Trans Questions Part Duex
 

Ok, still up in the air about the trans I wanna throw behind the new engine.

Options are, 4L60E, 4L80E, TH400, or TH400/GV combo

Option 1: 4L60E costs $2925 with a 2 year warranty, and would require just a reflash of current converter. Downside is, google fast cars with 4L60Es and, you do not see many, if any at all. They are not meant to be raced and this is a factor in my choice. Upside is, it would obviously bolt right up and require no mods.

Option 2: 4L80E costs $2200 for a 1 year warranty, and would require a trans crossmember at $170 and a new converter at $845. OR, a full "kit" which covers all the stuff I need to swap it in for $3500 and also gives a 2 year warranty. The trans can handle more than I plan on throwing at it, and comes standard with a T brake, BUT, will require cutting/BFH mod to the trans tunnel.

Option 3: TH400 costs $2500 with no warranty(local used unit) but would come with everything I need to bolt in and go. Converter would need to be restalled. Upside it would also handle anything I throw at it but, I lose OD and lock up.

Option 4: TH400 with GV unit, not really a practical option as it would cost well over 5k to and I could easily just do a 4L80E for less.


So, at this point I am wondering how much value I place in lock up and OD in the trans. Granted cars came with 3 speed transmissions well before this so it can be done, just curious how people would feel in this situation given the options.

You've stated the options but didn't mention your intentions with the car.

Based on our convos I would go 4L80E for the following reasons:

- sounds like it's overkill but I think that's a good thing.
- if you sold the converter you have, you would be close in price to the built 4L60E
- you would have OD
- taking a hammer to your car would be worth it for all the benefits
- I assume this would be a new unit rather than a used TH400 (told me never buy a used trans)

Usage is key, absolutely.

Do you really need a lot of floor massaging for that? (not saying you are wrong, just asking). I know that trans slips into a lot of older cars w/o issue. Just as a for instance the t56 in my 77 required all sorts of surgery, but a 4L80E in a 2nd gen appears to require none. I have seen on some older cars some fairly minor floor hammering depending on which 4L80E you get as the coolant lines were relocated at one point.

th400 vs 4L80E
http://i57.photobucket.com/albums/g2...8/DSC02616.jpg

My $0.02 is if it is a street car that gets driven more than 20 minutes go 4L80E. If it is just a drag car getting towed then th400.

I have not checked prices, but $2500 for a used TH400 seems steep to me unless you know the whole history of that trans.

You need to cut a port for the wire harness going into trans, ears need to be cut off the trans and a few select areas need to be massaged.

So I guess you guys are implying that driving highway stuff without OD/lockup will get old fast?

And BLS, this is for a friends project

Does the 4l80e come with a stand alone computer for that price? If so, that seems like a good deal to me. What is the HP rating? Have you see what is involved with the hump surgery? I wouldn't be opposed to cutting and welding if I owned your car. Provided it is done properly.

No, the trans would bhe controlled via the PCM. Trans is rated at 750hp

:wink:

Matt:

I don't know if this is still the plan but you mentioned that you would be running 3.08 gears in your rear axle, so I'm just gonna throw that out there.

Personally I'd go 4L80E without much thought. TH400 with a GV is nice but that's basically a 4L80E anyway.

And to be honest, fab work will be required when you are throwing around some decent chunks of change and looking to go out of the normal "zone" like this. And unless it's really minor clearancing I'd look to cut and weld over a lot of hammering. Do it nice the first time.

I may bump it to a 3.42 gear set, but with OD, at 75mph thats roughly 2300rpm, which you can't beat.

Just to let you know, in your application, engine load is a must!!! OD trans has been proven to work, But T400 w/3:08 gears works exceptionally well.

Are you going with an LT1 Boost kit?

Yea I know Curt, hence the lower gear set, 3.08/3.23 pending rear end brand and available gear sets

4L80E. You drive your car a lot (when it works).

:bertstare:

Matt.... ummm I have a T400 just hanging out here on shelf. I was going to use it my car, I just cant persuade myself to give up rowing gears. I'll give ya a screaming deal on it.

I just am not sure whether I am able to give up OD and highway cruising yet Curt, gotta call a builder tmmr and I will let you know.

T400 & 3:08's are perfect, nice cruising on highway. Ask a couple FI guys on tech.
My Brother has T400 with 3:23's in his 02 WS6 and goes down GSP with it from howell to my house all the time. But I like the 3:08's a bit better due to lower rpms at 70-75mph

How is his rpms around town, red light to red light though?

th400 will be quicker racing too....

He is not building a full out race car though, so that won't really matter all that much.

N/A Ls2 motor 534hp t400 3:23's runs around 2900-3000 rpms @ 70+mph

Turbo'ed t400 3:08's ran 2600-2700 rpms @ 70+mph

neither one was bad at all from red light to red light.. try it with a stock motor and sure it will be a dog.
I believe both were with a 28" tire

YOU DONT NEED GEAR FOR A TURBO CAR!!! The lower the gear the better in most cases.

Also cheaper for parts, more reliable, & can withstand more HP than a A4

p.s. if you only want to spend your money once & have room to grow (hp wise)
1) spend a buttload on a 6l80e setup
2) spend less than half w/t400 & 3:08's
or....
you can spend a buttload on T56 and keep dumping $ into it like me....:facepalm:

a 6l80E Curt?

I was asking because Fastbird made over 750 hp with one of his kits. :bertstare:

In a manual, with a ton of meth and really pushing the poor 76gts

6L80E has no after market controller, and is tall & low so it presents packaging issues. It is not yet proving to be a good retrofit trans for the masses.

A 4L80E will let you run better rear gears and is as strong as a th400. Best of both worlds. It's a beast, it's a TH400 with 4th gear. IMO that is doing it once & right

If you do a TH400 you can probably add a gear vendors are a later date. But often later never comes.

Who is the car for?
"I may bump it to a 3.42 gear set"
"I just am not sure whether I am able to give up OD and highway cruising yet"
"He is not building a full out race car"

Now we are into gear selection, etc. Is it a turbo car? What is the total application? Is it a street car or race car? How many street miles a year on it? What is the engine RPM range?