I have a 79z28, how difficult would this conversion be. And will it work with my current shifter, B&M Quicksilver.
I know there is 2 versions of this tranny, the 4L80 and the 4L80E. I am thinking the 4L80. I don't want to have to have a separate computer just for the tranny.
2. will this tranny stand up to a bigblock 450+ hp.

Any thoughts,
Chris :brightide

I have a 79z28, how difficult would this conversion be. And will it work with my current shifter, B&M Quicksilver.
I know there is 2 versions of this tranny, the 4L80 and the 4L80E. I am thinking the 4L80. I don't want to have to have a separate computer just for the tranny.
2. will this tranny stand up to a bigblock 450+ hp.

Any thoughts,
Chris :brightide


conversion is fairly simple, but a new crossmember will be needed most likely as it's much further back.

I've heard people call them a 4L80 but as far as I know they're all the 4L80E (electronic) and require a control box of some sort to run. There is someone modding one to not use the box, but it would be cheaper to get the control box I believe.

Jody

402Z28, I'm gearing up for this swap myself. I ordered a 4L80E (like cam said, I'm pretty sure that's the only designation as they all came electronically controlled from the factory IIRC) from Jakeshoe with a full-manual valve body. I went without the computer for cost reasons, but if you can afford it, it is a much better option. Without the computer you basically have a TH400 with overdrive and a lock-up TC. It came on diesels and big blocks from the factory, I believe so it will definitely live a healthy life behind your big block. If you get the full-manual version, it's just that. There's no TV cable like the 700R4 or kickdown cable. Any 4-sp auto shifter will work (including your quicksilver). You will need to switch to an electronic speedo, get an electronic-to-mechanical speedo conversion, or a mechanical speedo tailhousing. You will also need a lock-up kit if you get a lockup converter and don't already have a means to control it. You need to have a flexplate with a compatible bolt pattern and a TH400 slip-yoke. Also, you will need to cut down the stock driveshaft or have one custom one made. The only other thing I can think of (and I haven't figured it out yet) is a tranny crossmember. I will most likely be fabricating my own, but it's possible that you might be able to use a TH400 crossmember and relocate it rear-ward a few inches (somebody check me on that). That's all I have for now until I get this project underway.

interesting, Brian.. I thought you were doing the manual VB just b/c you wanted to shift manually.. I was asking myself, "why didnt he just do a TKO?"..lol I didnt know you could do that & bypass the computer control.. That's pretty cool.. Makes the swap alot more affordable, as long as you dont mind having to do your own shifting.. Guess if you dont mind having a manual, you wouldnt mind this..And you dont have to worry about missing the gate, b/c you are shifting in a straight line..Cool..

I will definitly look into this for a future upgrade, once I blow up my 700r4 b/c I'm sure I will sooner or later..

Jody is correct,
all 4L80E's started life as electronic versions.

The computer itself is about $400 more than the manual conversion, plus when retaining the electronic control, you would replace the shift solenoids and other internal sensors that add to the cost.

The manual conversion uses a vacuum controlled modulator valve to control line pressure. This can also be used on the electronic versions to eliminate electronic control of line pressure. It seems to help on the 4L60-Es for the LS1 guys.

I'll let you know how it turns out, Joe. Jakeshoe has an awesome reputation for his tranny work and he told me that the 4L80E's street manners won't be bad at all with the full-manual. The full manual deal is nice for install too since there are no annoying cables *cough* TV *cough* to have to calibrate. You just shift when you're good and ready:). Also, part of the plan from the beginning was to get a Gear Vendors unit with the 4L80E for double overdrive. That means eight manually shifted gears with the double OD gear ratio being only 0.09 deeper than the T-56 6th gear and no clutch!

Ok I just read Jakeshoe's post. Jake, can you give me a little more info on the vaccuum modulator? Does it get input on how hard to shift from some other source (TPS or kick-down type cable)?

No,
No cables or sensors, just a vacuum line to the transmission like a TH350 or 400.
Simple reliable operation.
This is what allows you to have reasonable line pressure and shifts that will get progressively more firm with throttle.

That is another point with the electronically controlled 4L80E, you must have an input from the distributor (RPM) and a throttle position sensor.
If you are already running an EFI system, this stuff is easy, however on a carbed application you have to do some fabrication or buy the $200 TPS setup that hooks up like a TV cable (cheesy IMO).

Well wouldn't you know it, I am running an EFI system (Stealth Ram). Still sticking to my full-manual plan though. I would like to use the computer (off a late third gen) to automatically lock up the converter. Jake, while I have your attention, is there a crossmember that works on 2nd gens for this swap? Thanks.

Brian, have you chosen a shifter yet to handle this type of constant duty?

I was toying with the Retrotek pushbutton and paddle shifter combo but I don't hear enough good things about it to risk using it constantly, not to mention spend that kind of money. I think the only shifter I feel comfortable with would be the Hurst Quarterstick. Not as pretty as the Quicksilver or Promatic but damn near indestructible, which is what I'm after. Plus I can get a console mount cover plate from the 3 spd version to install it in the console a little more cleanly.

I always build my own crossmembers but you might check with BTO.

I think any quality shifter would handle the constant duty if you lube it well on install and occasionally regrease it.

according to BTO's site, they have a 4L60E crossmember, but no pic or price..
weird b/c they dont list a 4L60E tranny, but they do carry the 4L80E.. :confused:

I'll do a little research on the crossmember and see what I can come up with. i may be able to build them if I can get a car to mock one up.

I have already installed a 4l80E in my 71 Firebird, and I love it. You are correct that a new crossmember is required, I built my own out of square tubing (I wouldn't use square again, I would probably do it with round tubing next time).

One thing I would like to mention is that the best thing about the 4l80E is the electronics part. You can do a huge amount of transmission tuning quickly and easily with a cheap laptop. I have mine set up so that if I am driving slow (Grandma in the car for instance) it shifts smoothly and quietly, but when I get on the throttle, the tranny shifts like I drive a manual.