I was on another site but decided to start a thread here, seems like the E-Maxx section is still alive.
A couple months ago I went into a hobby shop with my son to buy an RC. I was originally looking for a DuraTrax Baja Bug, I have a 69' Baja and my son wanted a small one. The hobby shop didn't have any in stock and the hobby shop guy didn’t seem to like DuraTrax, so I decided not to get one. Not wanting to disappoint my son by not getting him an RC that day I started looking at other vehicles. My son noticed a monster truck and decided that was the one he wanted. It was used and the price was cheap. I bought it not really knowing what I had bought I was a complete NooB. After doing some research I found that I had bought a 3906. I was a little disappointed that the hobby shop didn’t let me know what model it was but there was nothing I could really do about it since they were selling it on consignment. The first run my son hit a railroad tie in my backyard and broke a bulkhead, this one incident started my obsession with making the 3906 strong enough and stable enough for him to be able to handle it better and not have it breaking all the time. I have learned so much from forums like this one and from YouTube videos. Anyway here it is, if anyone has any suggestions that would make this Emaxx better post it I enjoy input and I’m still kind of new to RC.
Castle Creations motor fan
Brushless Differentials front and rear. 100k diff. lube in front, 100k diluted with 30k in the rear
Hobbywing SC8 WP esc
Kershaw Designs HD Slipper Spring
Lunsford titanium hinge pins
Newer Emaxx Axles/Carriers (Front)
Newer Emaxx steering with servo saver built in
Proline Maxx Masher Tires
Robinson Racing Double-Disc Slipper
Robinson Racing 66t Spur / 22t Pinion
RPM Arms front
RPM Bulkhead Braces (Emaxx came with these already installed)
RPM Center Skid
RPM Shock Towers
RPM True-Track Rear
RPM Revolver StableMaxx Wheels
2 SPC 2s 5000mah 30c lipos
T-Bone Racing Bumpers front and rear
Traxxas 2.4GHz transmitter modded to 3 channel and waterproof receiver box
Traxxas Aluminum Bulkheads front and rear
Traxxas center CVD’s (had to use MIP cups because of the shorter pinion in new differentials)
******* 2100kv 4-pole
I also have a new set of Unlimited Engineering steel idlers to install just waiting for stock idlers to fail.
I didn't paint the body I bought it this way. I am not artistic at all, no painting skills. The body still needs to be lowered a little, just have to cut the bumper slots in the body.
This is what it looked like with the 775:
Brushless (Since this picture I have added a Castle Creations motor fan and reinstalled the dust cover):
Maximizer Beadlock wheels. I absolutely dislike gluing and removing glued on tires. Also I stripped the inside of one of my RPM Wheels.
Extending the chassis. I want to do this just to have a bigger choice of bodies.
Last edited by Zane_Grey; 05-09-2013 at 10:36 PM.
The ramp I built with my son, it is 3ft high and 3ft wide:
Last edited by Zane_Grey; 05-09-2013 at 10:24 PM.
Nice Truck! Your son's a lucky kid to have you for a Dad .
Looks like you have everything that's needed.
I installed one 3908 diff in my 3906 and it didn't need the longer CVD cup because of the way I locked it into second gear. When I install the next diff I have Revo extended cups. I also have a couple MIP cups so I'll have to see which fits best. Thanks for that tip .
Thank you, I spent a lot of time researching when I put the truck together. My son loves it but I made the mistake of spending to much on it, now I have to wait to get my own RC. He does let me drive it most of the time though.
Did you use the newer output shaft when you locked yours in second gear? I know the stock shaft is 67.6mm long and the newer shaft is 70mm long which would help with the shafts being to short. I have been working on putting the newer shaft in mine but I want to keep first gear. Everything so far fits but the selector gear is smaller and I haven't tried to see if the newer shift fork will work. The Revo extended cups wouldn't work for me they are 19mm long which is only 1mm longer than the cups that come with the cvds, the newer pinion is 2-3mm shorter. The MIP cups I ended up using were 1495, they were hard to find. When I finally found a site that had three in stock I ordered all three. I do have to set the grub screws near the end of the output shaft for them to work though.
I finally got the banker (my fiancÚ) talked into letting me order a set of Maximizer beadlocks. My son picked out the green ones! I don't know if they will look good but he has a good eye, they were the cheaper ones! I will probably end up dying them black. They are 17mm hexes so I am also getting a set of adapters.
I also finally decided to sell some of my left over RC items on Ebay. If all goes as planned I am going to use the money from the sales to purchase a monoblock chassis extension from Unlimited Engineering. I know it would be cheaper to just get the required items I would need to convert to the newer chassis type, I have everything besides the newer transmission, center shafts, and a body. I just like modifying the 3906 to make it better. Its a lot more fun for me to have to figure out how to make things work.
I will post pictures once the rims arrive.
