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Old 01-07-2009, 02:09 AM   #1
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Default TALL ORDER ON DIFF SERVICE FAVOR

I know this is asking alot but if you have some free time to respond it would be a huge help. I am getting ready to change the factory grease to oil in all 3diffs on my losi 8 rtr buggy. Going to run 5-7-5

While I was at the LHB I asked for some help and the response I got was "Well it only takes me 5 mintues to do each diff" followed by "take everything off radio tray, gas tank, motor, etc." I didnt feel so good about spending nearly $700.00 over a two week span at their store.

I wanted to see if anyone was willing to explain in detail on what bolts/parts to take off to access each diff. This is my first time doing this with no past rc experience and I dont want to do double the work if it is not needed. Other than the manual (which i have) maybe someone has a diagram illustrating the work for each one.

Front: Which bolts/parts to remove? Tricks of the trade to rebuild diff?

Middle: Which bolts/parts to remove? Tricks of the trade to rebuild diff?

Back: Which bolts/parts to remove? Tricks of the trade to rebuild diff?

How long do you think is should take from start to finish. The LHB said 4 to 5 hours if its your first time.

I know this is alot to ask and I understand if I am asking for too much. Thanks in advance though.
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Old 01-07-2009, 03:14 AM   #2
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Changing diff fluid is probably the most time consuming task on a Buggy or Truggy. So don't try to rush do it correctly and your buggy will last a long time. 5-7-5 is is going to be really aggressive probably resulting in a loose rear end. You should be thinking more 5-5-2 or 3-5-2. However I have tried that combo and that's how I and many others found it's to aggressive. You will probably learn more from actually doing 5-7-5 and seeing how the buggy reacts. It's a good lesson to learn so I'm not telling you not to do it. Actual hands on experience seeing it for yourself is much better than someone telling you.

Center diff is the easiest 12 screws total 4 on the bottom of the chassis and the 4 holding the top brace. Then the 4 holding the spur to the diff.

You will repeat this part for all 3 diffs. I take a Tupperware dish and just dump my diff grease and parts in there. with a rag clean the inside of the diff clean the inner diff parts and replace. fill diffs with desired diff oil don't over fill diff oil heats up and expands during use. some people will say clean the parts and diff case with this or that product it's up to you. Really it's not necessary. Have you ever seen a mechanic clean out a diff case with a product when changing fluid or the engine for that matter. They both last hundreds of thousands of miles with no problems. The same applies here.

Front and rear are near identical on front remove top plate on rear remove the screw that secures the chassis brace to the diff. remove 2 front or rear hing pin brace screws and brace, remove 4 chassis screws, 4 small sway bar screws and brace, 4 diff screws.

I did not include any shortcuts to doing it because you need to learn the long correct way first. If you want to speed the process up buy rechargeable screwdriver with torque adj and a set of standard hex drivers. This alone will cut the job time in half. not a drill they spin to fast and the friction they create from spinning fast will melt the plastic.
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Old 01-07-2009, 03:38 AM   #3
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I have a Jammin X1 instead of the 8ight but I would like to share some of what I have learned.

Vladconnery is right about taking it slow. Changing the diff oils ir a fairly simple task but it will not become easy until you have done it a few times. I just started with my buggy this last April and the best tips I can give you is have the manual open to an exploded view near by and set up somewhere where you can lay out the pieces and leave them undisturbed for a while.

While your LHS can be a good resource it sounds that they are trying to get you to do more work than is necessary. Your engine, fuel tank, radio tray do not need to be remove. I find it easier to work on my buggy in three sections and separate it that way. I remove seven screws and the front end is free and it is more manageable than the entire buggy, five screws to remove the rear end, and four screws to remove the center diff assembly. Than as you remove screws to free the differential place them in a manner that will help you remember where they came from. I suggest you do one differential and reassemble that section to the buggy before moving on to the next one.

If in doubt refer to your exploded view, don't be afraid to make notes in the manual to help you along.

When I first replaced the grease from my differentials one of the local racers suggested I use varsol to help clean out the grease, it worked fine; however, the varsol caused the o-rings in my diffs to expand and became a serious pain to reinsert. Also, having spare gaskets to replace damaged/ripped ones is a good idea.

Above all, if you get tired or frustrated walk a way for a while. This is why you need a space where you can leave your parts out. When replacing the oils become ssecond nature you won't need the space or time, but when you are learning it is vitally important. Looking back to the first time I changed oils I am boggled by the amount of time it use take, now if I needed to do it I could probably do it at the track in under 30 minutes for a ll three differentials.

Hope this helps, just remember to be patient and give yourself an out to take a break.
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Old 01-07-2009, 04:06 AM   #4
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Another try is 5-7-2
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Old 01-07-2009, 04:22 AM   #5
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In the manual theres a section that tells you just what you want to do. Step by step for from, center and rear. I would start out at 7,10,3.
Pages 7,8 and 9.

http://losi.com/ProdInfo/Files/LOSB0...RTR_Manual.pdf
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Old 01-07-2009, 04:37 AM   #6
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I have never rebuilt diffs on a losi so I couldnt tell you how to do it but one piece of advice I can give is check the manuel to make sure how much fluid to put in. over filling can cause them to leak. and under filling them can cause them to heat up.. I always fill to the top of the outdrive gear then put the cross gears in then fill to the top of the shafts.. instructions may be different but take your time here.. also I have found that the losi diff fluid isnt the greatest,, seems thinner and doesnt last very long. maybe ofna would get better life.
just a thought
thanks
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Old 01-07-2009, 05:06 AM   #7
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Where did you get the recommended diff weights? If it were me, I'd run the same setup as the race roller and start your baseline from there.
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Old 01-07-2009, 11:18 AM   #8
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Recommended diff weights was from the LHS. Hey thanks for the great advise. This will definately give me a good start. All your help is greatly appreciated!!!!!!!!!!!!!!!!!!!!! Also thanks for your time!!!!!!!!!!!!!
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Old 01-07-2009, 11:39 AM   #9
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Use the same brand of fluid in all three diffs. If you are going to use a setup from losi, use losi fluid. Different manufactuers use different systems of viscosity measurement. 400 in one brand could be 200 in the next.
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Old 01-07-2009, 02:50 PM   #10
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I always replace gaskets every time I change the fluids. Gaskets are cheap.

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Old 01-07-2009, 03:04 PM   #11
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5-7-2
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Old 01-07-2009, 04:05 PM   #12
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You must shop at Hobbytowne
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Old 01-07-2009, 04:17 PM   #13
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vladconnery

How did you know???????????

Its the only LHB that is in close range to me!!!

Whats unfortunate is I am a big proponet on supporting the local buisness. Thats why I bought my buggy from them, I could have saved over $100.00 if I bought online but I was staying true to my belief. The other day when I went in I got so fustrated due to not being able to find a very common part along with the service that was provided. Its like they forgot that I just spent a ton of cash in their own store.

I then told my self screw this I am just going to buy my parts from in the net. They are almost always stocked and I can get it the next day if I want.
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Old 01-07-2009, 04:42 PM   #14
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Because Hobbytowne employees don't know crap in my experience. They tell you whatever they heard and not what they know from experience. Not to mention they generally only carry Traxxas and HPI stuff. Your better off asking questions hear and buying online. Luckily for me 2 of the 4 lhs by me are independents. One being CarolinasRC which is a great place to race and get info and buy parts. Not to mention they stock parts for whatever they sell. All of the guys who work there race as well.

Hobbytowne is the Walmart of RC'ing
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Old 01-07-2009, 04:56 PM   #15
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-dishsoap-

where do u live? and are there any tracks near you that you can go to
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