my buddy just gave me a e-maxx 3906 i wanted to know whats the difference between the 3906 and the 3905 and are all the parts compatable

Here, you can find out for yourself.

http://www.traxxas.com/products/trx_electric.htm

They have exploded views with part numbers for every vehicle.

u can convert it too 3905 its alot better.,

If you check the exploded views, I think the major difference is the whole chassis and complete driveline. F/R bulkheads, shock tower and body post, A-arms, bumpers, wheels and tires can be intechanged between the two.

The 3906 has a rep for being easy to roll over when turning. When I got a used one, it was hard to drive cause it was so easy to roll. I went on eBay and got 3.3 bulks, knuckles, tbs, upper and lower a-arms and drive axles. These are direct swap outs, but it needs to be done all at once cause the a-arms are longer and the axles won't fit the stock knucks either. Sounds like a lot, but seems the 3.3nitro stuff sells cheaper than the stuff for the 16.8 Emaxx and its the same. I did upgrade to 16.8 diffs since the ones on mine were prety shot and were both clicking when I got it.

Its drives like a diff truck now, much less tendency to roll over with the wider suspension. 3906 can still be a lot of fun with some upgrading.

I think the 3905 is longer and waterproof? don't quote me on this

im not sure if it longer but it is water proof

Yes it's longer (+1.275")

I wonder why they got rid of the 3channel radio and 2 speed transmission with the 3905. Seems like it would be a fun feature.

i like it without a 2 speed tranny i want all the power instant instead of waiting until it shifts

1st gear (3906) is a joke - all it does is wheelie. Its been months since I had mine in 1st - just not needed. BTW - it doesn't shift automatically, there's a shift switch on the TQ radio - its shifted by a servo, not some kind of centrifugal mechanism like with a Tmaxx. Thats what the 3rd channel is for.

That may be part of being brushless ready - my G2R and FLM Emaxx are both single speeds (GM conversion).

i just got a mamba monster for my 3906 what do i need to upgrade so it wont break on me i ordered the 3905 rpm arms so that means i need the same 3905 axels and turnbuckels right. what can i do to the trany to make it stronger

You'll need the 3.3 knuckles too - the 3905 or 3.3 drive axles use a diff knuck arrangement, brgs are diff and the TB attachment is diff as well. I don't remember if these will work with the black 3906 bulks - think they won't, theres a raised boss in teh plastic around where the drive axles go that won't let you get the drive pins in. I changed to the grey 3.3 bulks when I converted mine.

You'll need to upgrade idlers in the trans, stock nylon won't last one run. You need to replace the flimsy roll pin in the top shaft that secures one of the gears as well. Its a lot easier to do before you shear it off that to fix it after you've sheared it off! I made a pin from a piece of L wrench as most do. Run the trans in 2nd, theres no need at all for 1st.

RC Monster has good idlers, I'm running UE, but they prob are not available anymore.