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Old 12-07-2008, 03:32 AM   #1
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Default over filling diffs?& xray 808 rear diff shimming.

hi guys i own an xray xb808 and started out from new with it with 333 in the diffs 3 front 3 centre 3 rear then went to 555. and it seemed to work for me and the car was pretty good to drive its just that now all of a sudden the car has gone from good to bad it gets real taily the steering seems twitchy and i oversteer a tad and the only thing i have done is to my diffs wich was 5 front 5 centre and droped to 2 rear.

im not sure wheather doing that would effect the car so badly in this way so im wondering if over filling the diffs has a dignificant differance on car handling performance does it effect it that much?

and also to all the xb808ers out there i heard this rear bearing problem people are shimming in the diff housing does it effect performance?
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Old 12-07-2008, 09:51 AM   #2
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overfilling the diffs will cause it them to leak, check and make sure they arent empty causing what you described...
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Old 12-07-2008, 10:51 AM   #3
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if the car starts acting erratic there is a good chance a diff or something is leaking or empty
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Old 12-07-2008, 11:22 AM   #4
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Yes, over filling the diffs can cause adverse effects on handling, and under filling will cause strange things to happen also. Take a close look at your manual, it has a pic of how much oil to put in. Using 5-5-2 or 5-5-3 should be pushy not twitchy. IMO 5-7-2 gets too loose on a loose track.

- One other thing to check would be to check the 19x13 front and rear center bulkhead bearings that hold the pinion gear. Its the one maintenance item you need to keep up with on the 808. Slap a set in every 2-3 gallons, you can get those bearings for $1.00 each at AVIDRC. So at most, its a $4.00 maintenance item, and a small price to pay for some reassurance. Also, Xray makes a new 19x13 bearing that is probably the best on the market for a few dollars more.

- Check the ride height, as the car settles after a new oil changes, or a prolong run on the same shock oil. This car is sensitive to ride-height changes so keep an eye on that as well. The front of the Xray hooks up too much when the front ride height drops too low. If the car feels like its turning on a dime just raise the front up a couple turns on your shock pre-load to smooth it out a bit.

- If it was a sudden change in steering or drive-ability, take a look at your radio settings to make sure you didn't bump up dual rate, speed, EXP, or EPA accidentally. I've done that before, and tried for days to fix it with setup, while my EXP was at 150%..! LOL!

Hope that helps.
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Old 12-07-2008, 09:56 PM   #5
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I had the same thing happen to me & traced it down to outer wheel bearings.They felt fine if you grabbed the wheel & turned ot but when taken out they were crunch beyond beliefe. It happend I think around 2.5-3.5 gallons & was one of those just happened in the middle of the day things with no hard crashes right before. Also remove & check CV joint pins mine wore faster than I was used to with my last car,same story with those bearings. I also use 8x16 bearings on all my diff out drives since I had several sleeves of them from my last car & those last forever with little to no maint. I havent had pinion gear bearing problems yet but have heard some people have,I think they made a running change for later kits though & have made a change in the newest kits again recently.

Carcrazy is correct going thinner in the rear will not make the car over steer out of turn it will make the rear more planted & follow the front tires more,to the point of understeer if you run 1K. If fluid in the front gets low this car will do wierd irradic stuff though but over filling the X-RAY diffs will not have as dramatic effect as say my mugen did since the 808 manual has you fill the diffs to almost completely full once the diff is completed(top of spider gears compared to top of cross pins like most other cars). I routinly over filled my mugen on purpose then it required 4-6 tanks for it to leak down to where the fluid needed to be before the car handled right.

I run 7-5-1 & that keeps the rear planted from corner entry to exit where I can whack it WFO & the rear wont break loose as the front pulls so hard it snapps into a straight line,or as straight as your holding the wheels anyway but it does push a little at turn in wich fits my driving style to a T.
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Old 12-07-2008, 10:16 PM   #6
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Quote:
Originally Posted by butch man View Post
I had the same thing happen to me & traced it down to outer wheel bearings.They felt fine if you grabbed the wheel & turned ot but when taken out they were crunch beyond beliefe. It happend I think around 2.5-3.5 gallons & was one of those just happened in the middle of the day things with no hard crashes right before. Also remove & check CV joint pins mine wore faster than I was used to with my last car,same story with those bearings. I also use 8x16 bearings on all my diff out drives since I had several sleeves of them from my last car & those last forever with little to no maint. I havent had pinion gear bearing problems yet but have heard some people have,I think they made a running change for later kits though & have made a change in the newest kits again recently.

Carcrazy is correct going thinner in the rear will not make the car over steer out of turn it will make the rear more planted & follow the front tires more,to the point of understeer if you run 1K. If fluid in the front gets low this car will do wierd irradic stuff though but over filling the X-RAY diffs will not have as dramatic effect as say my mugen did since the 808 manual has you fill the diffs to almost completely full once the diff is completed(top of spider gears compared to top of cross pins like most other cars). I routinly over filled my mugen on purpose then it required 4-6 tanks for it to leak down to where the fluid needed to be before the car handled right.

I run 7-5-1 & that keeps the rear planted from corner entry to exit where I can whack it WFO & the rear wont break loose as the front pulls so hard it snapps into a straight line,or as straight as your holding the wheels anyway but it does push a little at turn in wich fits my driving style to a T.
7-5-1 now their is one I haven't tried yet... LOL! Would that work on a loose rutted track?
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