Unlimited Engineering, Inc
500 Dunwoody Drive
Simpsonville, SC 29681


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SKU: 13540

Catagory: Differential Manufacturer: UE

Description: SuperMaxx UltraLite 7.5 Differential Kit, 6 Spyder
Fits : Traxxas T&E-Maxx


7.5 Differential Gear set for the Maxx (1/8th scale gears) 6 gear spyder setup

As some of you know Iíve been developing a much stronger differential for the Maxxs for some time now. Tremendous research and development went into the selection of the gears and the design of the differential. Countless hours of testing have revealed that this is a nearly bombproof solution the High Powered Maxxís differential needs.
Weíve selected the 7.5 gears as the standard. There is a wide variety of differential styles available from open 6 spyder design to torque sensing differentials.

The first offering Iíll be making to the Maxx community will be a differential that fits inside the standard Maxx bulkhead.
7.5 Differential Kit includes:

SuperMaxx UltraLite 7.5 Gear Case (~35 grams)
● Differential Gear Set, 7.5, 6 Spyder 13542
Helical cut Ring and Pinion Gears
Diff Cup and pins.
● Huge 8mm x 16mm Rubber Shield Bearings

  (these are the really good ones)
SM hardened pinion drive cup
SM hardened Output Drive Cups & Shafts

● Shim kit

● Detailed set-up instructions

and everything else you need to set up a complete truck



Kit is made from top quality 7075-T6 aircraft aluminum.

Finish is natural and Polished to a high luster

Installation requires grease

  (diff loc lube if desired) and blue loctite

Helicoils in the mounting holes - these are

   hardened steel threads which will never strip

● Allows proper Ring gear orientation for

  both T & E Maxx 

These can be used in the T or E Maxx.

E-Maxx has the ring gear installed on the opposite side as the T does. You must either put the ring gear on the correct side or run your motors/transmission backwards (which is a major No-No.)

We've even gone so far as to mark the inside of the case so you know which side to put the ring gear on.
 The outputs are compatible with UE and MIP CVs. The Dynamite & XTM CVs drive cup is 3.5mm longer - which probably means that the shafts are 3.5mm shorter and will be too short. Stock Plastic sliders will not work. XTM center shafts will not fit the pinion. A Center Shaft kit for the XTM chassis is now available.
 The gears offered in these bundles are Ofna's 4 spyder 7.5 gear design. They have held up quite well, are readily available and have yet to break (even when I made an effort to destroy them.) Ofna has made a special kit just for us - The SuperMaxx 7.5 Gear Set.
 I will offer the Torsen's but will warn you that these should not be used in high horsepower, no slipper (or very tight one) applications. We are working closely with Ofna to improve their Torsen's strength. They were doing fine in SM BL-E until I made a serious effort to break them, then they did fail Ė some of you have seen the pics. At this time I'm going to recommend sticking with the 6 spyder gear design and if you want more bias use the heavier silicone oils. These should fit all the 7.5 diffs on the market, though with the variety of them Iíve yet to verify this. We may have to make drive cups and or output shafts for them. If you have one that you wonder if it will fit, send it to me and Iíll check it out for you.
Lubricants are not included. Due to so many different selections and options (for traction control) on silicone oil for inside the carrier (where the spyders are)  we've elected not to include them. At $10 a bottle it would drive the price up pretty quickly. For the Ring and Pinion use a premium quality grease (I get mine from the local auto parts store.)


 These do lower your overall gear ratio, you will need to gear your truck up.
 Maxx R&P ratio is 2.85:1
 7.5 R&P ratio is 3.31:1

For this reason you must upgrade both ends of the truck at the same time. Do not try to mix ratios.

 If running 22/72 with the Maxx ring and pinion, 23/65 would  be the identical ratio with the 7.5s
 Iím running 22/66 at the moment. It has tons of bottom end, but feels like it could use some more top. Though there is no question the truck is fast even on a large track. (I had a 23 but it had a problem and Iíve not gotten it replaced yet.)
 Perhaps Strobe will come up with some more options when he releases his 1.0 module gears/slipper/.21 clutch (Maxx is 32 pitch.) There are far more clutch bell/pinion options available for the .21s

We will also offer an adapter kit which will allow those of you with stock gears to run them in the UltraLite case. This for those of you who want a stronger housing, but are not ready to take the plunge all the way into new gear sets.
Hope you all like these.

These are high precision gears, setup is critical for long life and smooth operation (same as in full sized cars and trucks.) While the instructions are very detailed on how to do this, it's not quite as easy as put screw A in hole B. Patience and following the instructions will ensure success.

List Price: $325.00 Sale Price: $292.50
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