# Losi Micro-T Transmission/Differential problem found



## Hatchetman86 (Dec 27, 2008)

Hello all, I am new to the forum but have been in the RC hobby world for over 20 years. I have been out of the scene for the past 5 or 6 years and stumbled into the add for the Losi 1/36 scale Micro-T truck line and just bought a handful of them for me and a few buddies to toy around with. My sealed garage floor wasnt the best surface for the Desert Truck I got as any more than quarter throttle would just spin the tires lol though I was able to jump it a few times and for its size it does pretty well out of the box. It had a pretty annoying issue so I looked into a bit more and found what appears to be a design flaw or oversight-maybe in the gearbox and differential area. When driving the truck and letting off the throttle quickly the back end wants to kick out and slide a bit like you hit the brakes. After a quick look I realized the differential is not working at all because it is bound up! Measuring all the parts with calipers there needs to be more clearance between the diff bearings and trans case and when the case is tightened up the diff binds but works freely if leaving the screws loosened up a bit. I bought 6 trucks and they are all the same, the diff is bound up and also because of these there is extra drag on the trans so essentially it is like hitting the brakes as it comes to a stop so quick. A few of these trucks are for a good friend of mine who is a machinist so we are going to play with the one in my truck later and try to make a little more room for the bearings. The trans case halves wont pull together with the diff in place because there needs to be at least .004" more side room which doesnt sound like much but because of the design of the diff the trans case holds the diff together. Im sure someone was sleeping on this little attention to detail and most people probably dont even know it isnt work right but I plan to correct it and just wanted to share this to anyone else who either has or is thinking about buying a Micro-T

Dave


----------



## mini_racer (Oct 28, 2008)

No biggie, it's that way with many of these smaller gearboxes - and the primary problem is that people overtighten the screws holding the halves together. These cars/trucks are teeny-tiny and don't need the manhandling of the screws that guys so frequently do to them.

My advice, tighten until snug (just snug, not tight) and back off 1/4 to 1/2 turn. It still keeps the diffcase halves together as they should, and it keeps the gearbox on any of the mini's from binding up.

Enjoy :thumbsup:


----------



## Hatchetman86 (Dec 27, 2008)

I tried backing out the screws with the trans out of the truck until it was better and they really had to be backed off to make a noticable change. Also because of the lower holes that have screws coming up from the chassis it wanted to pull back together. We ended up using an end-mill that was the same outer OD of the bearings which was .235" and turning it by hand to remove a small amount of material on the trans case halves and that took care of it. On one of the other trucks the diff did loosen up a bit after a lot of full throttle use so maybe the others will as well and I jumped the boat too early lol!


----------

