How To: Tmaxx Diff Shim Mod

[NitroRCracer]

mods please note: due to limitations per post, i had to split this "how to" over a few posts.."

Tmaxx Diff Shim Mod.

This page will describe how to shim your Tmaxx diff, to remove excess play and help your diffs last longer. It also enhances the posi effect and keeps dirt out your diff, and the greases in.

You will need the following products.

Yokomo Diff grease/ Lock lube - CS-DGH (hard) for rear, CS-DGM (medium) for front.

I noticed its now obsolete on tower but you can get the same type of grease from a 1:1 car suspension specialist in a larger tub. i beleive its the same stuff used to install eurathane/nolathane bushings..
it should look & feel like a very thick, sticky, waxy "vasoline" and is a silicone based product. (no, DONT use vasoline instead!)

Automotive grease like Valvoline etc (good quality grease)
6mm Steel shim & 10mm Steel Shim. (approx 10 of each)
6mm Teflon washers
5mm x8mm O-rings
Traxxas Foam body washers # 4915





(inside and outside refers to the side of the truck in the turn)

In the turn the outside has good traction, and the inside doesn't. The inside will "diff out" (spin ALOT faster than the other side) if you're pushin' it hard. When the inside hooks back up out of the turn, it will shock load the driveline if the track is sticky.

Packing your diff cups w/ grease will lessen the diffin' out and it will put more power to the ground. The diff action will still be there, unlike a spool, so you won't have turning issues. If you decide to try this it's easy to do and totally reversible if you don't like the way the truck handles afterward. I like the way it handles, you can throw it in a turn, steer the wheels back out, and steer it on the throttle. Kinda like sprint cars on dirt

The medium lube in the front doesn't hurt turn in.

[NitroRCracer]

-Remove and clean out diff cup

Pic 1 + 2 -Dry assemble spiders in cup and trial & error 6mm shims to remove excess endplay (should take 3-5 shims). You don't want it tight, so leave a little play (.010"-.020").

Pic 3 - Keep the stock plastic washer against the cup. Split the shims side to side (equal # on each shaft).

Pic 4 thru 10 -Apply lock lube to cup side gear and install into cup w/ shims. fill cup approx. 1/2 w/ lube and install spider/shaft assy. Fill rest of cup, leave a depression slightly smaller than ring gear side gear (try to leave no air). Apply lube to other side gear and install into ring gear w/ the rest of the shims. Assemble the ring gear to the cup (some grease will squirt out).

-If you want to improve ring gear/pinion mesh, now is the time.

Pic 11 thru 14 -Dry assemble the cup assy. (carrier) into the case w/o the pinion. T & E the endplay w/ 10 mm shims (they go between the brng and the carrier) to .010" - .020". Keep track of # of shims (we'll call this the preload shim pack).

Pic 15 & 16 -Install pinion and adjust shims on ring gear side to move the mesh tighter. Put the rest of the preload shims on the other side and dry assemble the case to check. Some tight spots are fine, but you should be able to turn the pinion shaft w/ your fingers. Play w/ it till you get it right, might take a few tries.

Pic 17 & 18 -Disassemble and grease ring and pinion.
-Final assemble diff

-Pic 19 I also use the foam body washers on the yoke to dust seal the brngs. Clean the yoke and stick it on. You will have to stretch it slightly to go over the raised area in the center. Apply some grease to the exposed areas of the foam before assembly. The foam will be tight at first, it will loosen up in a run or two.

Pic 20 -Use the o-ring between yoke and diff on the shaft during assembly. This will seal the diff and enhance the posi effect (w/out the o-ring you will get a blob of lock lube in your yoke). You will have to push HARD on the yokes to get the pins in.

[NitroRCracer]

[NitroRCracer]

I hope this was as helpfull to you, as it was for me..

