ls1247

iTrader: (2)

After 20k miles, looks like my Creative Steel Transmission mount is going south....well don't see how to post pics from iPhone but the mount is separating, there are no readily available substitutes for it and I didn't keep the stock mount like an idiot.

So it looks like ill be crawling back under this freakin car again once I get a suitable replacement which I think I'll build myself using a mount out if a 78 Chevy pickup that cost 8 bucks and they have on the shelf all day every day.

Of course this means canibalizing my $50 CS mount for the mounting hardware but what's worse, climbing back under the car yet again next week or eating $50 on this mount that I won't be getting back and getting this fixed once and for all today!!!

Rant.... Sorry.

tommycompton

iTrader: (1)

At least it's the easiest of mounts to get at.

ls1247

iTrader: (2)

After DSS told me that some of my vibration problems could be mount related, i went looking for another solution. Bio428 has been kind enough to send me his stock mount but it won't be here until tuesday and after finding out my driveshaft vibrations were more than likely caused by yet more mssing parts, i decided to put the CS mount back in it, feeling confident that it would be ok.

But, just for curiousty sake, i bought the old tried and trued GM mount that was in service for probably 30 years and cost me a whopping $7.38 just for the hell of it.

So i go to put my driveshaft in this moring and find this little surprise....the CS mount is delaminating and the GM universal, we put it in everything that moved in the 60's 70's and 80's is a deminsional match for the CS mount.

Therefore, I'm hacking the CS mount up for its mounting tabs and welding it them to what I feel even more confident with and calling it a day because I need to drive my car Monday, not Tuesday, next week or next freaking year.

If anyone has constructive crisitsm other than I'm a freaking idiot, fell free to chime in. It goes under the knife at high noon, EST.

Sick of f****** with it.

voodoochikin04

iTrader: (3)

Why not find a mount from a car that uses this transmission.. Also my cs mount is pulling away from the edges of the steel... But was told it would be fine. Also.... Welding on the new mount, won't that cause to much heat and mess with the rubber?

ls1247

iTrader: (2)

We'll find out but I'm not thinking ill see little more than superficial outer edge meltage.

the mount may very well be ok but after dissecting I couldn't confidentially say it one way or the other. They aren't open, I'm out of time and the transmission could stand to be lowered some anyway and i'd rather lower it with the mount than to stack washers under the Crossmember. With this mount, I'll lower the trans about 1/2 inch which will improve my driveline angles.

Using a mount designed for a t56 is a stroke of genius but I think I lost any genius I had on my last trip to DSS. Have you compared any other mounts to the v1? The factory mount is $526, the revshift insert is too hard and the CS mount too high from many reports and my own experience. A different mount might make a good compliment to your driveshaft.

Mount disassembled, headed for lunch.

voodoochikin04

iTrader: (3)

Here's the problem.... The diff sits up higher than the trans output shaft... The stock driveshaft comes out level with the trans until the carrier...then it heads at an upward angle to the diff. Your one piece should head at the same upward angle from transmission to diff... Lowering your transmission will effectively increase your driveshaft angle...not level it out.. :/

ls1247

iTrader: (2)

According to everything I've researched for a 1 piece (with u joints) to function properly the shafts need to be parallel with each other irrespective of which end is higher or lower than the other. While I've been told this shouldn't be a problem running cvs, optimizing it can't hurt.

According to the digital angle gauge I have, lowering the trans somewhere close to an inch will get me there.

Beyond that we don't know the installed heights of the various different motor mounts we have to choose from. Because I measured it, I can tell you the Umi mounts I put in my car lowered the engine a 1/4 over the completely blown out factory units that were in it. No telling where the engine was intended to sit but needless to say, it isn't there anymore.

Also, there have been many reports of people lowering their transmissions and getting better performance out of it.

Thanks for making me think about it!

voodoochikin04

iTrader: (3)

Even with the different motor mounts.. Yours trans should still be lower than the diff... So lowering it more doesn't make sense. And it doesn't make sense how your trans could be higher than the diff, to need lowering. Also you angle gauge could read different angles and even level...depending how you have your car jacked up or if the lift is lifting equally. Getting the gauge to read level or 0... Doesn't mean the shaft will be level when the car is on the ground. :/

ls1247

iTrader: (2)

If you say so I'm fine with it. But what you can't seem to visualize here is how the height of the motor affects the angle of the output shaft in relation to the pinion shaft.

The only way to change the angle of the output shaft in the direction needed to equal that of the angle of the pinion shaft is to lower the transmission, raise the engine or shim the rear of the cradle. Don't have much of a way to raise the engine and shimming the cradle down in the rear as much as would be required would could start affecting how the car drives...maybe. If you don't understand this, I don't know what to tell you.

