modern parts for trx-1 Tranny???

[Lonestar]

Hi Guys

I am in the process of restoring a trx-1 which I bought from a member of this site, and that, to say the least, is in a state that I would be very ashamed of selling to a fellow site member as a "runner" to be honest... I started pulling it apart yesterday and I saw some appalling stuff... some people, I swear... anyway, enough of this....

The question is: which modern (Read: easily and cheaply available) diff parts would be a direct replacement for the trx-1? The one on the POS I bought is shot (Read: main gear chewed, missing belleville, rusted outdrives, melted thrust bearing)? Anything bandit would work, maybe? The rest I have parts for I think...

Thanks a lot,

Paul

PS: Updated topic title to "tranny" rather than "diff" given the turn the discussion takes

[jwscab]

rebuild kit, still in stock, amazingly....

http://www.buytraxxas.com/product_info.php?products_id=606

dunno about the main gear, not in stock there, maybe ebay is your best bet.

the bandit uses a gear diff i think.....so everything is different internally. if the gear has 45 teeth(trx1 gear), it would probably fit.

[Lonestar]

rebuild kit, still in stock, amazingly....

http://www.buytraxxas.com/product_info.php?products_id=606

dunno about the main gear, not in stock there, maybe ebay is your best bet.

the bandit uses a gear diff i think.....so everything is different internally. if the gear has 45 teeth(trx1 gear), it would probably fit.

Awesome - very, very helpful, thanks a lot. Now let's just hope these guys ship overseas...

Thanks

Paul

[bearrickster]

if not someone on here will help you out.

[jwscab]

OK, I found 2 differential kits that traxxas offers, both can have a 45 tooth main gear. Why there are 2, I don't know for sure, I don't know enough about the difference between the applications.

4420 is for nitro rustler

2520 is for alot of vehicles. I'm thinking this is the parts you need. I can't find the part number for just the main gear, but i think they modified the diff a little after the trx1, so it might not be a drop in to what you have, ie, you can't just buy the gear I don't think for your application.

both are in stock at towerhobbies. I would call traxxas and ask if the main gear would fit in a trx1, and if not, if the whole assembly will fit. maybe have the old one in your hand so you can give them dimensions. I know the output shafts are 5mm, almost all traxxas stuff is like that, fortunately. The main gear is 45 teeth, so as long as it's narrow enough to fit in the trans case, it should fit!

whatever you do, make sure you let us know if it works or not, becuase sooner or later, someone here might need this info(like me )

[a01butal]

TRX1 diff gear is part #2725.

[Lonestar]

TRX1 diff gear is part #2725.

yes, that I know, I have the manual in front of me...

Thanks all for the valuable help - after a couple of hours on the internet, 2520 is the correct full diff... Traxxas doesn't ship overseas, but Tower does

Now, a closer inspection of the tranny reveals the idler gear and the top gear are also shot... idler gear I have, top gear is 21T slotted, much harder to find it seems... anyone has a spare one for sale? Part# 2795...

I'm actually thinking about putting rusty or pede gears in my trx-1 tranny, and offset it with the spur/pinion combo... mmmh...

I just spent about 3h today going thru cross reference lists... gotta love "budget" restoration projects bhahaha

Wilco - thanks all

Paul

[jwscab]

probably have to keep your eyes peeled on ebay for the upper gear, however, there is a solution, less than ideal, but.....

21t is a moderately sized 48 pitch pinion gear, If you were to purchase an aluminum pinion gear, and file a groove in the small side, and drill the hole out to the main shaft diameter, you have a nice new upper gear. Just a bit narrower than the idler. you might even be able to use the set screw to tighten it down.

if you want to be really fancy, you can get a metal idler, so you won't wear down the plastic idler with a narrow upper gear.

I went through alot of this rebuilding a blue eagle, I was almost ready to do just this option until I found the right gears.

the blue eagle is pain because there are 2 styles of the same tooth number gear, with different diameter diff ball pattern, so i had to buy both to figure out which one was right.....ugh.

[markt311]

I have a top gear you can have, PM me your shipping info and I'll get it out by Friday.

[Lonestar]

I have a top gear you can have, PM me your shipping info and I'll get it out by Friday.

Mark,

you are outstanding - I thought about this restoration all nite wondering if this was worth it at all and I was ready to chuck the pile-o-parts on evilbay, but you just made me change my mind.

PM coming to you - this is MUCH appreciated. Thank you.

Paul

[Lonestar]

Mmmh I like the slotted 48P pinion idea too, but this will have to be made in due time... I have to race this car in the vintage class in early march

Thanks all for all the ideas and the help!!!

Paul

[Lonestar]

I also saw that the stealth diff gears are 45T too... the inner bearing would be different, but the gear could be bored out to 8mm... anyone has ever tried this?

Paul

[markt311]

[quote="Lonestar

Mark,

you are outstanding - I thought about this restoration all nite wondering if this was worth it at all and I was ready to chuck the pile-o-parts on evilbay, but you just made me change my mind.

PM coming to you - this is MUCH appreciated. Thank you.

Paul[/quote]

No problem, just repaying some good karma I recieved from a few members of this forum.

I never thought about the stealth diff gear idea, anything is worth a try. Just remember the diff ring diamater might play a role in how that works out too.

I always thought swapping a complete stealth tranny would be an easy fix but I was always hesitant to drill any more holes in my chassis. Plus changing the axles and carriers.

[jwscab]

as Mark said, you'll have to watch the ball diameter, but that is a great thought!

if you have taken the diff apart already (I'm guessing, based on your descriptions) take a look at how the gear is molded, does it have an offset, like, does the center of the gear actually 'sit' in the center of the gear? I'm pretty sure the stealth has no offsets, so it's probably OK as long as the balls line up somewhere on the diff rings.

I would also ream the hole out to the right diameter, to keep it concentric, and close tolerance, as well.

keep us updated!

[jwscab]

here are pics of both. they look damn close! The associated gear looks a bit wider, but you could sand it down to the right width pretty easily......just have to use the right balls, hopefully, they are the same size, 3/32 vs 2.4mm(same), dunno for sure....doe the traxxas one use 3mm balls?