700R4 or 4L80e

[SoupMan]

Guys, looking for opinions and experience on the subject.

My next big step is taking my reliable TH350 out and putting in a 4 gear transmission. Running a Pontiac 455 with about 410 hp/512 ft/lb at the crank. The end plan for the motor is to get it in the 550hp range but that's for later. Car is mostly a cruiser. Might track it once or twice a year for fun, not competition. Would like to go from a 2.72 rear gear to a 3.23 or higher gear while gaining the benefit or high fuel mileage.

Keeping that in mind, I've looked at the 200-4R, the 4L80e and now the 700R4.

200-4R. I had a guy I know selling a built 200-4R he never put in his 1st gen. I talked to the builder of the trans and he advised me away from that transmission. He said they are great for stock power but he said not enough was done to that transmission to support your power level and suggested it was too expensive to make it work for my future setup.

4L80e. I have good core sitting on the shop floor. To do this transmission right, I would have to get the Terminator X, all the hardware to make it work in the car and then a speedo conversion. All this will cost me close to $6,500 CAD ($4,800 USD). I might get $2,000 back from selling existing setup so call it $4,500 CAD.  That doesn't even include a decent converter. That transmission will definitely do the job.

700R4. Years ago I avoided looking at this one due to horror stories and builders being hesitant to stand behind a performance build. HOWEVER, I've noticed a shift especially with online options. I'm seeing some reasonably priced options on Jake's Transmission and other manufacturers. I think that the 700R4 is likely a bolt in compared to the 4L80e. Drive shaft, adapter place, shifter conversion kit and a rebuild kit or straight out purchase on one of these sites.

My hope is the 700R4 will work great for my setup but I'll wait to hear from you guys.

[Wallington]

Torque will kill all of them if not built. An expensive one already rebuilt to suit someone else's engine but needs going through to adjust will blow the cost out on any trans. Chat to a builder who can do from scratch in order to get a better comparison, and what other mods are required, or not, to make each work.

[SoupMan]

The 4L80e can be built to handle just over 800HP for fairly cheap (< 2k). What makes the upgrade expensive if the controls and speedometer conversion.

[5th T/A]

Torque will kill all of them if not built. An expensive one already rebuilt to suit someone else's engine but needs going through to adjust will blow the cost out on any trans. Chat to a builder who can do from scratch in order to get a better comparison, and what other mods are required, or not, to make each work.

I agree with Wallington. If you just drive on the street with stock tires, you don't have to worry so much because the wheels will spin effortlessly. But if you race at the strip with slicks you have to worry about twisting the body, especially if you have T-tops and no subframe connectors. With slicks a 10 bolt rear end it might not hold up, another costly upgrade to a 12 bolt. A heavy duty drive shaft is also a good idea.

From 1970 -1976 I worked in a transmission shop, I easily rebuilt 100's of automatics of the day and at the time was somewhat knowledgeable. Today regarding 2004R, 700R4 and 4L80E I can only talk about what I have read.

A 2004R will be easiest to install, has a BOP and Chevy bolt pattern. I am pretty sure the transmission length is the same as a turbo 350 so you can keep your driveshaft. But proper TV cable is critical, or you will burn up the transmission.

A 700R4 is stronger, you still have the TV cable to contend with. Will need a shorter drive shaft. You will need a bellhousing adapter if you run a Pontiac engine.

4L80E is the strongest. You will need an electronic shift controller, another expense. But you can easily program the shift points to what ever you want. Will need a Bellhousing adapter for a Pontiac engine and a shorter drive shaft.

With all three of the OD transmissions you will have to modify the shifter to accommodate the extra gear ratio. Afterwards the shifter ratcheting mechanism is no longer functional and the gear indicator will not light up.

Choosing the right transmission builder could be more important than what transmission you decide to install.
I'll be curious to hear what route you take. I have thought about doing an overdrive swap on my 1980 TA with a built 461. At this point in time have elected to keep the stock 2.41 axel ratio and turbo 350. I have all the performance I need, I can't get decent traction using stock tires as is and the 2.41 axel ratio gives me a low cruising RPM on the road.

[scarebird]

I had a TH200-4R behind a 462; did very well with 3.55 gears.  Stock shifter will work but you will lose ability to shift down into 1st.  TV cable if routed stock is self adjusting and not an issue.  All lockup requires is a dual outlet brake switch; can lockup all gears or just OD.

If you really are going to hammer on it the most cost efficient route is TH400 with 3.08's and a good convertor.

Another option is the TKX 5 speed - they are superb and will easily handle a 455 with the fun of a manual.

[SoupMan]

Seems I'm heading back towards the 4L80e. Assuming forward drum is good, build will run me about $1,600 USD. Builder will guarantee it with my current and future setup he says. He has a 30 years of doing this and he prefers the 4L80e over any other option as long as I'm good with the extra cost of adapting it.

As for mention of T-top, rear end and various other upgrades required to support my future power objectives, I'm well aware and the plan is to build the 10 bolt up next winter at the same time I'll be swapping the trans. My traction isn't good enough to break stuff yet so I have time to sort out the T-Top issue.

[ryeguy2006a]

Essentially the 700r4/4L60e is a turbo 350 transmission with an added overdrive. The 4L80e is a T400 transmission with an added overdrive. In stock form the 4L80e is a very strong transmission and would likely handle the 550 HP flywheel, but certainly sending it to a shop to have it build would be your best bet. As for the transmission controller, you can easily use the a stand alone controller from Quick4 or similar for substantially less than a Terminator X Max kit. There's also a guy who converts the tailshafts for 4L80e to run a cable speedo. I'm likely going to do that with my car since I really want to keep the feel of the original dash with a bouncing speedo.

Keep us posted on what you do. Also, not sure if he's around anymore, but Critter used to have a 74 Trans Am and was running a 4L80e. Maybe he could chime in, or you can send him a PM.

[SoupMan]

Rye,

Yes, I did look at those controllers but I figured it would be a cleaner setup with the Terminal X. Control all aspect of the car with one module. I like that part of it. And I'm sure I'll fetch $1000 USD for the Sniper.

As for the tailshaft, I did notice a guy on Ebay selling them but do you have a guy that will just modify yours or swap it for a converted one?  Wondering if it's more cost effective.

Project will start when the season is over. Don't want to start it during driving season.

[ryeguy2006a]

Definitely, if you are planning to go with the EFI go with the terminator x max for the integrated trans control. Another option to think about is a guy here TAKidd455 offers a Pontiac 24x conversion kit. With that kit, it converts your Pontiac motor to have the 24x and 1x cam signals required for the ECU to think it's an LS motor. Then you will have sequential port EFI, Coil near plugs and full trans integration. It would require that you either modify your current intake, or a new intake for fuel injector bungs.

[737driver]

What about the Gear Vendors Overdrive? It bolts directly to the transmission and provides a .78 Overdrive. With a 3.23 rear gear ratio that would be a pretty good overdrive. It would be worth considering for an overdrive option.
Jim

[N PRGRES]

Why not go with a gear vendors and get OD, numerous gear option and not have to worry about if it will hold up or not?