Last edited by Zane_Grey; 05-14-2013 at 08:01 PM.
Thanks for the heads up on the output shafts lengths. I used the stock shaft but those few extra mm on the newer shaft should make it fit even better. Your talking about TRA3994X...right?
HPI makes some 17mm aluminum adapters that should work.
That's an impressive 3906 you have Zane G! I too have an original 3906 that I recently went thru replacing all the ball bearings throughout the entire truck, rebuilt front/rear diffs, with Maxx Masher tires like yours & bought 2 new stock Titan motors. I finally tried my pair of Thunder Power 2S 5300mah 65C lipos in it & was really happy with the results! But I don't know how long the stock Titans will hold up to the continuous lipo useage. I saw that the top speed your truck hit was 38.7 mph! NICE! Is that . . . 2100kv motor an 8th scale motor? Are there any other specs that you can give me on the motor? Price...4 pole...sensored or sensorless??
VERY cool build man!
Edited for language abuse. If you see a starred out word in your post, you must edit it out to avoid earning warning points; this also applies to product names that have been blocked by the filter.
Last edited by cooleocool; 05-16-2013 at 06:39 PM.
Sorry I took so long to respond to you guys I've been boiling my tires. The new rims are supposed to be here tomorrow, hopefully this will be the last time I will have to remove glued on tires. I just wish that I could find my gloves, boiling water doesn't feel so great on the hands!
I don't know how you locked your transmission in 1st gear so I am not for sure if it will work for you. If you could post pictures I could figure out whether it could be made to work or not.
I purchased hex adapters from Maximizer. They are composite adapters and have had good reviews. I was going to use aluminum adapters but I read reviews that said they might have some play in them.
I don't want to post to much about the motor because it isn't a Traxxas motor. I already probably said to much in another thread. If you pm me your email address I will reply with details. But yeah 38.7mph is, I think, a great top speed for an E-Maxx. I did get a speed of 39.1mph but I couldn't reproduce the results and just went with the 38.7mph. I have heard that you need to gear down because of the weight of beadlocks which will take some of my top end. I plan on doing some testing to see if the weight makes a difference.
Very nice truck dude!!! Exceptional considering that its your first build.
After seeing this truck,I'm betting the truck that you build for yourself will be one wicked ride!
Bullet/Bullet2 / Hawk2/ Blue Eagle/E-Maxx/T-Maxx
After I finish this truck I think I am going to get a 1/8 buggy, my lhs is talking about expanding and building an indoor track. Bashing is fun but I want to be able to do some racing. I'm sure I will probably try modifying it to be a more capable part-time basher.
I mounted the tires on the new rims and I love them! The rims were easy to install and for me at least easier than gluing. I also used Gorilla Tape on the inside of the tires this time instead of duct tape, it seems like it will hold better. Anyway here is a picture. I put our old body back on it and I think its going to stay that way. It is a little beat up and cracked but after looking at the two bodies I like the older one better. It is larger and gives the truck a better look.
I also tried a different thread lock, that my lhs guy gave me samples of. It has worked great so far. You just put it on the threads of the fastener and let it sit for half an hour. I'm going to start using this instead of blue loctite.
nice ole 3906. i have one all beefed up also. i kind of like the shorter wheelbase over my newer 3903 e-maxx. plus i use the bronco body. titan 775/evx-2. i went crazy on mine by installing aluminum bulkheads, skids, a aluminum chassy, and dremeling out enough space to put a summit tranny in it. it is a great e-maxx now. it isnt built for any speed. just to cruse around with my summit when nephew visits. keep up the good work, and hope to see more. peace
I'm not krazy. My mother had me tested.
Thanks. This build went a little past what I wanted to spend originally. But thanks to Ebay even after I extend the chassis I will still be a small amount under the price of a new 3908. The chassis extension should be the last upgrade for this E-Maxx, well except for the making some center shafts. It has just the right amount of speed and torque to do some good bashing. My son and I just finished doing some backflips with it in the front yard. It was funny how many people slowed down to watch us.
Aww,I liked the Dodge body,lol.
But all kidding aside, it looks real good.
And before I forget Again,your video was great,I even enjoyed the outtakes. Nice work!
Bullet/Bullet2 / Hawk2/ Blue Eagle/E-Maxx/T-Maxx
Thanks, we plan on doing more videos once the truck is running again. One of the discs that is part of the Robinson Racing slipper rounded out yesterday. The bad part is that RRP doesn't sell replacement discs so I have to buy a whole new slipper, looks like the truck will be down for a while. I might have to bust out the drill press and modify a newer E-Maxx input shaft so I can use RRP's gen 3 slipper. Or I've also been thinking of making an adapter so I can mount a newer style transmission in the 3906. The joys of RC, get one thing fixed so another thing can go wrong.