[Tommy Gunn]

Have you ever tried something in the 50000 diff oil? I'm going to try this mod. I took the stock grease (which was next to nothing) out of my boys buggy and put in some good OFNA Diff Oil and it made a ton of difference. It stopped it from unloading and spinning the right side tires all of the time. She hooks up and goes now. If it helps anywhere close to as much as it did the buggy this will be a big plus.

Tks for the post bro.... Let me know what you think on the 50000 diff oil.

[NitroRCracer]

i use the yoko diff greases because they dont melt like other greases, and they arent messy to clean up after (regular grease flicks everywhere)

i havent tried the 50k oils tho. is it like a honey type of oil (thick liquid) or is it actually a grease?

[Tommy Gunn]

It's a very thick oil... thicker than honey probably. I had someone tell me that the 50000 oil would hold up in a transmission on a tmaxx for a weekend of racing without the mod to seal up the diff. case. It's so thick you can't squeeze it out of a nozzled bottle you have to take the lid off.



Here is the OFNA Oils.
I didn't realize but it goes up to 120000

http://www.ofna.com/acc-fluids.html

[NitroRCracer]

if you do use something like that, only use it within the diff cup/spider gear area.. using it within the main diff housings will cause huge drag on your driveline and probably an overheated engine which isnt what we want (you probably know that tho)

edit: hmm, they look alrite.. i mite have to give them a go next time i pull it apart.. thanks for the link mate

[Davcruz]

Very nice write up and excellent pictures. Maybe you put this in there somewhere and I missed it, but where did you get the shims?

[NitroRCracer]

the required items list at the top of the page has clickable links to the items i used on tower hobbies.

you can also get the shims from collandra racing with the link below.
http://www.teamcrc.com/crc/modules.p...category_id=79

the pictures and "how to" was given to me by crower28, i added the number references on the pics + write up, and kinda tied the whole lot together.

thanks for the mod crower, it works excellent!!

[cands]

nice write up!

teamcrc (Calandra Racing Concepts) are about 20 minutes away from me. Mark, Frank Jr., Frank Sr., Jeff are all great people and will help till theres no end. They are my local hobby shop also.

[Davcruz]

Originally posted by NitroRCracer
the required items list at the top of the page has clickable links to the items i used on tower hobbies.

you can also get the shims from collandra racing with the link below.
http://www.teamcrc.com/crc/modules.p...category_id=79

the pictures and "how to" was given to me by crower28, i added the number references on the pics + write up, and kinda tied the whole lot together.

thanks for the mod crower, it works excellent!!

Ahh, so they are, I knew I probably scanned it too quick.

Thanks for the excellent post, I need to do this to my diffs and your timing was just about perfect!!

[civicxmax]

dang i did this and it worked so good

[K.B.808]

so the spyders and other guts come from the old diff right? just swaping out the cup,pinion and diff case right?

[MadMaxx_Rb.23]

nice write up!!
note that this will work for most but if your spider gears are worn you should replace them as this mod will not help you!!

[SmokinAces]

Any idea on where these aluminum diff cases are from? The only cases I can readily find split form front to rear, not side to side into halves. I would think the cases shown here would be better for shimming/fitment IMO.

[Dec1973]

Any idea on where these aluminum diff cases are from? The only cases I can readily find split form front to rear, not side to side into halves. I would think the cases shown here would be better for shimming/fitment IMO.

Heres one mate.
http://cgi.ebay.co.uk/4PC-TMAXX-T-MA...QQcmdZViewItem

It would be better if you could get the Maximizer aluminum cup. As problem always start from the cups.

[Nitronaught]

This is the best write up on shimming diffs I have seen!!! I use it myself.
I did take the plunge and got the UE kit for stock gears. Comes with Kippster cup, 7075 T6 cases, 3 MM screws, oversized sealed bearings and shim kit. If yu want to you can later upgrade to spyders and use the same diff cases.. They do cost though, $72.00 each and you need 2 of them if you do both diffs.
I can say I have quite a few gallons through them, they hold up great!

