Choice of Auto trans for 750 ft.lbs FI BBC set-up

[g356gear]

Looking for recommendations on the best choice of auto tranny to run for forced induction BBC that can handle around 750 ft.lbs. I curently have the stock Turbo 400 in my 69 Camaro, but am looking ahead to getting something that handle a FI BBC. Also looking for a recommended stall for going to a turbo application. Thanks for the input.

[1969CamaroRS]

What about a built Bowler 4L85E (1000ft/lbs) with Twist Machine paddle shifters,

Keep that rpm right in the powerband between near instant shifts:


http://bowlertransmissions.com/itemdetails.aspx?iid=13



http://twistmachine.com/shopping/ind...&products_id=6





Thread on PT discussing Manumatic technology:
https://www.pro-touring.com/forum/showthread.php?t=5519


I have the 4L65E version with paddle shifters, hoping to be up and running soon. If you have questions I'd give Steve "streetfytr68" a pm. Great guy and top notch customer service.

[g356gear]

Thanks for the info. I would like to retain the stock shifter/console if possible. Any idea what would be needed to swap in the 4l85E transmission and what extent of modifications would be required. (Eg tunnel, driveshaft, etc )

[Steve Chryssos]

Thanks Ed!!

750 FtLbs is definitely 4L80E territory. And you will need a built 4L80E. Or a built TH400, but you will lose overdrive, converter lock up, tuning capability and paddle shift capability. 750 HP big blocks aren't cheap. The same holds true for a 4L80E that can handle that level of input torque.

If you have a stock clip, there are no tunnel mods required. Most aftermarket clips, on the other hand, raise the engine slightly to accommodate a front mount steering rack. Minor massaging with a hammer/dolly is required in the bellhousing area. That's only if you have an aftermarket clip. Console and shifter is not a problem using a Shiftworks 4l60E kit. Some extra time spent with linkage adjustment is required for the 80 to ensure that the shifter moves all the way from park to 1st gear.

When setting up a converter for turbo applications, a dyno sheet is preferred on top of the usual engine/vehicle/usage spec analysis. Best to know at what rpm boost comes in. On turbo apps, the dyno sheet is also useful for transmission calibration although trans calibration is way easier to adjust than a converter stall change. Feel free to pick my brain. Call, email or post here.

[g356gear]

After doing a little more rsearch on the 4L80E I think that may be the choice that I should go to in order to get the power levels I need to handle and still fit in the car. Yes it is a stock sub and body.

Essentially what I would be looking for is a "grocery list" for installing a 4L80E into a 69 Camaro ready to drive. If anyone can chime in with info that would be great!

[Jake's Performance]

I've done the 4L80E's in a few 1st Gen F-bodies.

We did one in a '69 'Bird with 6.0 LSx engine. Also have one in a '68 Camaro with SBC.

They fit the tunnel surprisingly well on the 1st Gen cars.

750 HP doesn't require anything super fancy for the 4L80E. All the same mods you do to the TH400, good friction materials, proper hydraulics, good clearances, rollerize the output and fwd drum locations, HD snap ring for the intermediates..

We build quite a few 4L80E's for high HP applications.

Check out the website under the projects section, pictures of a 1200 RWHP 4L80E and components.

http://www.jakesperformance.com/Projects.html

[g356gear]

Anyone have any parts list of what is required to get this tranny in a 69?

[Jake's Performance]

You'll need a crossmember (G-force, BTO, custom built), you'll need a driveshaft with 32 spline yoke ( I use a 4" steel NASCAR takeout shaft usually), either a full manual valve body trans or a controller (controller is available from Baumman, Compushift, TCI, Big Stuff 3, Megasquirt, etc).
Possibly a mechanical speedo kit, a torque converter, shifter mods or kit (Shiftworks).

[Steve Chryssos]

That about covers it. Not sure if G-Force has a 67-69 to 4L80E Crossmember. Hopefully they do. If not PATC Raptor-X Crossmember. If you end up with an early case 4L80E I like Russell 612000 adapter fittings to save space between case and tunnel. It's an all in one adapter and hose end.

[Jake's Performance]

The case threads are not NPT. I prefer to use the correct thread and not risk breaking a case.

[Steve Chryssos]

Early cases are 1/4-18 pipe. No O-ring or flare.

[Jake's Performance]

Steve,
Come on now, do I really need to school you on what size the threads are in a transmission case?

How many have you rebuilt?

GM hasn't used NPT on a transmission case for about 40 years.

If you want to potentially ruin a transmission case and use NPT be my guest, however please don't spread false information.

If you recommend NPT for one of my customers and they ruin a case are YOU going to pay the $300-700 core charge on a 4L80E, plus a couple of hundred to recase it, plus shipping two ways?

Please stick to what you know.

[1969CamaroRS]

I had 1/4 NPT on both my 4L60 and 700R4... In fact they both came with adapters to compression fittings with the end threaded into the case being 1/4 NPT, which I replaced with 1/4" NPT to -6 AN fitting.

