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4L80E Questions

9135 Views 16 Replies 6 Participants Last post by  Machman
I've decided that I'm going to be bolting an automatic to the back of my 4BT. I can drive stick, and you can call me a pansy all you want, but I REALLY don't wanna sing "row, row, row your truck" every day during my commute on surface streets through downtown Knoxville.

And, while the intended recipient of this repower currently has a 700R4 that has delivered sterling service, I'm thinking that for the long run a 4L80E might be better. If I can get more power via turning a few screws, it's likely those screws will get turned. 4L80E seems to be the answer if you're adding more power.

Don't get me wrong.. The 700R4 I have now is at 220K and shows no signs of giving up anytime soon. When my Dad had it, it spent a significant amount of time with a 30' camper dragging behind throughout the US, Canada, and Mexico. In overdrive... When it wasn't doing that, it was just as likely to be at Lowe's getting WAAAAAAY too much ready-mix or lumber loaded on it. When I got the truck, the transmission fluid was a rich brown color, with a burnt nutty aroma. I asked Dad if he'd maybe gone a bit over the recommended interval for fluid change.. "It's not been changed since it boiled over on that hill at around 25K miles.." As I look down at the odometer showing 130K at that point..

Anyway, in the process of researching the 4L80E option, I've run into one $nag: The controller.

Yes, I'm fully aware of the Compushift offering, but my wallet has to breathe slowly in a paper bag every time I look at the price tag on one of those. Other companies' offerings are similarly priced. Also, I'm not interested in the full-manual conversion on the 4L80E for this vehicle.

So, in the quest for doing things a bit cheaper, and from the angle of repair parts availability in the event of a breakdown, I'm wondering about the stand-alone controller that was used on the diesel (and some gassers, possibly??) 4L80E equipped trucks in the 92-93 or 94 years.

The controller itself seems to be readily available:

GM Part number: 16147609

Standard Auto # TCM609


Pricing for that is more in line with me eating something other than Ramen for an extended period (not that I'd REALLY be harmed with a bit o' weight loss - might get me another .2 MPG or some such, too..). In fact, the pricing I've seen would allow me to carry a spare! But, there are some questions I've not been able to answer through Google and looking here:

1. Has someone actually used the factory controller for the 4L80E behind a 4B/6B w/ VE pump? And, how do you like it?

2. What is needed, besides the controller? Obviously, we're talking a wiring harness of some sort, and from what I've read so far, there's going to be a TPS needed. I also suspect a tach signal would be desired. Anything else? Schematics / wiring diagrams / pictures / part numbers / sources would be GREAT.

3. Programming / tuning needed?? I have no issues with doing a PROM burn, but wanna know up front if I'm going to need to set up for that..

4. What are the differences, if any, between a 4L80E for gas and one that is for diesel? I know we're probably talking torque converter stall speed, but anything significant?

Anyway, any info is appreciated..
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1 - 8 of 17 Posts has the TCM609 for $137.79 including the $50 core..

That's the real interest point for me..
That is a thought.

Automation of lockup on 47RH would be a relay, mebbby a WOT switch, not much else unless what I've read is wrong.

I'm just looking at what I've got sitting in the yard and what I can do with it, and what's going to be the most straight-forward swap with what I currently have in hand. (Read: Minimum part hunting, swapping, etc.)

Also, we're talking a 4BT here.. TH400's seem to survive behind them, so I'd say that a 4L80E would do OK, too. Besides, if I were looking at enough power to put a hurtin' on a 4L80E, I'd probably go ahead and pony up for an Allison 1000.

If anyone has killed a 4L80E with a 4BT, I'd be interested in hearing about it before I get too far along the path.. (Well, killed it in normal use where another similar class tranny would have held up. Give me the right situation, and I can break ANYTHING if I try..)
If I'm right, the brake switch setup is the same as what's on my truck currently to handle the 700R4 lockup input. (Just checked, and the same brake switch covers 88-93, 1/2 through 1 ton truck, 2x4 and 4x4, no alternate for tranny type)

It's true that the aftermarket controllers do things that the stock controller won't.

Building wiring harnesses, interpreting / creating wiring diagrams, and anything else electrical doesn't bug me. It's actually something I enjoy doing. (Which is a good thing, as I also have a penchant for European cars, and nothing on the planet requires rewiring as a "periodic maintenance" item like a Volvo or old VW..)

If all it needs is TPS, TOSS, CLT, Tach, Brake, and the main transmission connection, then it shouldn't be too bad, from a wiring standpoint. Getting the end(s) to connect to the TCM itself could prove entertaining, but the rest of it is readily available.

The one that does worry me is if it wants MAP / BMAP. That could be a problem from a programming angle. (Or maybe not.. Turbo 6.5 was in the 91-93 range, too..) Reprogramming for a different redline I'm more likely to take on, if needed. (I found a site that actually listed this controller, with rom code info, but forgot to bookmark it... DOH!)

I was sorta hoping someone had done this one already, and could advise on any "gotchas" that we might not be seeing here. Looks like I'm going to have to pester a friend with full Alldata or Mitchell wiring diagrams and see what's going where. (Oh, how I wish there was an economical equivalent to the Bentley guides for US stuff..)

As for the time element.. Well, yes, time is money, but only if you could be doing something better / actually making money during that time. For me, I can't imagine a better reward for the time investment than the feeling you have when you make it all work the way you wanted.

On the Torque Converter.. I'm wondering what stall speed the ones in the TH400s are in the P-30 vans. Seems to work pretty good. (I'm thinking its around 1200?)
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(I found a site that actually listed this controller, with rom code info, but forgot to bookmark it... DOH!)
Hmm.. Actually found the site, but it doesn't list the same controller.. Gives 92-93 GM TCM number of 16128420, which I'm finding on other sites, as well. Also offers ROM code stuffs. Time to hit the cross-references. is the site I found..

I'm beginning to wonder if there's any $$ to be saved this route, though. The Compushift, with the display module, would save me having to buy two gauges right off the bat: Tachometer and Tranny Temp. There's about $200, give or take.
IIRC, you're using a 1000 RPM stall converter, right? How's that working for you?
maiden voyage SHOULD be tomorrow. got my tach up and working.
Hey! Good to see ya back on the board.. Thought we'd lost ya in a swamp or something down there. :eek:

Empty weight once finished should clock in about the same as an 18' P30?? :eek:

Time to turn the screws!
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