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Still have an intermittent vibration in 4th gear. In Turn 1 I can feel it as soon as I downshift from 5th to 4th. Heading in to turn 7 it seems fine shifting from 3rd to 4th but as I accelerate up and in to T7 I could feel it.
On the front straight I think it was fine when going from 3rd to 4th as I accelerated towards 5th, which is weird. Drained the trans fluid into a clean pan, no big fragments or anything out of place. There was also a small amount of ATF dripping from the seal, nothing catastrophic, but unusual.
Going to pull the trans, get the tailshaft housing off and check/replace the output shaft bushing and see if that helps for Hallet.
What else could it be? Hoping I didn't bend the output shaft but that wouldn't that become apparent all the time above a certain speed, as not evidenced by it being fine in 3rd/5th at the same speeds?
Recall that at MSR cresson I had the driveshaft seperate from the rear and bang around, which I believe to have caused this...
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Sorry you are still having a vibration. If you don't find anything consider having someone else drive the car to verify. I'm guessing the vibration must be pretty noticeable if it's in Turn 1 on the 5-4 downshift. My whole car feels like it might explode from the end of the straight till the time you get it braked and back on the gas.
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Yeah, mine was doing that in turn 1, but only when I downshift; everything I've got (play in yoke, vibes on decel in specific gear, seal leak) is symptomatic of a worn tailshaft bushing (which likely happened when the old driveshaft got flung around at cresson). $10 part and an afternoon of work, I'll just do it.
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Pulled the trans out of the car and replaced the tailshaft bushing. The yoke had some play with the old bushing, not so sure if it was bad. I did replace the trans mount as it had a ton of flex in it compared to a new one.
I also swapped the pressure plate before putting it back in, clutch is nice and smooth now, I think I tweaked it when pulling the old motor out of the car and not loosening the bolts in sequence.
For future reference, anyone that wants to do a t56 output shaft bushing:
1. Buy TWO timken/national 5200 seal/bushing sets. You will screw the first bushing up
2. Press or carefully hammer the old bushing out and the new bushing in
3. Use a 3-stone brake cylinder honing tool to open the bushing up just enough to push the yoke in
4. When reinstalling the tailshaft housing, you'll need to wiggle reverse fork slightly to get it all to line up
5. I took my tailshaft off with the transmission out of the car and sitting input shaft down on a furniture dolly with blocks of wood. I think this is the safest way although I've heard you can do this in car. I took mine out because I wanted to swap out the pressure plate.
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Same problem happened again at TWS weekend. Within seconds of the green flag one of my diff-side u joint caps ejected from the yoke, presumably because the clip popped out again. The straps were still on and tight, and one of the two caps was still strapped in place.
Fortunately I had a spare shaft and straps so I threw it on and did plenty fine for the next race, no vibrations either.
The yoke got chewed up pretty good and needs to be replaced. Given that this is the second u joint clip/cap ejection I've had in 2 years, I'm going to order up this Yoke in lieu of an OE GM one. If you compare the two you will see the Yukon yoke has a very pronounced "seat" to capture the u joint cap clips, vs the OE GM one that has nothing:
https://www.yukongear.com/productdet...spx?ProdID=976
http://www.ebay.com/itm/1993-CAMARO-...9V6gE7&vxp=mtr
Hopefully that should prevent the same problem happening again. The only solution I came up with last time was to go from china made parts store u joints to beefy non greasable spicer u joints, but I think this yoke should seal the deal.
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Gotta get on that heel-toe game homes! Cheaper and will last longer.
- Josh
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Picked up another driveshaft from a buddy on my way out from college station. Putting in new U joints and having it checked/balanced and will test fit it against this yoke before installing it all:
https://www.yukongear.com/productdet...px?ProdID=1097
It apparently this style yoke uses a 99-up 7.625 pinion seal, a "triple lip design". I actually haven't had any seal issues in the past, but this is an upgrade over the older "8610" seal most of us have been running.
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I ended up installing that yoke, the grooves are great for capturing the clips and I clocked them to be pointed towards them. The newer style seal is entirely optional; just stuck with the seal that is on my rear end as it wasn't leaking at all.
FYI for anyone rebuilding their 10 bolt, get this yoke!
https://www.yukongear.com/productdet...px?ProdID=1097