I'd have to take the tranny apart to take pictures but I used an old 3906 plastic shock body and a piece of plastic tube to lock it in 1st. Works great and I don't think the newer shaft would make a difference except being longer if the 3906 drive gears fit it.
I wouldn't think the 3985x would work in a 3906 tranny. It's a 33T and the 3906 stock gears are 31T & 36T.
If you don't like the composite hexes you might want to check these out. I'm using the Traxxas 14mm aluminum hexes that are the same style and have had no problems. http://www.ebay.com/sch/i.html?_odkw...+hex+&_sacat=0
The length is different and the part that the dog gear rides on is different. I was only using the dog gear from 3985x not the output gears. I have since gave up on the idea though. The only reason I wanted to use the newer shaft was for the extra length when using cvds. I will be going back to plastic center shafts made out of Revo wheel shafts if I extend the chassis.
There's a Baja Bug body out there for the Slash if you still want to go that route.
It's never too late to have a happy childhood.
Your signature is great and so true. All the stuff I could never get when I was a kid I buy my son.
I also figured out what I am going to do about the slipper clutch. I didn't want to have to buy a new slipper kit from RRP just for the plates so I decided to email them. They responded quickly and I am purchasing a couple sets of plates from them. I would rather have a newer slipper but they are not charging me very much for the plates.
Nice RRP is sending you some plates. I have the same slipper and haven't had a problem. Do you think the KD spring might have caused the wear?
I'm with ajcar. I like the shorter wheelbase and mines also a Narrow Maxx which I like also. There's not a lot of bodies for it but there are some. I put my Short Coarse body on it to see what it looked like and it did look like a MEAN SC .
I also like the shorter wheelbase its just the lack of variety of bodies that makes me not like it. I am going to leave it stock length for now though, I really want a 1/8 buggy. Could you post a picture of your truck with the SC body on it and info on the body?
I need to find a way to modify my 3906 chassis to take 7 cell stick batteries since I have 9 of those and no 7 cell humps.
Sent from my Transform Ultra using Tapatalk 2
E-maxx, Rally, Mini Rally
I've seen a couple of people that just strapped the 7 cell stick packs under the battery compartments. but watch out that you don't end up with the end of the packs making contact with your rear control arms or your steering servo.
Or you could just remove the end cells from a couple of packs and make your own hump packs,its not too hard to do.
When I installed my RRP slipper plate I lightly sanded the hex off the input shaft a little at a time till it fit snug. I used a emery board finger nail file and it worked great.
Hey sorry if this is a newbie question but in that pic of your original 775 titan motor set up, what are the wires with the traxxas connectors running down the left hand side for??
You also mentioned newer Emaxx steering with servo saver built in. Does that simply mean you upgraded the servo to the newer Emaxx servo? Or you have done something else?
I'm about to embark on a rebuild of my 3906 and your truck has giving me alot of ideas for mine, so thanks!!
Browsing Ebay everyday for E-Maxx items paid off today. I found a Proline baja bug body for the 3906! I had been looking for one for the shorter wheelbase but they are discontinued so I hadn't been able to find one. I can't wait till it gets here, I might attempt to paint a body for the first time.
I modified the chassis to use the steering assembly off of a newer E-Maxx. Its actually really easy to do. You can buy a kit from Traxxas but you will also need parts from the a newer E-Maxx to complete the task. I just used an steering assembly off a parts truck that I bought off Ebay. The only thing I didn't have that the kit comes was a spacer that goes between the chassis and bearing on the side that has the servo saver spring. I replaced the plastic bushings in the steering assembly with bearings. When you install the newer steering you have to cut off one of the post on your chassis that the steering assembly mounts to. I simply sanded down the cut off post until I had the correct thickness to use it as a spacer. Making the spacer actually worked out well because I was able to maintain more tension on the spring so the servo saver wasn't as weak. I hope this makes sense, I could probably take the truck apart and take pictures since I am still waiting on the plates from RRP.
Finally received my slipper plates from RRP and my Baja Bug body. While working on the truck I noticed that I bent a shock shaft. I ordered a full set of TiNi shock shafts and will replace the stock shafts with these as they bend. Also thanks to my daughter I have a set of Fast Lane Machine chassis braces on the way. I had them in my watch list on Ebay, while playing with my phone she bid $399.00 on them. I retracted the bid but had to place a bid and won, nobody else bid on them.
Im back! It seems so long since I've been on the forums. I've been working so much I forgot about RC, but now its time to do some work on the E-Maxx.
The last time I drove the truck the rear differential finally gave up the good fight. I am ordering a set of FLM hybrid diffs, hopefully they will hold up. Also I think I might get some new shocks. I never got around to changing the shafts. Now to catch up on some RC news..
