4L80E conversion

[GR8-68]

So I have been doing a lot of research on converting my th400 over to a 4 spd auto. So a fellow worker today told me he had a 4L80E with 40,000 original miles on it he would sell me for 300. To me it sounded like a decent deal but not really up on the pricing range on these.
Also what is involved in getting it to work behind a sbc 350? I have read the easiest and cheapest way to go is the 91 -93 6.2 6.5 diesel trans computer. There is just to many opinions on the internet to seem to get a solid true answer.

[46stude]

What's your rear gear ratio? That's the whole trick to an OD swap.

Biggest mistake I've made is swapping to a 4L60e when the TH350 burnt up in my Cheyenne. 3.08 gears & OD is useless. I have to keep it in Drive, which is a 1:1 ratio just like Drive is in the TH350, because even at 80+ mph it'll hunt back & forth between OD and Drive.

I shoulda just had the TH350 rebuilt & spent my $$ elsewhere.

[jjzepplin]

Swap those 3.08s for 3.73s and your trucks life will begin again.

[46stude]

That was my point- it's a slippery slope once you do the swap. I didn't "need" the 4L60e. I had it, so I swapped it in. Now I have $$ tied up in the shortening of my driveshaft & the purchase of the transmission controller, not to mention stuff to run an electric speedo. It still needs different gears, which is more $$.

So if the OP's got 3.08s & there's nothing wrong w/ the TH400, I'd suggest sticking w/ the 400.

[Heavymetl]

I love the 4L80E. Same gear ratios as the TH400 and tough as nails with a nice overdrive. Much preferred over the deep first gear and weaker design on the 60E.

That being said, running one behind a non-computer controlled engine is something I've never done. Piece of cake with an LS and ECU, not sure what the best answer is otherwise. I can't imagine using a 26 year old factory computer would be anything but a massive headache though.

[LongBox]

If I was in this position, and with a favourable rear gear ratio, I'd be interested to know if there is a "box" that let's you shift the trans manually, sort of like letting your brain do the computing. Paddle shifters would be the modern way to think of this.

[weq92f]

Yes there are some folks out there doing stuff like shifts with buttons ( paddle ) and displaying data just like some later ( 4l80e ) GM trucks. It can be done.

-klb

[special-K]

If someone has 3.08s they don't need O/D. The cheapest controller is a used factory 91-93 diesel ECM because those were the first years of 4L80E and the last years of mechanical injector pump. The easiest controller is an aftermarket controller for several hundred dollars. There is also the manual valve body option. Another thing to consider is speedometer. The 4L80E requires an electronic speedo. You'll have no drive for your cable. I think there is an electronic adapter or you could use a GPS speedo. I'm weak on electronic and haven't done this swap. I know Lock Doc has... I think?

$300 is a great price for the transmission, but there's more to spend.

[Bigdav160]

The Mircosquirt can control transmissions.

I am not sure why they charge $100-$150 more for the transmission harness version

[weq92f]

For the speedo, it's possible to purchase a "box" that takes the electronic input from the 4LXXe and spins a speedo cable.

Here's another route to achieve the same thing:
http://www.shiftworks.com/tailhousing.htm#4l80E

-klb

[davepl]

I have the 4L80E behind my 402. I love it. I run 4.10s plus the trans overdrive and it works well. Tons of gear in town and then it settles right down on the highway or cruising.

I use the TCI-TCU controller box, which I have no complaints with.

I also use a (different)TCI box plugged into the TCU to spin the speedo cable and drive the factory speedometer. That's about $600 on its own. If I had it to do over again I would buy the tailhousing for the 4L80E that has the speedo port built in. That too is $600 which is a complete gouge but I think it's simpler. My needle has a lot of bounce and I don't know if that's from the electric box or the routing of the cable under the dash, but it's the only downside I can think of.

Otherwise, great trans. I had to adapt my shift linkage, which works great now, and to turn the trans mount around. I then had to shorten the front half of my two-piece driveshaft.

[GR8-68]

I am running 4:11's the reason I am wanting to do an OD transmission. I bought the 4L80E for 300, it appears the easiest way for the speedo conversion is to just buy the mechanical tail housing, not cheap but a one time buy and no electronics to deal with there, I may gowith the 93 diesel trans comp to work the rest just have to locate a harness.

[jocko]

With 4.11, definitely a worthwhile swap - and I believe your plan outlined above is the best approach. Keep everything mechanical that CAN be kept or made mechanical, and then computerize whatever is left for things for which you have no other option.

[chevy72blu]

Not mentioned and expensive, but if you want a pre-engineered solution there is always Gear Vendors Overdrive.

[DBK81]

Be sure to post up here your swap and all the details, thinking of dumping my TH400 as well and this would be the route to go, interested to see how the trans comp install goes.

[46stude]

Originally Posted by davepl

I use the TCI-TCU controller box, which I have no complaints with.

That's what I'm running with my 4L60e. No complaints here either. I looked into just about every option I could find, & the FAST/TCI controller seemed the best bet. Not the cheapest route, but not the highest dollar route. I'm cheap, but research into a modified diesel computer, it just didn't look like a real reliable or easy situation.

[GR8-68]

Originally Posted by chevy72blu

Not mentioned and expensive, but if you want a pre-engineered solution there is always Gear Vendors Overdrive.

I have looked at those not much cheaper and something just doesn't seem right with that.. Any reviews from anyone who has done the Gear Vendors overdrive unit ?

[46stude]

I just remembered one other expense we've not mentioned: you will need a throttle position sensor to let the trans computer know when to shift. About $130, depending who's you buy. Or you can make your own for less than probably $75.

[kwmech]

Originally Posted by GR8-68

.. Any reviews from anyone who has done the Gear Vendors overdrive unit ?

I've done a GV unit in my 69 2wd flatbed, (carb'd 454) behind a T400. Works awesome. However I am looking at doing a 4L80 in my suburban (4wd TBI 350)

[GR8-68]

Originally Posted by kwmech

I've done a GV unit in my 69 2wd flatbed, (carb'd 454) behind a T400. Works awesome. However I am looking at doing a 4L80 in my suburban (4wd TBI 350)

Thanks , so is it all mechanical or is it also computerized ?

[HO455]

The gearvendors is a two speed splitter that is electrically controlled. The control can be as simple as a toggle switch or more complex wiring tied into the brakes, or use their electronic controller. The unit is pretty bullet proof and not hard to rebuild if necessary. The only downside over one of the O/D automatic transmissions is no lockup convertor. I have one with a 727 mopar tranny.

[Overdriven]

http://www.efisource.com/shop/micros...transmissions/

Fully customizable controller with preloaded base map and harness. Connect to a laptop and tune with free software. Not sure what the diesel 4L80 controller and harness go for but this is $450 and looks complete. It doesn't mention sensors being included so you'd need to check on that though.

[GR8-68]

Thanks guys this is some helpful information. I also found this msd makes a tcm control module kind of pricey though as you have to buy separate components to put it together

MSD TCM

[GR8-68]

Originally Posted by Overdriven

http://www.efisource.com/shop/micros...transmissions/

Fully customizable controller with preloaded base map and harness. Connect to a laptop and tune with free software. Not sure what the diesel 4L80 controller and harness go for but this is $450 and looks complete. It doesn't mention sensors being included so you'd need to check on that though.

That is a real good source, and about the best pricing for an aftermarket I have seen. The diesel control module is around 125 but then you still need to buy the harness.

[GR8-68]

Also found this controller on ebay for 475.00

atcFOUR controller