Volume III, Issue 1, Page 11

There are millions of these transmissions in the universe (with favorable 3.06, 1.68, 1.00, 0.70:1 ratios), but most of them in need of better internal gizmos—even when new.  Remember that new car manufacturers surely anticipate that you will be buying parts in the not-too-distant future, so just about everything is planned for failure. When you apply a massive increase in torque, the inevitable creeps that much closer to your door.
So it makes good economic sense to incorporate a stronger, more viable link between engine and the rear axle along with the proper torque converter to liven things up. For this, we whistled twenty minutes up the pike to Monster Transmission & Performance (Spring Hill, FL).

The conference clustered around several salient issues. We didn’t want a high stall speed converter that would take lots of throttle to get the vehicle moving. We didn’t want part-throttle shifts that would constantly test the link between spine and skull. We didn’t want the tires to chirp simply by dropping the lever in Drive. We didn’t want to put drag slicks on it. We did want a smooth-shifting transmission composed of premium parts capable of withstanding 500lb-ft with composure. We did want the full Monte when we flattened the throttle to the floor. Barking back tires is just fine with us.

Monster listened. Monster interpreted. Monster gave us exactly what we wanted. 

The original transmission felt strong enough but didn’t shift up (especially on the 1-2 exchange) to our liking. Despite the reprogrammed quality via a Crane Powermax hand-held programmer, the transmission would always hesitate a tick or two before completing the shift. Though annoying, it more or less signaled that the transmission was beginning to slip, but this wasn’t really obvious until the day we’d driven Monster’s rendition.

Whereas the stock torque converter has a stall speed of 1,650rpm, the Monster performance converter pushes the limit to 2,300rpm, and unless you make a point of it, it behaves exactly like the OE unit. No heavy lurch against the motor when you pull the shift lever from Park to Drive. At 800rpm, it’s tight enough to crawl through a traffic light. When you mash the loud pedal, the thing hooks up and leaves without hesitation. Keep the pedal planted and the tires squawk a hearty approval on the 1-2 shift. Part-throttle up-shifts are firm and immediate but never obnoxious, never embarrassing, never a jolt that you didn’t expect. Build on the brake a little and the back tires spin with ease. Is this a good thing? We don’t know…but we like it. On the road, the revitalized tranny feels like it means it. Everything happens quicker and snappier, giving the vehicle that “of-a-piece” crispness.

This lesson is to familiarize you with the things that Monster changed in the 4L65E rather than a step-by-step rebuild, which has been the subject of countless tech journals. We have neither space nor desire to recount it here. The Mega Monster lists for $1,495 which includes free shipping and there is no core fee. If you want something that will deal with 500lb-ft day in and day out, that figure is pretty much in line. While some aftermarket tranny builders test their stuff on a type of dynamometer, Monster takes it a long step further. It runs in the real world. That ratty, road-rashed Monte SS with the scabby wheels, AKA the perfect street race sleeper, has a 500hp 383 and is the test bed for every GM transmission that Monster squeezes.

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