Edited For Updates:
Won a pair of shocks today on eBay! I will finally have a set of Proline Powerstrokes for the E-Maxx! I've always wanted a pair and got them for under $100. I'm going to rebuild my stock shocks with the TiNi shafts for jumping so I don't bend the Powerstrokes.
I still need to order my hybrid diffs but I have found another slightly rare item that I want for the 3906. If I can't get the guy to come down on the price of the item I will order the diffs and some wheel axle cvds this weekend.
Update x2: Just purchased a set of Ultramaxxed Gen III steel gears! Now I will have an all metal geared transmission in the 3906! Also the wife said that I could still order the diffs this weekend! Can't wait to drive the truck with my son again, it's been to long!
Last edited by Zane_Grey; 08-29-2013 at 01:55 PM.
Update x3: Ordered- UE Ultralite 7.5 housings x2, Set of LST XXL axles, Hyper 7 differential x2, and bearings.
I wish I could edit a post anytime and not have to make a new post whenever I have updates. Anyway I woke up this morning and decided that I needed a set of UE knucklehead shock towers. I have bent some shocks in the past and think that the RPM shock towers may be the culprit. I also ordered some LST body posts for the towers. It really sucks that this is a holiday weekend though, my items won't ship till Tuesday!
Finally had some time to work on the E-Maxx and post some updates. The truck isn't completely done, still need to add a couple shims to the diffs and I'm waiting on bolts for the body posts. I tested the truck and don't like how the 1/8 diffs slow the truck down. I am either going to Dremel the motor plate to allow a bigger pinion, I am using 22/66 now and there isn't much room for a bigger pinion. Or I am going to try and put a newer transmission in it so I can use an even smaller spur. A big thanks goes out to EMAXXBRUSHLESS for all the help with the LST axle mod, couldn't have done it without him!!
First thing I did was instal the metal gears. Upon further inspection I don't believe they are Ultramaxxed Gen III's. More than likely Gen II's or a good copy.
Lots of parts to work with!! I didn't end up using the Powerstrokes, I just bash and don't want to ruin them. I'll probably end up selling them or keeping them with my other discontinued Proline parts. Also I didn't use the LST body posts, ended up cutting my RPM body post so they would work.
My parts from EMAXXBRUSHLESS! Such a great guy!!
I made some driveshafts, my cvds were to short again and I was tired of messing with them. I had to get the RC Monster Revo couplers machined to fit and move the position of the grub screw. Then I cut the chassis so I could use the driveshafts. I hadn't planned on cutting out so much but I messed up cutting and had to cut a lot out to make it look better. I did go back and clean up the cuts so they were straight. The wife wasn't happy about the mess I made on the table.
Still some work to do but here it is!
If you look closely you can see I even have rubber boots on the LST CVDs, thanks again EMAXXBRUSHLESS! I also removed the blue anodizing from my bulkheads and motor plate. The bulkheads were a pain to polish!!
Last edited by Zane_Grey; 09-28-2013 at 09:12 PM.
Well I got to drive the truck for a while today. I took it to an area where the city stores their gravel for road work. Everything was going great till this happened:
My drive shaft disappeared! There was a snap sound then I could hear the shaft hitting the chassis. I think one of the c-clips that hold the pin in the rear u-joint came off causing the pin to fall out of the u-joint. Then the front broke from hitting the chassis, the front u-joint was really hot! I am going to make another set of shafts and try again. I hope they work, I will need to be able to make driveshafts for my next modification.
The poor old 3906 chassis is going under the Dremel again!
Received some parts today; some 54t spur gears, body washers, and these:
I had been waiting on these to get here to start taking the 3906 apart. I was tired of using L shaped hex wrenches and decided to get a set with handles. I was going to get the AE Factory Team set but after reading bad reviews I decided on these. I have to say I am very happy with my purchase. They come in a nice case to store them in and seem very well constructed. The blue end spins so when you place the end in the palm of your hand and turn them they don't rub against your skin. I had no issue using them to take the truck apart, they even worked well on my drive shaft grub screws that I had used red Loctite on. Also the best part the set wasn't very expensive.
While the truck was apart I re-shimmed my differentials, after putting a pack through them I had some side to side play again. I'm a lot happier with the shimming this time, they feel a lot better. I still have some chassis trimming to do and I am waiting on more parts. I think the center axles are going to be the biggest obstacle when I go to rebuild the truck. I am going to try and use a cvd in the front because I lost a lot of steering when using the Revo wheel shafts as center shafts due to the large diameter. Not sure if the cvd is going to work though. I am going to try the 3906 cvd and I ordered a cvd shaft from the newer E-Maxx to try. More than likely I will end up having a set of dog bones made. In the center rear I am still not sure if the plastic shafts are going to hold up.
Impressive build Zane!! I am really liking those green beadlocks. Are you still liking them and holding up well with that brushless system? Maybe one day I can have a rig like that...well the 3903 verison anyways lol. Keep up the great work buddy!