Dutch SS

iTrader: (3)

I know that Yank, FLP, and the Speed inc trannies are all Vacuum Modulated, and they seem to work well. Has anyone converted a stock tranny or a regular rebuild(not performance) to Vacuum Modulation, and how did it work out? How hard is it to do, does the trans have to be out of the car? Anyone have any info on this they could give me, i would really appreciate it!!! Thanx in advance

GreekZ

After some research I found out you can't install
a vacuum modulator on 4l60/700r4 trannies. They
only work on 4l60E transmissions and you can purchase just the kit from Speed Inc. I think it's
around $100

Jorday

Good piece of information, I didn't know there was a kit available to convert to vacuum you could use on a stock transmission

WILWAXU

iTrader: (6)

ahh Greek, all LS1's have a 4L60E

The vacuum modulator is the way to go, get the computer out of the line pressure business

Jorday

Screwed up line pressure is how my stock trans got messed up.

BLK02WS6

iTrader: (2)

I just called Speed Inc. to order one - they don't sell it in a kit, only in their trans.

Anyone know where else to get a kit to do this? I really want to do this!

Jorday

Maybe there isn't a way to just convert the stock trans easily?

BLK02WS6

iTrader: (2)

I am about to buy a performance rebuild locally and the guy hasn't started converting to vacuum modulation yet. I think I am either gonna wait till he does (if mine will hold out) or get it somewhere else.

I think that once we start modding our cars, we cause the computer to wack up our line pressure. Ever since I put in my new motor, the shifts are terrible. Trying to increase the line pressure with Edit seems to be hit or miss. Maybe it is all the newfound power, but I don't think so because it was instantly worse.

I wanna convert one way or another! I have heard more than once that this is the way to go.

Anyone know what if anything you have to do to the computer when you go to vacuum modulation?

Z-Rated

sorry for my ignorance, but what’s vacuum modulated? is that where its not electronically controlled but contorolled with a vacuum likt the T400s? and what’s the difference between the 4L60 and the 4L60E? ones electronic and the other one isnt?

BLK02WS6

iTrader: (2)

I am pretty sure you are right about both.

The way I understand it, vacuum modulated means the trans line pressure is controlled based on engine load as determined by vacuum - instead of the computer determinging what the load is.

And from what I understand the advantage is that some of our mods and tuning can throw the computer off and it does not provide the proper line pressure - sloppy shifts and burnt up trannies result!

Anyone what to jump in and clarify that?

And yes, the E is the electronic 4L60.

Jorday

You are correct. The line pressure can also be too high. That's what damaged my stock transmission. Now I have the Pro Yank 4L60E with the vacuum control line pressure. The shift kits for stock transmissions increase the line pressure with a new pressure valve to try and make the shifts harder. It is not a good idea to mess with the line pressure in LS1 edit and install the shift kit. The line pressures are so high you can run into problems. First of all, when my stock trans was like this, my trans cooler lines would not stop leaking no matter what I did. I had two clamps at every joint with barbed fittings and it would not quit leaking. Then my pump went out from my line pressure being too high. It got nuked.

You can also get too low of a line pressure with the computer controlled line pressure, which will can cause the band and clutches to slip on shifts at WOT. This can be caused by the ported MAF mod in an A4. The engine will see less load because of this mod letting more air in than the PCM thinks, which will help to increase your spark advance. Problem is when the PCM senses less load, it will reduce the line pressure and and the clutches can burn on shifts.

Z-Rated

Cool, im not as dumb as I tought
Has any one done this to thier tranny? Id like some details because I am planning for my converter

BLK02WS6

iTrader: (2)

As they said up above, some performance trannies come that way.

And I'm looking for a conversion if one exists, or I'll go with one already built that way.

Z-Rated

I meant a conversion for there tranny. I know that they already have one built that way.

Dutch SS

iTrader: (3)

Thanx for all the replys........ so far, the only company that i can find that offers the conversion (without buying a new trans) is: http://www.pro-built.net/index.cfm?f...;productid=179

It is not expensive, the only problem is I have no clue how to install it, and am very wary of someone else installing it who is not familiar with it. My luck , they would install it wrong and void my tranny warrantee. If anyone else has any additional info, PLEASE keep posting up!!!!!!

Thanks again......

RPM WS6

iTrader: (3)

The Vacuum kits used for Speed Inc trannies are from TransGo.

I am 95% sure that the FLP units also use the kit from TransGo, I will find out for sure in about 2 weeks when I get my new FLP Level IV installed.

TwoFast4Lv

iTrader: (8)

LOL

For the LS1 guys yes this can help with screwed up tuning and lack of tuning.

I can get them all day long. I have one for a 4L80E sitting on my bench as I type.

It is a very nice crutch...but nothing more. It will help get you through TQ management.

Later

Ellis

WILWAXU

iTrader: (6)

From what I've seen, I would not buy a aftermarket tranny without a Vacuum Modulator.

BLK02WS6

iTrader: (2)

If it is a crutch, wanna let us in on the secret - what is the better way?

I don't have torque management anymore (deleted with Edit)
- don't most people get rid of that right away? I don't understand what you're getting at there.

My tuning is very good, so maybe in my case it is just a matter of a stock tranny going south after some abuse and too much HP.

I agree with Wax - from everything I've heard, I wouldn't buy a performance tranny without vacuum modulation. If there is some better way to go, I'd love to hear what it is.

BLK02WS6

iTrader: (2)

Thank you! This is what I was looking for.

I'm gonna talk to the local performance rebuild place about this. He has been wanting to start providing his performance trannys with this - I'll volunteer to be his first.

I'm sure a professional rebuilder would know how to install it. And it appears that it comes with the solution to make the PCM happy too! I'm gonna call Pro-built as well and talk to them. I'll bet that it is not hard to install and I'm sure they provide instructions. I'm gonna do the Transgo shift kit that they recommend as well.