[SmokinAces]

Thanks Dec1973!

I bought 'em as soon as I saw them! Exactly what I was looking for. I appreciate the lookout there!

[SmokinAces]

So yeah. I wasn't paying attention. Silly me. I needed cases for the Revo and of course this shim guide was outlined for the T-maxx truck. So my question now is:
Will T-maxx diff cases fit in the Revo?

[TRXnewbie21]

probably not since revo diffs won't fit in a maxx.

[NJT-MAXX]

I ordered this stuff from Tower. I am using Nitros suggestion and will use bearing grease. I can tell you this, as of Monday, the 10mm shims were on back order.

[Nitronaught]

So yeah. I wasn't paying attention. Silly me. I needed cases for the Revo and of course this shim guide was outlined for the T-maxx truck. So my question now is:
Will T-maxx diff cases fit in the Revo?

Revo diffs are sealed, You would end up going backwards in technology. You can still shim your Revo diffs though. If they need it.

[thundermanmike]

Since Yokomo no longer makes their lube, what does everyone suggest we use? I'm looking at the Ofna Differential Lock lube. Has anyone tried it or has another suggestion?

[NitroRCracer]

i have been using the associated 100k + 300k lubes, the 100k works real well.

its much better value for money than the real small yokomo tubs aswell because you get about 4x more product.

[thundermanmike]

Thanks Nitro. Great post

[trulyrcnuts]

great post will have to put this in the to do list

[Flying Monkey]

just checked my tracking number and all my parts are in so ill be doing this tonight to my new diffs

[theartist]

Great write up!
Just ordered the parts to do it.

[Flying Monkey]

yeah i did mine per this and lubed with lucas x-tra grease. seems to be working good. IM about to do it to another set of diffs for my project 2.5 maxx for my step son. took my time on the first diff as ive never had them open before but the 2nd diff went fast.

[Tuskony]

Hey all the pictures are x'd for me....

[Overkill]

You can find this article HERE Tuskony.

[Tuskony]

Thanks......

[NitroRCracer]

try a refresh

[Tuskony]

They work now.

[jpoprock]

Great thread. Thank you!

I am getting ready to do this today... but I'm a little confused on what kind of grease to use. You guys refer to the grease in thousandths... like 50,000, but I don't know what that means. I bought a used RC moto, and the seller sent me two bottle of diff grease, and it is clear silicone. One bottle says 1000 and the other bottle says 3000. Will either of these work?

I also went to the auto parts store to look for something to use, and nothing they had showed any reference to anything "50000". It's all weight measured. So, what can I buy that will work?

My neighbor gave me some white engine grease for a car, and he seemed to think it would work great, but I don't know.

I want to finish this today so I can get my truck running, and if what I have doesn't work, then I need to know what I can buy at an automotive store that will.

Thanks!
Jason

[Systemlord]

Excellent differential shimming guide! The best grease money can buy is Gorilla Snawt, its designed for high RPM differential's gears and any moving parts. These nitro monster trucks run much higher RPM's than any real life size cars or trucks.

http://cgi.ebay.com/GORILLA-SNAWT-RC...QQcmdZViewItem

[NitroRCracer]

posted in 2005 and this thread is still kickin' on.

woot!

Jpoprock

the weight depends on what sort of effect you are after.
the 1000 + 3000 you have are buggy diff oils and will give a very light effect. probably too light to be of much benefit, imho.

http://www3.towerhobbies.com/cgi-bin...93p?&C=CMH&P=7

the associated greases in the little clear tub is what i use nowadays.
i have the 100k and a 300k and sometimes mix a little of both for a 200k front.

if i open and "up end" the 100k it moves very slowly in the tub. you could probably make a coffee before it leaked

the heavy Mugen lubes on about page 3 of that link should work well too

[Nitroxda]

This thread qualifies as a super sticky..!

[egoneski]

Will this work for an emaxx 3905?