Usual Info on 4R70W transmission

[rangerfab]

Still on my quest to figure out to get my truck runnin & found this helpful link.

http://p71interceptor.com/tranny/diagra ... index.html

[Chris]

If you want any more info on 4R70W transmissions- internal model year differences, functionality, valve body differences, torque converters, as well as building tips. Any info you want on AODE/4R70W transmissions is here. I found this site to be very handy when building mine.


http://www.tccoa.com/articles/tranny/tr ... ndex.shtml

[rangerfab]

I read that write up as well last night but had conflicting reviews of incorrect info from other ford truck & performance forums but I did add it to my favorites. It is certainly good info to reference.

Thanks for your advice chris,
-eddie

[Chris]

What kind of incorrect info? Just wondering because I followed a number or those mods on my trans.

Now I'm nervous.....

[rangerfab]

Let me find that link....it was on an F150 forum not sure which one but il get it for you.

[rangerfab]

Here's one link but I saw another one stating the same thing but had more to it.
http://www.f150online.com/forums/transm ... ement.html

[Chris]

It's cool. If it blows up, I'll just upgrade to a T-5 like I wanted to do in the first place.

[cgrey8]

If you are looking to make big torque, consider a T56 Magnum (not the standard T56). T5s may be cheaper for sure, but stock T5s aren't that strong unless you build them up. Add to that, you can't beat the gear ratio options and the torque capacity of those aftermarket T56 Magnums. They are expensive...the tranny is more. They also require a 26-spline clutch, different bell & fork, and different yoke. At some point I want to get one, not because I need that kind of torque capacity, but because I want that super-low 6th gear to get better fuel economy. I'm expecting the entire retrofit setup to be in the $4000 range. That's a tough pill to swallow.

[Chris]

Well, my engine is mostly stock. Just mild cam and a set of lightly ported 289 heads. I think the T-56 might be a bit overkill. Plus, I already have a world class T-5. Just needs an overhaul.

Thanks for the tip, though!

[cgrey8]

The WC T5 doesn't really indicate the durability. There are dozens upon dozens of different T5s out there of varying degrees of stoutness. There were "world class" T5s that were put behind 4 cylinders and couldn't hold up to a well built V8. And there are the stronger versions that were geared and strengthened to handle a stock V8. The strongest production T5 was the one put in the Cobras. I think it is rated at 310ft-lbs. The biggest difference between the Cobra T5 and all the others is the pocket bearing on the input shaft vs standard straight needle bearing. The aftermarket T5 'Z-spec' (aka T5z) has all the Cobra upgrades and some that were never put into production to give it a 330ft-lb rating.

The T5z also has different gear ratios. One of the weak points of the T5 used in GTs was the 1st and 3rd gear. The 1st was way too steep (3.35:1 ratio) and if you did build the vehicle to get traction, you would find out that steep of a ratio was a bit more than the gears were up for. The T5z brings that 1st gear down to 2.95:1. On the top end the GT T5s have a .68 5th gear. The T5z has a .63 5th to get a little lower RPM at cruise. The gear ratios of the T5z make it comparable with the standard wide range T56, just without the T56's 5th gear. The standard T56 is still stronger checking in at 450ft-lbs although I've heard numerous reports that the production T56s didn't handle shock loads nearly as well as their spec would indicate and were notorious for breaking with engines that produce less torque than the spec when driven hard.

The Tremec TR-6060, based off the T56, fixed those issues but by the time the TR-6060 came out, things like digital dash and need for high fuel economy were common place. So for people that wanted to run a TR-6060 class transmission in an older vehicle that needed things like a speedometer gear, you needed the aftermarket equivalent of the TR-6060, marketed as the T56 Magnum. So the T56 Magnum is basically a TR-6060 with a different tailshaft and output shaft to support a speedometer gear. But to satisfy fuel economy needs, the 5th and 6th gear ratios are significantly different from the old T56. 5th is around .74 (just a little lower than stock T5s were in the 80s and 90s) and 6th gear is .50. These are the aspects of the T56 Magnum I'm most interested in. I want to get the same low gear I have with a T5z, but get an 80MPH cruising RPM in the 1700s...right now I'm at 2000RPMs@74MPH. It would be a mistake to expect my existing engine to put out at that RPM. But the high compression 331 stroker and high torque cam I've got planned should be up to that task. Of course initially, I'll run the 331 as-is with the T5. If it pulls noticeably better in the 5th I have now, then it should hold up just fine with a T56's steep 6th.

