Going 4l80E, I'm off the deep end again!

MCH86GN

Well-Known Member
You better not cheat on your wife!
I sure heck better not cheat, when I bought my GN in 2008 I was in such a hurry to title the car and drive it that I didn't sign the title and my wife did. So technically the car is hers. Now I have to be a good little boy or she will take my toy away.
Although, I would really like to do this swap. I didn't realize that you could get a stand alone TCU or I never asked the question. I should have known better. I am having my shortblock rebuilt right now and when it is done, I am going to have to beef up my stock trans and limit the power out of the engine or I would rather swap in a 4L80E then a TH350 or TH400. For the simple fact that it will be a street car mainly. I already know that I will have at least rebuild my transmission and put some go fast parts, but I am also intrigued by the idea of putting newer technology in my car, the LC2 notwithstanding.
 
So the dipstick arrived today, my guess was pretty good, it was only a half quart low. The problem is that reverse still doesn't work quite right, so I put the pressure gauge on the trans, sure enough the pressures read low in park, reverse and drive. I decided to unplug the tcu and I was finally seeing the correct pressures of about 270 in reverse and around 180-190 in drive. I honestly don't know what the issue is but I'm thinking I may have a bad force motor on the valve body. I'm gonna call TCI tomorrow to see if they have any clue what could be causing this.

Paul

6/11/13 update: Thanks to Don at TCI, I kthink I know what the problem is. It seems that the TCU is not getting a tach signal even though I plugged it into the green plug behind the alternator. I'll mess with it tonight and let you guys know when I figure it out.
 
Looks like I need to buy the tach signal amplifier from casper's since the stock signal is 7 volts and Don and Kevin at TCI think that it's too low to work with the TCU. Either way, we don't think that going to solve the low pressure issue so I'm going to replace the force motor on the valve body. Hopefully the parts will come in before this weekend...

Paul
 
Well we ruled out the force motor due to all other pressures (after second pressure test) being perfect except for reverse (100PSI). I've checked the reverse servo seals and pistons and all seems ok. I went back and checked all the check balls on and in the valve body and that seemed correct. I'm running out of ideas fast. The car works but reverse has a delay and slips a bit. Could the reverse booster valve in the pump cause this? I put in one of those Sonnax units and I remember it being kinda hard to move in the bore. If no one has any ideas I may just let it ride since it technically works but I'd hate to cause I know something isn't quite right. Any help would be greatly appreciated.

Paul
 
The Casper tach signal amp came in today and it works great! Finally got to take her out and do some full throttle runs. I've set the shift point at 5100 and boost set at 19. Everything is working perfect, no knock and the shifts are nice and firm. I guess I'm going to have to learn to live with the slow reverse engagement... I do feel like I may have a little too much converter for my te44 so ill probably have to upgrade to a 6466 turbo:). I'm calling this stage of the project done and will now work towards getting rid of my terrible wheel hop and replacing the steering components.
 

Chuck Leeper

Toxic old bastard
Staff member
" getting rid of my terrible wheel hop".........Caltracs are a sure fire way to do that!
I have them on my 55 Chevy & the 65 Belve. The Hemi car is a 5 speed, and the 55 is a 4L60E. Both take all you can throw at them and just HOOK...
 

Roger

Active Member
Interested

Seems like a lot of $$$. My 4L60 in my stock V6 truck is not holding up.

Why not go for a 6L80e or an Allison.
 
Just to update everyone, the transmission is still working great except for that little reverse issue. It's really nice having the ability to adjust the shift firmness at the push of a button. My initial assessment of the convertor being too loose was way off, it's actually a little tight. I guess maybe the tires were spinning and it felt like a loose convertor.... yeah that's what happened. My convertor was originally spec'd for a turbo SBC, not a turbo 6 so I'm guessing that's why it only brake stalls at 0 boost/vac to 2200 rpm. I'm still looking to invest in the TCI paddle shifter so I can take advantage of manual mode but that'll have to wait till I get some more cash. Long story short, if you're considering doing this swap I can say with experience now that I think it's worth the additional cost over the 200.

Paul
 
I have been following this thread since you started and have two questions you or someone else may be able to answer.

1st) how can you tap into the vss without the controller system you bought? I am wanting to convert a 4l80e to manual.
2nd) I have the gnx style dash with a cable for the speedometer how can this me hooked up to the electronic transmission? Or do I need to switch back to a digital dash?

Thanks for the help


Posted from the TurboBuick.Com mobile app
 

Chuck Leeper

Toxic old bastard
Staff member
I have been following this thread since you started and have two questions you or someone else may be able to answer.

1st) how can you tap into the vss without the controller system you bought? I am wanting to convert a 4l80e to manual.
2nd) I have the gnx style dash with a cable for the speedometer how can this me hooked up to the electronic transmission? Or do I need to switch back to a digital dash?

Thanks for the help


Posted from the TurboBuick.Com mobile app
Take a look at what Jake has to offer. he may well be able to do all you want.
http://jakesperformance.com/4L80E.html
 
I have been following this thread since you started and have two questions you or someone else may be able to answer.

1st) how can you tap into the vss without the controller system you bought? I am wanting to convert a 4l80e to manual.
2nd) I have the gnx style dash with a cable for the speedometer how can this me hooked up to the electronic transmission? Or do I need to switch back to a digital dash?

Thanks for the help


Posted from the TurboBuick.Com mobile app

To be honest I'm unfamiliar with the non digital dashes but if they are the same as the digital in how they convert the mechanical signal to an electrical one then the following answers should be correct.

1. I don't think you can tap into the VSS without using a computer of some sort that can change the VSS output because the 4l80e output is 4000ppm and our buicks use a 2000ppm signal. If you where able to get it to hook up your car would think it was going twice as fast as it actually was.
2. Jake sells a mechanical speedometer tailhousing kit that is modified to use a speedometer cable. If you want to avoid a computer and keep your current gauges fully operational, this is probably your best bet. I'll warn you though, it's not cheap... I thought about this option originally but figured out a work around since I had the digital dash. (only thing is my odometer doesn't work anymore).

Paul
 

chris kirk

Active Member
Can you use any exhaust? Does it have to be a be a single four inch exhaust. It looks like this build has a four inch exhaust on it.
 
Chris,

If your talking about my build, it's a single 3". I modified the stock crossmember and moved it back a couple inches so I would assume that any exhaust that works with the stock setup would work with this.

Paul
 

Major Nutz

Active Member
Great info in here. Can you post a close pic of how you mounted the trans cooler? I need options after going to a front mount. A part number would be great as mine won't fit where yours is.
Thanks,
Mike
 
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