LadiesFirst

Good evening, all:

I have posted this note under Electric Offroad, but got only one response, so thought I'd bite the bullet and post this here too so some of the northwest guys who have run Losi in the past might see it.

As some of you know, I have been driving Losi trucks for years and can completely rebuild them with ease. I have a XXXTCR, an MF2 and an MF1. I am working on the Gen 1 transmission for the MF1 as that truck is my backup for my Christmas truck body OR when I have to run slicks. The Christmas body won't fit on the CR as it is actually a Double XT body. The MF1 has been sitting for about a year, with short runs here and there.

I have been rebuilding these transmissions for years, so it's not like I'm a newbie, but I have run into a problem that I can't find a solution to. First off, even though I know in the past we were not supposed to use motor spray to clean out the transmission case and gears, this one was so dirty that I did use motor spray. In my defense, I had heard that it wasn't an issue anymore. After cleaning it out with motor spray, I wiped it down thoroughly and replaced the plastic gears. I cleaned all the bearings, cleaned the teeth of the metal top gear and also removed the top gear and cleaned under it, including the bottom and top bearings and the housing beneath it. I also replaced the plastic spacer. I made sure that the top gear seated properly in the case. Once assembled, everything spins very freely until I put the slipper plates and pads back on and tighten down the slipper nut. Oh, and I also replaced the two outdrive bearings (with used, but good ones). I also do NOT snug the case too tight as I know it tends to bind if you get it very tight at all. When I put the slipper plates, pads, spur, spring and nut back on, it binds so bad it is extremely hard to turn. The slipper plate is NOT rubbing on the motor plate or screws. Even when I loosen the slipper nut it is still hard to turn, plus when I completely remove the slipper hardware, it then CONTINUES to be very hard to turn - like it is binding. Again, prior to putting the slipper parts on, it spins very freely, fully assembled otherwise. I keep checking to make sure the top gear is seated properly. Also, the top gear shaft turns straight and is not bent. Everything appears to be the way it should be. I have even applied pressure to the clutch plate that is mounted next to the motor plate without the other hardware and it still turns freely, so it's not catching there. It seems to me to be somehow related to that top gear position. Could the motor spray have "softened" the case too much? I have used the spray in the past with no trouble.

Can any of you former (or current XXXT) drivers give me some advice on this? I don't know what I am missing here and I generally don't have any trouble with Losi transmissions. This is a backup truck so is not my main driver, but was my "oval truck" in the past. Prior to taking the transmission apart initially, it was spining very freely, it was just very dirty, and my original intent was just to clean it up - until I started having all this trouble.

I'd appreciate any help on this. Thanks guys!

TQRC2

Diane,

Dave and I will be at the track this saturday if you can bring it out we'll be happy to look at it. I'm sure it is something simple but without seeing it it's hard to tell.

LadiesFirst

Thanks, Gary. I appreciate that, but I would think you'd be busy wrenching on your own stuff to dial it in on the new track. When you say Dave, are you talking about Dave Gullickson? I have been asking him questions lately and hadn't wanted to keep bothering him. But if either of you can look this thing over, I'd be very grateful. Never had this happen before.

wolfman864

did you forget the spacer on the input shaft? If so you should be able to use a spear bearing to resolve the issue.

Flakfizer

thats what i was thinking . . the crush tube on the top shaft. . .

LadiesFirst

I was wondering about that tube myself but it is new so it shouldn't be "giving in". In the MF2, I replaced that spacer with a bearing, the wheel bearings fit perfectly there, but in the Gen 1 transmission, I THINK the wheel bearings are too big. I thought I had tried one before, but I'll check again. It's been a long time since then. But the spacer is thicker than one bearing but may be thinner than two bearings. I have some stuff I have to get done today, so I may give it a try later today. But what baffles me is why a new spacer would be "giving in" like that when they never have in the past. I appreciate your suggestions. Maybe if I get the time today I'll search around for a couple of those bearings. Thanks!

wolfman864

from what I read on the xxxsct trans (same as the MF) is to use an extra bearing the same size as the input shaft plus a small shim or two as needed.

LadiesFirst

I tried that too tonight before I got on here. I tried 3 bearings (altogether), then two with a smaller spacer. Even had a little bit of in and out play (just as it is with the stock spacer), but when I put the slipper hardware on, it seized up again, and there is no play in and out whatsoever, almost like everything is collapsing. After an hour and a half of trying everything I could think of, I said "screw it", and robbed the transmission off of my spare CR - my original one. Glad the went back to the Gen 1. I don't like to do that, but will do it for troubleshooting sake. I still want to get that other transmission working though as I don't like using my older CR as a parts truck, but I've had it for now. I'm sure, as Gary says, that it is something small, but I really am beginning to wonder, as unlikely as it sounds, if the motor spray "softened" up the transmission case, although I have used it before with no problem. I don't want to buy a case unless I have to. Later I may just take the guts out of the CR transmission and put the MF1 stuff into it just to see. If that works, then I will definitely buy another case for it, as I don't using my original CR as a parts truck. Right now, things are a little tight so I don't want to buy anything that I don't have to. If it works, then I'll be more than happy to buy another case.

I am still going to go to the track tomorrow as Gary Culp has offered to look at it, and I really would like his input - and Dave's too if he is there. Not sure if I will race though. It will be a last minute decision. Thanks for your suggestions - I do really appreciate them all. You never know when someone will hit on the right answer!

wolfman864

I don't think the motor spray should attack the plastic, maybe it's nitro cleaner? I bought Scott Smith's XXX-SCT and I went through at least two cans of spray cleaning/replacing EVERYTHING and don't have that problem.Maybe a shim or two is on the wrong side of the gear and doesn't show till after everything is tightened down??

LadiesFirst

Thanks, Wolfman. I may experiment with that then. Today I'm off to the track to have Gary look at it. He may say the same thing, who knows. You don't usually need shims in that trans, but who knows, things do change. Thanks again. Enjoy this beautiful weather!

LadiesFirst

For closure sake, I just need to post that the solution was found on this transmission. A friend of mine who is a "Losi guru" found it quickly. The top bearing was seizing under load - toast. I had checked the bearing, but the way I was doing it made it feel okay - I press it between my fingers and turn and it felt smooth. He told me to hold it between two fingernails (but I keep them too shorto) and try to turn the ring, and it was very stiff. So now I carry a pencil or a bearing tester with me. So simple, yet so evasive if you don't test it correctly. Lesson learned. It is great now. Thanks everyone for your suggestions!