besides the trans, converter and shifter, how expensive is the project?

 

ttt

Also, is the 700r4 any stronger than the 4l60e? worthwhile going this route at all?

 

With the few mods you have you should to be able to get a 4L60E/700R4 to work fine. I wouldn't swap to a TH400 if I were you... I did the TH400 swap for about the same price as a rebuild on the stock tranny. You'll need a new driveshaft, torque arm that doesn't mount to the tranny, speed sensor and reluctor for the speedo to work, M6 tranny xmbr, and a reprogram to keep the DTC codes away.

 

Well, I also have a 150 shot of juice, long tubes with true duals, and a cam/head swap coming soon too... Juice is already installed...I just haven't used it yet. Exhaust is done too

 

Some other things that may cost you more $$$, depending on how fast you plan to go:

-SFI flex plate
-manual valve body
-Ultrabell or flexplate shield
-case shield
-dipstick
-pan (may not come with tranny)
-cooler

And things like the cross-member, VSS, driveshaft, shifter, etc as mentioned above.

And... if you don't like revving the snot out of it in 3rd gear, a Gear Vendor O/D unit.....

 

does the slip yoke need to be changed on the driveshaft or does the DS simply need to be shortened and rebalanced?

I have a shifter already. I'm not worried about the flexplate YET if it will bolt to the TC without issue. The manual valvebody and other stuff can wait as well. And as far as OD, the car can see 90% local use if I go that route...

What do the VSS and cross member cost?

 

There is a very large range in cost, depending what you need/want. A decent street TH400 can be had for less than $1,000. A basic race unit is in the $1,200-1,500 range. Mine doesn't quite have the best of everything, but ran a bit over $3,000. An absolute top-of-the-line TH400 is in the $4,000-4,500 range. A torque converter can similarly run from ~$500 to $1,500 or more. Added to the tranny and converter you need a shifter, tranny cooler, and a new driveshaft. A tranny shield is a nice option. Figure between $2,000 to $6,000 or even a bit more if you really go nuts. The speed sensor parts are around $150 and I fabbed up an X-member from stuff I had. I think you can buy a one for ~$150 or so.

Of course, as Fred posted, if you do this you will have a 1:1 top gear. Depending on your rear end this may leave the car anywhere from tolerable to "fugedaboudit" for street use. In my case, I use a 3.42 rear end and it is in the "tolerable" category, though I haven't driven it much yet on the street. The options for an OD are not so great. The Gear Vendors unit is supposed to be well near indestuctible, but it's heavy and costly (over $2,000). You can probably get a 4L80E to work. The 4L80E is an OD version of the TH400. It is quite bulky and heavy. Built to the same specs as a TH400 it would be a bit more expensive, but not a lot. I strongly considered a 4L80E but ended up going with the tried and true TH400. Now, I am having a problem getting a converter to do what I want, but that's another story.

Rich Krause

 

There is a specific slip yoke for the TH400, so you need that, and a shorter shaft.

The lack of O/D gets a bit tiring when its turning almost 4,000rpm at 70mph, with 4.10 gears and 25.6" street tires.....

I believe there might be an adapter that allows you to use the stock torque arm.

Madman Racing sells a dipstick that actually fits (the Lokar is very short, and ends up under the cowl) and a cross-member, but there's no reason to not just make one out of an M6 piece.

 

I was told the 4L80E wouldn't fit under a 4th gen because the bellhousing is too large. I imagine the size is the same for a TH400. Did you guys need to do any clearancing to get the TH400 to fit?

 

There was no clearancing needed for the TH400. It fits fine even with the CSI tranny shield. I did drill a hole in the tranny tunnel to get access to the upper left side bellhousing bolt in order to be able to remove the tranny without dropping the cradle. The bolt could not be backed out all the way even with tipping the tail of the tranny down. The dimensions are as follows.

Overal length: TH400 28 3/8" 4L80 32 11/16
Bellhousing diameter: 20" for both trannys
Length minus tailshaft: TH400 24 5/16" 4L80 26"

However, the "body" of the 4L80 is larger diameter than the TH400 also. I don't have this dimension.

Rich Krause

 

Ditto.... .no problems fitting it in the tunnel. I have the Ultrabell, and a TCI tranny case shield. No problems.

TH400 + GV

 

D@mn, that looks nice. Mmmmm, Gear Vendors....

 

If you use a th350 w/ a longer tailshaft will you still need to have another DS made?
Scott

 

A TH350 with a 9" tailshaft ends up the same lenght so the driveshaft length should work. Not sure about the yoke.

 

ok good thats what I thought, I am putting in a built th350 in the next week then.
Scott