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Team Losi XXT upgrades... now broken

Old 12-26-2019, 05:26 PM
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LosiFopar
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Default Team Losi XXT upgrades... now broken

So Iíve had this Losi XXT truck for the last 20 some years and replaced things as needed. The truck has held up well to some sever beating over the years (not the body, had to replace that) so when my 13 year old expressed interest in RC cars I got it out and dusted it off. We ran the old brushed motor around a bit and then bought a new sidewinder 4 brushless kit and a Venom 4000 20c battery. Swapped in the new stuff and 5 seconds of insanity later it chewed up the plastic rear diff. I figured someone has done the same and might have some suggestions as to upgrading the transmission. The local store ordered a new gear (RRP9404 Ball Diff Aluminum) but said it would take a week plus to get here. So I called around and didnít have much luck finding anyone who could tell me if there were any replacement gears or transmissions that we could use. Any suggestions?

Thanks!
Old 12-26-2019, 09:49 PM
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LosiFopar
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Correction itís a Castle Sidewinder 4 brushless kit. I forgot to say ďcastleĒ Iím sure you all figured that out.
Old 04-12-2020, 06:35 PM
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jmcbrayer
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Were you able to find a metal diff or did the RRP9404 Ball Diff Aluminum work for you? I'm in the process of converting my XXT to brushless also.
Old 04-12-2020, 07:24 PM
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They didnít order the correct parts for the xxt transmission and no luck finding anything to help at the hobby store. So I turned to ebay and bought a TLR 22 stand up transmission and cut apart my XXT transmission and added the bearing housing to the TLR 22 transmission so I could still run the xxt out drive in the newer transmission. (TLR 22 out drives were too small and too short to accept the xxl axles.) I also ordered a stand up conversion kit for the TLR 22 and used some of the parts to modify a mount for the transmission. So yes I was able to get it to work but it was a lot of custom Dremel work to make everything fit. We also detuned the it to 75% as we still were testing with a plastic composit diff gear from a TLR 22. It works but our only problem now is it keeps unthreading the diff screw. No matter how tight I get it eventually it will spin free and then no drive. I believe the locknut is damaged and I was thinking of adding some Loctite to it but I havenít pulled it back apart to try that yet.
Old 12-02-2020, 08:58 AM
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Mattb114
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Are you still having issues with your XXT transmission? I recently did a full restoration of my XXT and installed a Sidewinder 4 & 4600kV motor. On 3S it was pulling wheelies on the sand. Super awesome.
I had the same exact problem: the plastic diff gear P/N: A-3076 doesn't fair well with brushless torque

Some things to consider:
  1. What grease was used in the transmission?
    • Polymer gears can be incompatible with traditional bearing grease. It can, in some cases, prematurely weaken the gear.
    • Use silicone-based lubricants as added insurance.
  2. Was that the original gear?
    • I found that plastic over time (20 year range with the XXT) generally develops stress cracks. Its only a matter of time until it fails, especially on pavement.
  3. Make sure your slipper is set properly for street use. It's your saving grace.
  4. Pull the pinion off the motor and do a torque calibration in Castle Link. I have my XXT torque control set at 50% to lower transmission abuse.
Here are some things I found along my quest of fully restoring my XXT and will probably be very useful for you or anyone else doing the same.
  • The VintageLosi XX-T forum is really useful for getting P/N's and looking up assembly procedures.
  • Valkyrie R/C Motorsports is the best source to find classic XXT parts. I was able to find that transmission gear from him a few months back. He has a ton of stuff.
  • If you want a factory new body shell, Team BlueGroove on eBay makes the one and only replica of the XXT P/N A-8016. Its the best you can get.
  • For graphics, Nate at MCI Racing is the best place to go. Fantastic dude. He will hook you up with whatever you need. He re-produces all the XX-T graphics!
Paints I used:
  • Tamiya PS-1 for the white
  • Tamiya PS-20 for the Fluorescent stripe
  • Tamiya TS-19 backed with TS-14 for blue strip
  • Tamiya PS-34 for the red/Wheel dishes.
***Side Note*** I used the wrong paint line for a few steps. The TS series is not intended for Polycarbonate bodies, rather the PS series is. Make sure you use the right paints before learning the hard way like I did. Paint chips.
Best of luck!
Old 12-13-2020, 04:52 AM
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hi losforpar i have alot of losi parts for losi xxt ,, xxx xxxt the trans are the same and have lots of nylon delrin gears internal and external i have a i know a complete transmission fits xxx and xxxt if interested ok mugey
Old 12-15-2020, 08:15 AM
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Bdon02
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Originally Posted by mugeyman View Post
hi losforpar i have alot of losi parts for losi xxt ,, xxx xxxt the trans are the same and have lots of nylon delrin gears internal and external i have a i know a complete transmission fits xxx and xxxt if interested ok mugey
I'm looking for the small thrust bearing and the foam seals. Among other things.
Old 12-15-2020, 03:42 PM
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i will look for the thrust bearing on trannsmission and foam things tomorrow ok p m me you info ok mugey
Old 02-15-2021, 04:51 PM
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Jims68
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Default A-3076 upgrade

Does anyone know how to upgrade the trans on my xxt truck or get a A-3076 diff gear? Mine broke a couple of days ago.
Thanks for any help.

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