Even TCI lists 1/4 NPT in their online docs:
http://www.tciauto.com/Products/Tech...r_fittings.asp

Looking through other docs seems to indicate they could come with either 1/4" NPT or 1/2" UNF thread with washer seals.

Maybe they aren't all the same?!?

[Jake's Performance]

I had 1/4 NPT on both my 4L60 and 700R4... In fact they both came with adapters to compression fittings with the end threaded into the case being 1/4 NPT, which I replaced with 1/4" NPT to -6 AN fitting.

Even TCI lists 1/4 NPT in their online docs:
http://www.tciauto.com/Products/Tech...r_fittings.asp

Looking through other docs seems to indicate they could come with either 1/4" NPT or 1/2" UNF thread with washer seals.

Maybe they aren't all the same?!?

I don't see NPT on the TCI site, I see "pipe". There are different pipe threads, NPT is tapered.

Show me a OEM transmission fitting that is tapered. Particularly a 4L80E or any GM transmission made since the early 70's that has a tapered cooler line fitting.

Guys,
I do this for a living, I've been building performance GM automatics for over 15 yrs, I'm not here to spread disinformation and I prefer not to see hack work done to a well designed piece of equipment.
I'm not pulling this stuff out of my arse.

The "taper" on a NPT fitting is the problem, you are screwing a tapered fitting into a tapped hole in an aluminum case that is NOT tapered.

Anybody willing to place a wager on the threads of a 4L80E case?
I would be willing to bet more than most people's monthly salary, because I KNOW what they are.

I'm not guessing, I'm not basing what I think on what I read on the internet or saw on a vendors site or catalog.

Yes it is 1/4" pipe thread with 18 threads per inch, but it is NOT NPT and NPT has a good chance of causing damage and/or leaking.

I don't thread metric bolts in a SAE hole or vice versa, I don't do hack work, and I'm not here to spread false information intentionally or unintentionally.

I don't believe Steve is either but he has done so in this case.

If there was no issue with running NPT, then I wouldn't say anything.

NPT relies on the taper to seal the pressure/fluid, OEMs went away from this type of fitting decades ago for a reason.

Buy the correct fittings, specifically designed for a transmission (NPSM) and don't risk the case.

Just because there isn't a gasket, seal, or taper, doesn't mean it's NPT.

A few links:
http://www.russellperformance.com/mi...any/pdf/47.pdf

http://www.summitracing.com/parts/ATI-925137/

(note at bottom: ATI has filled a needed void with their 1/4 in. NPSM (straight) thread transmission cooler line fittings. Using the proper straight thread fitting can prevent the case cracks associated with trying to install tapered pipe thread fittings and quite possibly save you hundreds of dollars in repairs! )

[Steve Chryssos]

Take me to school Jake. I'm okay with that. I've been using that 612000 for years with no leaks or cracks. Teflon paste and the soft aluminum used in the Russell fitting probably saved me.

But wrong is wrong. I'll recommend the ATI fittings for now on.
Thanks

[1969CamaroRS]

I guess my confusion would be I always had NPT (national pipe thread) = pipe thread (taper). I was aware of NPTF without a taper. But usually I thought when referring to pipe thread it was the convention to list the standard if it was if its not NPT.

http://en.wikipedia.org/wiki/Pipe_thread
http://encyclopedia.thefreedictionary.com/Pipe+Thread

Not saying your wrong but I could swear that the fittings I pulled off both my trans had a taper on them (looked at them pretty closely).

*edit* I dug through and finally found the fittings I took off my new 4L65E and its definitely a NPT fitting, its got a taper.

Must be a very common error then. I tend to use a good Snap-On torque wrench for everything maybe why I didn't break anything.


Thanks for the info.

[Jake's Performance]

Russell makes the correct fitting as well and it's cheaper than the ATI one (better looking too).

[AJSZR2326]

why wouldnt you go for a 6 speed?

[g356gear]

why wouldnt you go for a 6 speed?

The car is an original Turbo 400 car and I really don't want to cut it up to go 6spd.

[Jake's Performance]

*edit* I dug through and finally found the fittings I took off my new 4L65E and its definitely a NPT fitting, its got a taper.

OEM fittings are definitely not NPT, so if you got a 4l65E from GM, the fittings (snap in type) are straight thread.

The last transmission GM used NPT fittings on that I've seen were the very early TH350's, 1969-1970 ish.

When you see these, they are obvious because there is typically still some thread showing.

The straight thread fittings bottom out on the case. Some have the nylon washers to help seal but most no longer use any washer.

It is commonly confused because most people aren't familiar with all the different type of hydraulic fittings, their nomenclature, and usage. I have had a crash course in hydraulic fittings working on submersible ROV's. When you are working in 4000 psi ambient and then cranking 3000+ psi, your plumbing has to be right.

It doesn't help when vendors advertise the wrong part or mislabel the correct part.
Many vendors sell the right fittings but still call it NPT, when it is not NPT.

NPSM.