Have you guys checked out Keisler's new RS line of transmissions?

They appear to have the saginaw/muncie/t5 bolt pattern.

They are not rotated like the T5 is, but for a race application you should probably run a scatter shield anyway.

-- Joe

 

There was a discussion of it along with the M800 McLeod is working on. General consensus is that they're repackaged T3550 (Mustang) units with TKO upgrades..

I'll stick with T56s, but YMMV..

http://www.ls1tech.com/forums/manual...ighlight=RS600

 

Hi Mike,

I had a T56 in my LT1 car a few years ago. I'm not too happy with the way it shifted, but the big cons of the T56 for ME (LT1/LS1 versions) is the aluminum bell and oddball pull clutch setup. The aftermarket T56 would be great, but it's way to long.

The Keisler unit is indead a modified T45RS/3550 GM spec transmission with better gears and a revised reverse.

I'll check out that link, thanks!

-- Joe

 

The early T56's had paper blocker rings which were a compromise at the time. Later models and rebuilds have CF blockers and shifting is much improved. The later GM T56s got triple/double cone synchros and shift smooth as butter. (I'm building a complete LSx car, for the only reason to use a triple/double cone T56... LOL)

Most all factory bellhousing will be Aluminum, but both LS1 and LT1 T56s have SFI steel replacements available now.

The LT1 pull-clutch was a space compromise around the longer T56 and the protuded block/crank of the LT1(SBC). The LS1 removed that restriction and has the same clutch/FW selection as most any other engine/trans combo.

 

Have not used an LS1 version. I have not looked at the SFI bells for the T56.

My C4 ZF6 had the same clutch style as the LT1 T56 and it was a PITA. I never bought an LS1 car so I can't say how they shift or to work on them. The LT1 T56, AND the ZF6 were both notchy at best shifting.

I had looked into LS1 T56's but I want something to bolt direct to my scattershield. I hate re-buying stuff.

I'd get a TKO, but I've driven them and they shift very sticky. Too much effort for a modern transmission. Saginaw, Muncie, and even the 883 I ran last year shift like butter compared to a TKO!

-- Joe

 

Good thing rotated T5 pattern scatter shields are made. Are we back to the "late model / emissions legal cars don't get raced" mindset again?

The LT1 T56 sprung hub disc / deep regular flywheel is a better option than the solid hub disc / sprung hub dual mass flywheel of the L98/LT1 ZF6 based on availability of parts at this point.

The LS1 hydraulics can be a hassle. Based on line restriction, they don't shift well at high rpm. Drilling that out and a proper bleed on stock hydraulics helps a lot. Look at the volume of posts on hydraulics on tech. I'm not sure I'd go that direction even with aftermarket master / slave and *I* have never had trouble getting a stock master / slave bled and work well on a customer's car.

You can fab a fork ballstud into the LT1 T56 and run a standard push clutch on a 153 (maybe 168) flywheel if you don't mind creating a hole for the fork. Mine is like that using the 78-up A/G-body / 82-83 F-body fork angle but you can also do it with the old straight fork angle or the 84-up third gen hydraulic angled fork / moved ballstud.

You're willing to change powertrain parts umpteen times but then you get hung up on the scattershield. I know it's that one that let's you run a Cripesler box to a Chevy engine...

 

A rotated scatter shield would not work because the shifter would be at the wrong angle, and the rear mount would be angled.

And what are you talking about?

I didn't run a dual mass flywheel on my ZF6. Either way the pull type design is problematic and expensive compared to a normal push clutch. I didn't like it on either of the cars I owned, plus both 6 speeds shifted like crap. The ZF6 had the additional feature of gear noise. The T56 was dead quiet, but shifted notchy and even with the hurst shifter 3rd was a hit or miss.

Oddly enough, the guy I sold the car to ('96 Z28) blew third gear after a year of owning it.

I have not driven an LS1 6 speed car. I have manual linkage in my car, which even with a pretty heavy duty 11" pressure plate (high spring rate) the geometry seems to work quite well with the aftermarket linkage.

I've got the scatter shield dialed into the block centerline. Honestly, it's done. My 4spd works fine too. I'm just thinking down the road. I'd rather have a 'bolt in'.

I'm no fan of the company, and the owner is kind of a jerk. But a 3 year warranty, 600 foot lbs torque rating, and smoother shifts than a TKO (I've been in a lot of TKO cars) sounds pretty good to me.

The best shifting trans I ever ran was a WC-T5 with a hurst pro shifter. I never had a problem making 120mph 1/4 mi passes either, but that was a light thirdgen.

-- Joe

 

Yes, I know. And you know that I know that you know that I know that about the T5 and the RS600.

Your off-angle comment about scattershields didn't make sense.

Not everything can be as cheap as the most common Chevy parts.You didn't run the dual-mass and you outline the ZF6 as noisy? And I ran tyres without balancing them and they vibrated on the highway.

Perhaps you should have fixed third gear in the T56 instead of saying the trans. shifted poorly.
If the McLeod LT1 scattershield fits a 168 wheel, my above quoted suggestion you ignored is an option for you.

As for the RS600 shifting better or being any heavier duty than a T56; If it's indeed T45 based (I don't know for sure but have seen a few T45s,) creative torque ratings won't help it be stronger and nothing about the shift rail setup will make it shift better either.

Hurst Comp Plus on an '88 T5 was a better shifting trans. than any T56 I've driven.

 

Ok. Lets start fresh.

IF you put a straight scattershield in a thirdgen, and run a straight trans it will be fine.

IF you put an angled scattershield, and an angled T5 (tailshaft is angled) it will bolt up.

If you MIX either of the two, the transmission mount will not line up to the cross member. On a T5 the tailshaft is what is 'twisted'.

http://members.cisdi.com/~anesthes/f...nstalled/1.jpg

^^^ T5 on a 'straight' bell housing in my C4.

Right, but even a blue tag ZF6 with a dual mass has some gear noise. And they all shift notchy.

Every gear shifted poorly. Third gear was fine. I'm assuming he missed third and it exploded, like most of the blown up T5's on the forum.

Nothing wrong with your advice at all. But I already bought a scattershield, spent a few hours centering it with adjustable dowels, etc. Again. I have a WORKING setup. I just thought a direct-swap trans would be nice.

Did you read the information from Keisler on what was done? From what I understand, it's a new case, new gears, redesigned reverse, and a bunch of other mods. But loosely based on the T45.

Right. That's my point. I'd like THAT.

-- Joe