Now the real question, will it save enough fuel economy to make up for the $4000 investment? I doubt it. But I've always wanted a 6 speed. Besides, hobbies don't have to make financial sense. Right?

[Chris]

I would love to have a standard trans in my truck, 5 or 6 speed won't matter much. Just to have a stick would be awesome. It's just not in the cards right now. Maybe later I can convert but it has to stay an auto for now.

The reason I'll go with a T5 is because I already have one. I'm not going to leave it stock. It'll get the full G-Force treatment. I'd love to go with an aftermarket unit, but we must also consider the budget. Considering this thing is already several thousand dollars over budget, I'm gonna use the T5 when I do convert it.

[rangerfab]

$4,000 that is a tough pill to swallow too.....hmmm... $2,000 with nice babe at the bunny ranch then hop over to vegas & take my other $2,000 on some gambling with the hopes of hitting it big & cash in & get a T56....id say thats a nice happy thumpin easter....

[MalcolmV8]

Chris, you don't have to run a 26 spline input shaft on the T56. You can put a 10 spline in to if you want. The 10 splines are not as strong though. I twisted two of them and finally upgraded to a 26 spline and never had a problem since. I'm also putting about 510 ft/lbs and 510 hp to the tires and I drive the hell out of my car. I would say for the majority the 10 spline would hold up fine. You really have to abuse it with a lot of power to twist it. I was also using 315 drag radials and hooking really hard off the line and launching.

I also noticed you mentioned the T56 is rated at 450 ft/lbs which is correct but you say they break easily with even less power. I'm not sure where that info comes from but mine has around 35k very hard miles on it and asides from twisting the input shaft I've not broken anything inside. This is common on the 03/04 cobra forums. Not to mention I'm putting over 100 ft/lbs more to it than what it's rated for.

I did break the stock bearing retainer. It's the sleeve that sits over the input shaft inside the bell housing that the TOB rides on. I replaced it with a billet piece same time I swapped input shafts and it's been good to go ever since.

BTW I think you'll like the 6th gear. It's really low. I don't hardly ever use it though unless it's a long haul as the engine rpm goes so low you can't enjoy the exhaust rumble so I put it in 5th

[cgrey8]

The T56s with 10spline inputs were only on the regular T56s. All T56 Magnums have the 26spline. I'm not sure if the redesign made it impossible to put a 10 in or not. I would opt for a 10 since I don't drive nearly hard enough to need a 26 and I wouldn't be putting an engine nearly powerful enough to need it. Again, my ONLY reason for wanting a T56 Magnum is for the higher-end 6th than what the regular T56 and T5z offers.

As for the breaking, yours was probably one of the better ones. However the T56s that came in the Camaros and TransAms got a reputation for not holding up. A buddy of mine had one of the 2003 TransAms with a T56. He only owned the car for 10kmiles and he went through 3 sets of tires and 2 transmissions. You talk about being hard on a vehicle, he was that. I don't think the car ever drove without getting driven hard. My office still has a 100ft strip where he burned out one Saturday. I wasn't particularly happy about that.

[MalcolmV8]

Unless something is completely redesigned in the Magnum I don't see why you couldn't get the 10 spline input shaft in there. Also if you're just after the taller 6th gear I'd see if someone like D&D can just build you a regular T56 with a taller 6th gear. Seems like that should be fairly easy and save you some money.

You are probably correct about the different versions of the T56. One of my buddies used to have an early 2000 some Camaro (I forget the exact year) and his T56 looked physically different on the outside. We compared it to mine and it wasn't identical. Also now that you mention it his 3rd gear synco was hosed from his abusive driving lol.