssos
06-19-2006, 09:33 AM
Might sound silly but how about the subframe bushings. Vibration is one thing, but bouncing seems pretty radical. Put the car on jackstands. First just the rear wheels (under the axle). Run the car up to 3K and have a looksee. Hopefully the problem will show up even thought there is no load on the tires.

After that, I'd put the whole car on stands--engine off and jack up the trans crossmember to see what if anything moves.

toofun
06-19-2006, 10:50 AM
Well this is what I was able to find out so far, barring aside the info you have already relayed to me.

The cross member I am using is a forte crossmember as seen here http://www.5speedtransmissions.com/5spcrossmember.html. The first hole lines up but the second hole does not, so the crossmember is only being held on with one nut and bolt on both sides. I plan on drilling another bolthole for both sides in place tonight. But even with the setup the way it is I noticed that if I push up on the crossmember it will flex a little bit up and down in the middle. Almost the same distance as what I see in the car. I dont know if it is because their is only one bolt on each side, if it is because the driveshaft is two inches too short, if it is because this crossmember has too much give in it or if it is a combination of all three. Is it suppose to have any give to it at all?? Has anyone else used this crossmember? ANY OPINIONS would be appreciated.

paul67
06-29-2006, 12:08 AM
Extended the drive shaft or you will destroy the trans. And a good chance that it might break the tail shaft causing the prop to fly around which could do a lot more damage.

dhardison
06-29-2006, 04:09 AM
Well this is what I was able to find out so far, barring aside the info you have already relayed to me.

The cross member I am using is a forte crossmember as seen here http://www.5speedtransmissions.com/5spcrossmember.html. Has anyone else used this crossmember? ANY OPINIONS would be appreciated. Mark,

I have the same crossmember and the same problem. Mine doesn't 'bounce' at a certain rpm but instead bounces when riding over rough roads and/or bumps. It bounces enough that I can see the shifter move up and down (more than it should) AND I can even feel it through the accelerator pedal (solid throttle linkage), which can't be a good thing.

I didn't have to re-drill and crossmember mounting holes, but I did have to elongate them on one side. The crossmember has A LOT of flex, which along with a poly trans mount causes quite a bit of 'bounce'. I'm going to contact Classic Chevy 5 Speed and pick up one of their "totally" tubular crossmembers to hopefully eliminate the bounce.

http://www.classicchevy5speed.com/Elite_Transmission_Kit_w_shifter_Xmember.htm

toofun
06-29-2006, 10:35 AM
Hey let me know how that works for you. I am very curious to see if that alleviates your problem. I lenghtened the driveshaft and it is perfect now. But I still get that bounce. This crossmember has alot of flex in it. More than it should for sure. I guess I will wait to hear back from you on how this piece worked out for you. Please let me know.

Thanks
Mark
TOOFUN