Undercar Questions

[rockiemosley]

I just wanted to post a few questions- I had the GTV 2000-1974- in to the muffler shop this morning and they let me poke around under the car with it up on the lift. I know I need to replace the guibo as it has some hairline cracks. Wondering if I should replace the center support bearing as well or just leave alone...it appears to be sagging slightly in its rubber mount, but not very much. Wondering if I should just replace it the same time as the guibo. Also the rear tranny support seems to have seen better days. Any upgraded bushing for the rear tranny mount? As I remember the stock part just has a rubber web with holes supporting the center, seems like a good application for solid rubber here? I had the car back at the muffler shop since I had them weld on a exhaust brace to tranny mount, but since then I get a loud metallic vibration as I wind it out past 4000 rpm. Like the tranny is twisting in the tunnel and vibrating somewhere. So I suspect a bad rear tranny mount. Also, I noticed the speedometer cable comes out of the tranny at a funny angle and you can slide the housing in and out a little, and tranny seems to leak oil at the cable. Im guessing there is some sort of rubber part that I am missing ?

Thanks,

Mark

[Andrew]

1. If the center bearing mount is sagging it is probably a good idea to change it and the bearing. I would not do one without the other. It involves splitting the driveshaft on a taper fitting, so it's not to be done lightly.

2. The giubos often look split; if the cracks are major, it's a good idea. Probably better safe than sorry on it, as if it tears and comes apart, it can really rip up the car, and the driver.

3. There are aftermarket mounts, but they are likely to introduce a lot more vibration into the body. It's hard to imagine how much until you've tried it. I personally would go for a replacement stock mount. For track cars, poly mounts are OK but I wouldn't use one on the street.

4. That's common on the speedo cable. Will it tighten up? Cable housing where it meets the trans might be worn from not being tight. You can get replacements.

Note that almost any work in the trans/exhaust/driveshaft area can solve, or introduce, vibration and noise problems. It's all interrelated. I would replace the donut, center bearing and carrier, and trans mount, and see where you are at that point. While you have the driveshaft off, examine the "ball" on the back of the trans output shaft and its matching bushing in the front of the driveshaft for condition and wear. If OK, put back together with grease, and make sure the rubber sleeve is in there to hold grease in the bushing.

Andrew