98Bluebirdls1

Im getting my 4l60e rebuilt and im still debating if a shift kit is worth it because i can actually shift the car either way and have torque management deleted. can someone explain how a shift kit benefits the 4l60e? js again my mods are heads cam and intake and im running corvette servos unless theres other servos that are better out there

99 Black Bird T/A

iTrader: (4)

There are a lot of bad to mediocre shift kits on the market. It's best in my experience to work with a very knowledgeable transmission shop or tuner to explain exactly what you are looking for and expecting.

The former owner of my girlfriend's son's Z28 put a B&M shift kit in the car and it's horrible for a daily driver. It kicks like a mule 1st to 2nd gear.

A friend has a Transgo kit in his TA and it's better than the B&M in my opinion in all regards.

When my 72 vette got the TH400 transmission rebuilt in 2009, I picked up the internet recommend Transgo shift kit. The shop took one look at the box and said no way are we using that kit. We've been doing this for 35 years and have our own kit that's better in every way. I asked about the B&M kit. Trust us on this you don't want either one of them but the Trans go sucks less than the B&M sucks. They were dead on the money. The TH-400 is crisp shifting without been annoying. The transmission shop had an excellent reputation locally and delivered.

Back in 2008 I went through the same discussion about the 4L60e with the shop whenI was getting the 4L60 rebuilt.

This is my experience with shift kits. Both of the custom kits the shop did I like.
None of the off the shelf B&M or Transco kits I've experienced driving or as a passenger were as ideal as the custom kit from the transmission shop.

youngengines

A firm shift will help the clutches last longer.. a very smooth shift comes from slippage, which hurts life.

coryforsenate

iTrader: (1)

I put the Sonnax Performance Pack in mine during the rebuild. I'm a fan, the shifts are a little firmer than stock (you'll only really notice the 1-2 shift) but nothing harsh or unpleasant.

The Transgo shift kit is really popular too. I don't think you can go wrong with either one.

As youngengines mentioned, firmer shifts will lengthen the clutch life span.

RevGTO

iTrader: (12)

With a stock converter, I might not install a shift kit. I think you could get most of what you want through tuning.

With a smaller aftermarket converter, a shift kit is a must for me. First of all, the tranny's coming out of the car in any case. Firm up the mushy shifts, get better oiling throughout the unit, and eliminate PWM which could compromise clutch life. Plus various valves, springs, and odds and ends that make for better performance and longevity.

Docrocket1967

iTrader: (1)

The Transgo kits are great in my opinion

DANOZ28

iTrader: (1)

i never added a shift kit because i was worried it would bark the tires every shift while normal driving. somebody told me there were like 5 different levels of shifting you could choose from is that correct for the trans go kit?

bbond105

Yes you can adjust the shift feel to your likening.

DANOZ28

iTrader: (1)

im sure this has been asked before but is there any performance gain at the track with a shift kit?

Docrocket1967

iTrader: (1)

Absolutely

mrvedit

Concerning the Transgo HD2 kit, all the pros here recommend not installing any of the supplied washers into the 1-2 accumulator, or at most one, certainly not two or three.
Making the 1-2 shift too firm not only is unpleasant to the driver, but it can break internal parts, u-joints, etc. For this reason the B&M shift kit should never be used, and if already installed, should be removed.

Even if a full shift kit is not installed, I recommend installing at least a bigger boost valve such as the .490" Sonnax 4l60E-LB1 (or LB2 for ISS units). As mentioned, a shift kit helps a trans life longer under performance conditions by reducing slippage (and wear) during shifts. Also, the complicated 3/4 clutch circuit over time tends to start leaking a bit in any number of places, and drilling the separator plate's 3/4 feed hole bigger helps provide enough volume to overcome small leaks.
These are just a few reasons why a shift kit is worthwhile.

mOtOrHeAd MiKe

iTrader: (8)

There was a full stack of shims used in my RPM Level 5 4L70E when they installed the TransGo HD2... looked like a stack of casino chips.

The kicker is that you can crank up the programmed pressures and shift speeds in the tune and that will only net you what the stock components are capable of delivering. Alternatively by reprograming the mechanical aspects of the transmission you can overcome some of these limitations - basically making the transmission more analogue in the process - with a "shift kit"; plus you can make it function differently with specialized parts (like the HD 2-3 shift valve from Sonnax).

At the end of the day you should do both a shift kit (or kits + other components) and tune the transmission to get the performance you desire/require. Tuning it properly will require datalogging the commanded vs. actual pressures using a pressure transducer, and the calculated vs. delivered torque - it really is a multifaceted approach. At the end of the day all of this PWM stuff was added for comfort and reliability (in the sense that the TCM could compensate for irregular or changing conditions (such as temperature or load)).

joecar

Line pressure is controlled in 2 steps: PCS solenoid regulates Torque Signal pressure which pushes on the Boost Valve which regulates line pressure...

tuning takes care of the first, mechanical means takes care of the second.