The car could be standing on its nose and the angles would still be relative to each other. Again, if you don't understand this, I don't know what to tell you.

bmylez

iTrader: (3)

I'm sure CS would've replaced the mount for free, but I'm guessing you weren't interested in that. And that's crazy; I never realized how much the stock mount was. It's even $313 on GM Parts Direct.

ls1247

iTrader: (2)

CS would make the mount good if indeed there was something wrong with it. The mount didn't look right, its Saturday so they aren't open and I'm in a borrowed shop working on a car that I have to drive Monday to go to work in because I've already burnt up 2 vacation days in one week working through someone else's screw up. If CS has cosmetic issues with their mounts delaminating, then they should post up info to that affect so that guys like me who are in a bind don't take a sawzall to it.

BTW..voodoo, if you posted about your previous experience with this, I must have missed it. I try to document these kinds of things for the rest to see but somehow I missed your post.

I needed a lower mount, maybe not because the CS mount is too tall but my UMIs are too short which is pitching the transmission output shaft up too far. It would be interesting to see how these angles look with a set of their motor mounts.

Becker

iTrader: (4)

Im along to see some results. FTR I am running UMI motor mounts, a CS transmission mount a 1 pc DSS w/ 2 CV joints into a stock Getrag with cradle bushings and diff bushing.

The vibration (if any) that I feel when driving it doesn't sound near the same as all others have said so maybe I am missing it or am lucky to not have it.

So far though it feels fine when I drive it everyday so for now I will just keep reading.

ls1247

iTrader: (2)

Except for vibs transmitted by the UMIs, the car is smooth as silk to 110. Ran out of room or would have gone harder but that's enough for now.

voodoochikin04

iTrader: (3)

Glad it worked out for you... I'd expect to see some issues with other things if your motor mounts are lowering your engine that much. :/

ls1247

iTrader: (2)

At the end of the day, I think you and I were talking about 2 different things.

For a drivehsaft to be smooth, we need to look at 2 different scenarios at the same time...the working driveshaft angle and pinion angles.

You were talking about the working angle which is the angle of the driveshaft itself and from what I can tell, on a 1 piece with u-joints, the closer this angle gets to 1 degree the smoother it will be.

I'm talking about the angles of the pinion and transmission shafts which is something entirely different and these need to be equal for a u-jointed driveshaft to be smooth. Frank at DSS explained that u-joints don't spin at consistent speeds by design, constantly accelerating and decelerating, and this speed is dependent on what angle they are sitting at. If they sit at different "pinion" angles on either end of the shaft, they don't spin at the same speed and they fight each other causing vibrations.

As the name implies, CV joints (constant velocity) turn at driveshaft speed regardless of what angle they are sitting and therefore work in harmony no matter how unmatched the pinion angles are.

You were correct in saying that by me trying to improve my pinion angles I was upsetting the working angle of the driveshaft but from what I can tell, the pinion angles are more important in a u-jointed driveshafts performance than the working angle is when it gets down to it.

Ultimately, you would like to optimize both of these but I'm coming to the conclusion that on this car, that may not be possible with some or all of the different motor and transmission mount combinations we have to chose from. I may be wrong but I'm beginning to believe that this platform may not have been originally designed for this powertrain combo and building the first gen V was a bit of an after thought. Shoving a big engine and transmission, although they fit, in a car that was originally designed for something a little smaller means we don't have much room for error or adjustments......

Apparently, the 2 piece shaft makes it easier to compensate for both of these scenarios and apparently in a 1 piece you need CVs to do it.

As far as what the driveshaft is made of, the lighter it is the longer it can be.

Does a 1 piece shaft with u-joints equal trouble in this car?

ryridesmotox

Just a thought. Have you go e over and dou me checked everything? I mean, you are having some serious issues with this stuff. Could you have missed something? I'm not trying to be a dick and call into question anyone's ability here. It just seems like a few things localized to one area are having issues.

Vcaddy71

iTrader: (2)

Mine is with an 8.8 kit and it has one CV and one u-joint and so far I haven't been able to eliminate vibration completely. Unfortunately dealer broke my radiator and so haven't been able to continue working on it. While I understand the CV is supposed to be able to function in any angle, and a dual u-joint should have equal angles, I haven't found any info on what the ideal angle of a single u-joint is.

ls1247

iTrader: (2)

I think the theory is that 1 u-joint and 1 CV can live in harmony becuase the CV can match whatever the u-joint is doing. If you got the shaft at DSS, I would call and talk with Frank.

07CTS-V

iTrader: (6)

Same here. I found that it was a combination of things. The trans output angle and the pinion angles are not equal and opposite and the driveshaft length is such that the CV is at the far end of it's range. I made a shim to essentially put the CV into the center of it's range and it took care of some of the vibration. I have not had a chance to mess with the angles yet.

I did however install a stock driveshaft with the voodoochikin04 drilled 50a poly center bearing and there are absolutely no vibrations. Becuase of this, I am leaning towards giving up on the one piece driveshaft.

voodoochikin04

iTrader: (3)

Now if only I could source 1000hp+ internals for the 2 cv's on the stock shaft.... and with an adapter from the 8.8 to the stock driveshaft... winning ticket!