JDV500

good evening,
i just bought a new warhead evo and it has been running great after break in. after about my 5th time of running the truck on a smooth straightaway it just quit accelerating and coasted to a stop, kept idling fine and responded to the throttle but would'nt turn the tires. i called duratrax and they were very helpful and had me run thru some test with me over the phone on the truck as i put them on the speaker. they told me something in the tranny had broken.
they said that i could take the tranny out and mail it to them for free repairs or, i could take it apart myself and locate the broken parts myself and call the parts in to be mailed to me. i took the tranny out and seperated the case halves to find the chrome cross-pin that holds the grey nylon gear to the input shaft had sheared in 3 pieces. everything else was/is in great shape. i found all the pieces of the sheared pin and cut a new pin of the same diameter and length from an old drill bit shank that i had. it fit snug in the shaft and the reccessed slot of the nylon gear with zero wobble. even discussed this with the local dealer and they all agreed, that a hardened drill bit would be harder then a stock replacement steel pin.
now upon disassembly, i've found that the gear itself has smeared smooth by the cross pin and wore away the groove for the cross pin altogether as seen in the picture here. all i can think is that the friction spring and nut on the outside were set too tight and not allowing any slippage, putting too much stress on this area inside... this is my 2nd time to tear down the truck and open the tranny in 2 days here. just looking for help with this...,
thanks in adv...joseph

davido666

Make sure the slipper pad is not to tight. I also found the three screw that attach the slipper plate to the spur gear were to long and they were digging into the one side of the blue slipper pad on mine. Also make sure your reversing servo is set correct and that no plugs are loose. You want to make sure the servo is fully ingaging the forward and reverse postions without to much pressure. Make sure all the differentials are free moving and also with no binds in them. If something is jamming sometimes and stopping the drive for a second this with break the pin real fast. I once had a servo that would twitch from vibrations because it had a bad solder joint from the three leads to the circuit board. With the radio and receiver on wiggle the wire where it goes into the reversing servo. If it is throwing the servo in reverse while you are going forward this would sheer the pin off. Hope some of these ideas might help. The only thing I have had go wrong on mine is the one way bearing and the shaft it rides on. I have hit the gas hard on mine and have not broken that pin. I did check it when I tore my tranny down to fix it. I have found that the batteries do not work well in the truck. I found the servos would not respond correct when the batteries went low. Are you using a hump pack. I would use a hump pack and you must have a fail safe. It will disable the truck when the battery gets low or it goes out of range. I found batteries would only last about 5 tanks in my truck and then they were to low.

davido666

Are the two gears for the same postion in the tranny in the picture. My gear is grey like the one on the left.

JDV500

david,
thanks for the help. will look into the areas you mentioned. i've read the manual on setting the friction spring, but how do ou have yours set.? i think now that i have had this issue twice now, i have been setting mine too tight.
i see the 3 small screws on mine here and they are short, not hitting or portruding out to rub anything, blue plate is still in great shape also.
2nd question, how tight is good when setting the gears together, from the engine to the drive gear.? should i feel a slight drag or what.??

thanks again, i appreciate the input....

JDV500

yes, the gear on the left is the new replacement gear from the store here. the right side gear is the one that 1st sheared the pin, then on day 2 it smeared itself smooth and erased the groove for the pin... that new black gear is going in now...
i'm thinking it's got to be my tension on the spring outside.
thanks,

davido666

To set the gears you should not feel a bind when you rotate the clutch bell. I set them by pushing the engine in tight to the spur gear then when you feel them binding move the motor back a slight amount. You should not feel the bind anymore. Tighten the motor screws remembering to loctite them back in or they might fall out when you start running the truck. Feel the gears again after tightening all four motor screws. Now check the alignment again by holding the spur gear firmly so it wont spin and then rock the clutch bell back and forth and you should feel the smallest of movement. You are looking for a couple of thou clearance between the teeth. Do you have the metal spur gear on the truck. It will last longer then the plastic one.

JDV500

thanks again,
just checking myself to see if what i did was correct. actually, i may have been a tad too tight there, as i could feel a very slight drag.
no, i still am running the stock nylon gear. holding up great with little or no wear markings yet. but i will get 1 of the anodized alum gears asap off of tower hobbies.
question for you, have you changed your gearing at all, or still running the stock ratios.? i've been wanting to go 1 tooth down to a 14 for low end, considering my driving area here.
can you comment on the spring tension.? the manual says 1/4 back from full tight. i thought i was there, but it seems i was still too heavy.

thanks,,,

davido666

To set the slipper pad tighten the nut for the tension spring until it goes snug, not to tight then the say to back it off a 1/4 turn but I take mine back a little further to allow a little more slipping. The slipper pad is designed to slip when there is a large amount of torque on the tranny. This helps to prevent braking of the gears. This is why some guys keep braking there trannys when they replace the motor because they want it to shoot off like a rocket but don't realize it only has plastic gears.

