BlackScreaminMachine

iTrader: (17)

Good Afternoon,

I am doing research for a friend and I have search relentlessly and at this point I really need some opinions as well as techincal background.

First off a 4L60e or 4L65e swap is out. I do not care how "built they are" the car is heavy 3900 race weight, making 450 rwhp and will have a 150 shot ontop and the owner doesnt have the $$$ or time to be redoing the tranny every couple of seasons.

The focus of the questions is a 4L80e or TH400 swap.

I am aware of the difference between the 2 transmission for the most part. The owner is looking for a Full manual valve body (reverse) w/ trans brake hook up. So as far as the electrical portion the PCM will not be involved.

For reference I have been using these links....

http://www.tciauto.com/Products/Tech...alculators.asp
https://ls1tech.com/forums/automatic...l80e-swap.html
https://ls1tech.com/forums/drag-raci...some-help.html
http://www.f-body.org/gears/

Basically the car has now

T-56 stock
4.10 rear gears
26" tall tire
Redline 6800 rpms

He is thinking about either trans. If it stays 4L80e the 4.10's would stay in as it has a 0.75 OD gear and if the TH400 it would have a 28" tall street and track tire and 3.42's swapped in.

He concern is the slippage in the TQ converter he was thinking a 9" Yank, 4000-4500 stall and does a TH400 have any ability to lock up as well as a manual 4L80e. I know TH400's the speedo doesnt work but can we get it to work on a 4L80e?

Also running the calculator, there is a difference in cruising speed between the 2. This is street driven, and if taken to the track it would be towed/trailered. Will see about 65 mph cruise on the freeway.

The big question is for the extra cost of the 80e swap vs the th400, which would you pick given the parameters. Making the 80e electronic is not what the person is interested.

If anyone needs clarification, let me know.

Thanks for the help.

jakeshoe

iTrader: (14)

IMO,
I would def go with a 4L80E.
First it's a late model car and as much as I love the TH400 as a trans builder, I hate to see guys go "backwards" and give up the OD.
OD transforms the old musclecars and makes them driveable, I do alot of builds and conversions for the older musclecars and usually the owners agree that they would never go back to a non-OD trans.

I would go with the 80 for several reasons, first from my understanding the T56 crossmember is a near bolt in with it, and the T56 driveline length is the same as well, so it saves cash to not deal with all the crossmember and driveline mods.

It also has the output VSS so that should be an easy fix for the speedo.

A 4L80E with a good converter and you keep lockup function as well, TH400's typically can't have lockup. PI had a kit for awhile but there wasn't enough demand for it.
CKPerformance may market one, but again, it's easier to just use what GM designed IMO.

Core prices are still high for the LS type 4L80Es unfortunately because GM is buying them up for military and SRTA requirements from the core suppliers. However the earlier cores are reasonable.
I pay a bit less than $300 for the early cores but about $700 for the late cores when I go through my core supplier.

A good converter isn't going to cost much different either way.

White.Lightning

iTrader: (53)

I'm going to a TH400 for a few reasons. First, the TH400 conversion is a lot cheaper than a 4L80 conversion. The transmission itself is more expensive, and you need to control it (even though your buddy wouldn't). I looked into a RMVB 4L80 and it was about $1k more than the TH400 built with a trans brake.

Secondly, the TH400 is so common that if the trans needs freshening up, which it will more than likely need if he is racing it, then practically every trans builder out there has the parts on a shelf and those parts are cheap.

I'm doing TH400 for the simplicity and cost savings. If I had an extra $1k-2k laying around, I would go 4L80 but I cant justify the extra money at this point.

BlackScreaminMachine

iTrader: (17)

A 4L80e doesnt have a provision for a TQ arm mount so anyone putting it in a 3rd gen or 4th gen car needs an aftermarket trans mount with the TQ arm built in.

As for the VSS, does that still work with a NON electronic 4L80e?

I recently saw LS1speed.com have TH400's listed with a lock up provision.


EATH400A Race Prepped TH400 Trans Brake, Manual Valve Body $1399.99 buy
EATH400B Race Prepped TH400 w/Lock-up Upgrade $2199.99 buy
EATH400C Race Prepped TH400 Trans Brake, Manual Vale Body, w/Lock-up Upgrade $2699.99 buy

slow67

iTrader: (2)

a th400 doesn't have a tq arm mount either.

Yes, the speedo works in the non electronic 4L80e.

tording99Z28

iTrader: (3)

I just finished up my TH400 build. It is the best thing i have ever done, I couldn't be happier. The TH400 will run you literally half the price of the 80E. Also just so you know on the TH400 the speedo will work just fine. There are a couple ways you can do it. The easiest way is to get a VSS sensor from an early 90's Truck (TH400). You will also need the correct pigtail plug for it which is like $12 and you simply cut the stock plug off and solder on the new one and plug it into the VSS. Its that simple. I just did this and it works great. Just make sure whoever you get the TH400 from puts the reluctor ring on if it doesnt already have one. I vote for the TH400 hands down simply for price. If its going to be a DD though still and have a lot of miles put on it then the 80E might be worth it since you would retain OD and lockup.

forcd ind

iTrader: (7)

i agree with Jackshoe, going backwards on a new car is kind of crazy, but to each his own
there were some old lockup 400's being built, like he said demand was low-GM actually made a lockup 350, but they were a little weaker than reg 350's as i remember
they made a switch/pitch 400, back in the 60's, dual stall, i have one sitting on the garage floor that i used last year, worked great-parts are kind of scarce, my little LS motor just didnt stall it enough
one option is a 2.75 first gear 400(not sure how much HP they can take), drop the rear ratio, but you still have the high stall, although converters are getting better at high stall cruising
i have been using 400's for 40 years, best trans ever built, but i run a 4l80e in my chevelle, love it-started out as a man. shift 4l80e, switched to a Compu Shift controller(diff v/b) great move-
why GM never just added an o/d to the 400, i'll never know, but every car out there would have one-hell, if a Co. built one, kept the cost low, they would sell them like hotcakes

White.Lightning

iTrader: (53)

I looked into a manual valve body 4L80. They are still expensive.

slow67

iTrader: (2)

Ummmm that is exactly what the 4L80E is.......shares most of it's (non-OD) internal parts with the Th400.