Monster LT1-S triple

Monster LT1-S Triple Disc Clutch for the 09-15 Cadillac CTS V

Due to an apparent installation error with the Mantic 9000 (by my local installer), I am in the position to replace that with the new Monster LT1- triple disc and compare them. The Monster LT1-S Triple is a modified GM C7 clutch to carry the third disc (see photos). As a triple disc, you need to make sure that all three discs are properly keyed to the hub - and as several of us here on the forum have found out... it's easy to miss this and not realize it until you're pumping the clutch pedal a day later.

Here is my DIY clutch replacement and transmission removal thread for those of you doing this yourself: <CLICK HERE>

Here's the clutch and "what's in the box:"
Your clutch kit SHOULD contain the following: the clutch assembly, flywheel, the slave spacer and extended bolts, new GM flywheel bolts, and a pilot bearing, as well as the plastic alignment tool. My kit was missing the extended slave cylinder bolts (necessary to accommodate the 0.200" thick spacer behind the slave cylinder) and of course there are zero instructions.

If you google, you can find two different FAQ's on Monster's website that have no helpful information specific to this clutch, aside from flywheel and pressure plate torque values. Thankfully, depending on which FAQ you see, you'll get vastly different pressure plate torque values and the torque sequence for a 6-bolt flywheel... (the LSA uses an 8 bolt).

This is not a huge deal - but it's certainly annoying and adds to the frustration when you have to repeat a step twice over due to poor literature. It's also more frustrating when you call Monster direct to verify a correct installation, send them photos - which they confirm are "perfect," and then realize that one of the discs are not keyed properly and you have to pull the transmission again! So although this scenario happened to me - and at least two other forum members here who have contacted me on this same issue - it was nonetheless ultimately my fault but I did relay this to them and suggested they update their installation instructions to point this out for all of the shadetree mechanics, that I presume would be their target audience? Monster also showed no interest in providing the missing bolts (although I already purchased suitable bolts locally, they made no gesture when I informed them of the missing parts). After three weeks, they still have not updated their website FAQ's regarding the triple disc - so IMHO Monster has come up short in the customer service department.

I ordered from Tick Performance and in addition to the Monster clutch package I also picked up a new Slave cylinder and their billet throw-out bearing support.





When installing this clutch, it is VERY easy to install it and bolt it down while having the clutch plate inside the Pressure Plate assembly become misaligned. You will HAVE to verify these teeth are keyed once bolted down otherwise the clutch will not release.


Torque the flywheel bolts in a star pattern (ie 1-5-7-3-8-4-6-2), and torque them in three passes of 15, 37 and 74 ft-lbs (these bolts come pre-coated).
Use red Loctite on the pressure plate bolts, and torque them in three passes of 20, 40, and 52 ft-lbs.


Clutch Weights:
On the same scale I previously weighed the used OEM clutch and flywheel at 65 pounds.
The new Mantic 9000 clutch and flywheel weighed in at 51 pounds.
The new Monster LT1-S comes in at 61 pounds.

These weights might vary by a pound or so either way, but seem to jive with other sources so I think it's a fair approximation. Now that I have the clutch installed, I believe the additional increase in mass (+10 lbs, or ~20% heavier than the Mantic 9000) is noticeable in improving the low-RPM responsiveness of the clutch and significant in ease of moving from a full stop, such as when at a stop light.


REVIEW:
Initial Break In (0-250 miles): The clutch engagement window is very narrow - but similar to the Mantic. I suspect this is a byproduct of most aftermarket clutches, however the smoothness of engagement is superior to the Mantic, and I believe this is specifically due to the GM disc materials and the increased mass / inertia of the Monster to help get my big, heavy Cadillac moving.

The clutch engages just and inch or two off the floor initially; this is to be expected and the pedal engagement will raise as the clutch wears in. In my case, the pedal came up to around ~halfway up of total travel after around 200 miles of driving. During similar points of the break in period (ie first few drives vs 250+ miles in); at both ends of the spectrum the Monster LT1-S is superior to the Mantic 9000 in terms of ease of modulation, smoothness and ease of starting from a complete stop. I am not saying that the Mantic is bad, as I was quite happy with it overall and it is significantly lighter - just that in terms of daily driving the Monster is a more stock-like and enjoyable feel. Really, the only negative would be the relatively narrow engagement window, although it feels slightly more forgiving than the Mantic.

At almost 300 miles on the clutch presently, it feels like it's fully broken in with a pedal engagement height half-way up from the floor and is generally very smooth and easy to drive. I have not gotten any noticeable chatter, and I feel the drivetrain vibrations are subtly less compared to the Mantic overall - but these are just my thoughts.

I will attempt to update this post as I did with the Mantic over the life of the clutch. At this point it is easy to recommend it over the Mantic for a daily driver: the Monster LT1-S Triple is a very enjoyable clutch and drives very well. So far it has performed better than I expected, more smoothly and intuitively than the Mantic and I am impressed with its manners after putting 20k+ miles on the Mantic. I hesitate to say it "drives just like stock..." but it's damn close considering the power rating. I'd say that since the Monster is also slightly cheaper, at the end of the day the only real issue is the extra mass / weight for those who are interested in the lowest ET's vs the much lighter Mantic, which drives almost as good; but I believe that extra mass is what makes it so enjoyable on the street! Pick your poison.

I'll also say that although Steve @ Monster was responsive to my emails and phone communications, overall the eagerness to go above and beyond was lacking. I feel that an aftermarket company like Monster's bread and butter are DIY guys like myself; guys who may not install clutches very often so sitting down and compiling a decent set of FYI's seems to make sense, given how much they've invested in R&D, manufacturing and advertising. After all, how many clutches get a bad reputation because of possible installation errors??? It would be in Steve's best interest to do this I would think, and it would have saved a few of us here on the forum an additional week of trouble shooting and pulling the transmission a few extra times! I like the clutch so much, I wish Monster as a company would perform better in terms of product support, appropriate documentation and making gestures of customer service that help foster a relationship with the end-user, as Mantic did. I had a much more enjoyable relationship with Geoff @ Mantic USA, who was quick to get needed parts to me in a timely fashion - but to note the scenarios were also different and that doesn't detract from my opinion that the LT1-S is the better clutch so far.

Stay tuned!

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Here are all the "while you're there" parts I've compiled for the clutch swap. Not all are required, some will come with the clutch kit you buy, but either way please verify your part numbers before ordering... just in case!

* Bronze shifter bushing - $19 from www.thegearbox.org
* TR6060 input shaft / Front seal (#89059435) - $4 from www.thegearbox.org
* TR6060 output shaft / rear seal (#89059483 / TUSJ2042) - $12 from www.thegearbox.org
* LS Rear Main Seal (#89060436) - $18 online

* Pilot bearing (usually included with clutch, #12557583) - $11 online
* Slave cylinder (usually included with clutch, #24281248) - $200 online
* Monster billet Slave / release bearing support (replaces plastic OEM) - $80 from Monster or Tickperformance.com
* Hydraulic Clutch Main (Master) Cylinder (#24238683) - $108 online
* ARP 234-2801 flywheel bolts (replaces more expensive GM# 12563485, which are 11mm x 1.5 x 29mm long)