JDV500

got it,
good stuff there, will set it accordingly. i'll reply back tomorrow after the reassembly and testing.
football and homemade chili is happening now. have a great evening...

davido666

When you order the metal spur gear you also have to replace the clutch bell to the hardened one at the same or the metal spur gear will rip the teeth off the bell. I have metal spur, harden clutch bell, metal servo saver and metal steering arm. These are all good upgrades to get. I also recommend you fill the diffs with differential oil because they only put a spash of grease on them. My pinion gears on the front and rear had the teeth worn down because of this. The is a good web site that shows how to refill the savage diffs which are similar to the warheads. I followed it and they roll like butter now.

JDV500

good tip,

will order the gears together. should be this week and i'll get the order out. i'm looking for the site to service the diff's.

thanks,,,

davido666

Scroll down the page and you will see him rebuild the savage diffs. Almost the same inside. I used the same values of lube. You could use the same value in the front and rear,

http://ashburg.com/?cat=8

motodude11

My Feedback: (1)

hey jdv500 also get a reverse eliminator shaft had the same thing happen to me with the black gear, but the pin sheered into three pieces also[:@]!! i put the reverse eliminator shaft in it to reduce the rotational mass of the tranny and also got one of the new gray molded gears and it has been fine ever since even with the sportwerks 26 in it. Oh and btw the black gear is an older gear, its not as strong as the gray one. The gray ones are actually new molded ones and are supposes to be stronger than the black ones. Also the metal spur gear is a waste of money sure its stronger but it slows down the acceleration of your truck alot, just order 4 of the regular spur gears there only like $3-$4 at the most you can go through 4-5 of them before you reach the price of the metal spur gear and you wont have any difference in performance. just my 2 cents though, done both perfer the plastic never had one go bad either just got a bunch of extra ones laying around. Also i do agree with the steering mods that davido666 recommended just not the spur gear, oh and get aluminum clutch shoes they make a huge difference.

JDV500

thanks moto,
david, i got it all back together and test ran it, did some adjusting and tightened everything up. it's running great for the time being. i have it set a tad losser then what i did the previous time, it rev's as it gets going now instead of the ultra SHARP snap that it had when i was shearing pins. it takes off with a good lurch but not the hard snap that it had, i'm thinking i can get some mileage out of this set up now. i also adjusted the 2nd gear engagement point, it was shifting way too soon previously, like 15 feet vrs the 30 feet now.
moto,
glad to read that i just installed a weaker black gear vrs the revised grey gear. will be adding that to the list.
* where can i read up on that reverse elim shaft installation.? i see it on tower hobbies, but i want to have all the small pieces in the right places...so , for now it's running better then when i first got it...
thanks a bunch guys.

motodude11

My Feedback: (1)

dont worry about it the reverse eliminator shaft comes with the install instructions and photos not hard at all trust me.

davido666

Here is the link to Duratrax web site with the instructions.

http://manuals.hobbico.com/dtx/dtxc4547-manual.pdf

JDV500

thanks for the site david,

is there a noticable gain in performance in dropping the reverse assembly.?? i understand the weight reduction and less rotating mass. so i guess i answered my question. i want to get back into the tranny to put in a new grey colored top-shaft gear rather then the black one i just installed, especially after reading what moto said about the strength concerns. but i want to drive the current black gear in it and see how it holds up to shredding around on the property here.
looking at that metal steering arm that you mentioned now. adding it to my list to order this week.
thanks again,,,

davido666

I am still running with the reverse shaft because I just rebuilt the reverse shaft on it. I am not a speed demon I like to drive my truck on the road and on the grass. I am looking at getting the axial 28 off ebay maybe then I will convert to forward only. The motors are selling now for about 130 with shipping on ebay. I will keep driving mine until something fails in the tranny. I have put about 8 tanks thru on the rebuilt tranny with no problems.

motodude11

My Feedback: (1)

The reverse eliminator does alot for the truck as in reliability wise its just one less thing to go wrong on the truck I did it after i blew the tranny and I also put the sportwerks in it at the same time, since then have not had any problems with it plus when you remove the reverse you can also remove the reverse servo and get some dead weight out of the truck I love mine! Plus the sportwerks is a killer engine and at $125 (with shipping!!) from amain i think its the best deal around. davido666 i'd do some more research on the axial i've been reading alot of conflicting things on them. And also jdv500 when you do the aluminum drag link do the aluminum bellcrank, it takes all the slop out of the steering, and makes it a much crisper set-up. JM2C

Josh

davido666

I just came in from running 3 tanks of fuel. The super pooper ran great. It never stalled once even when the tank got low and I had to stop and refill it. It had to quit after the third because my steering servo started to mess up. I was jumping some snow banks and the servo got damp inside and decided not to work anymore. Dryed it out with a hair dryer all is fine now. With the temp outside at just above freezing the motor never went over 220 and when it did it dropped quick down to 200. After landing a jump on my rear wheels and hitting the throttle it did a wheel for a little while. I hope the weather man is wrong for us tomorrow they are predicting snow. [&o]

motodude11

My Feedback: (1)

yea dont worry about what i said guys my tranny blew again[:@], do you guys know of any after market metal tranny parts?