JKTURBOTA

Anyone have any experience running a Century or Circle D built 6l80e? Weighing my options and wanted to know which company you prefer and why?

realcanuk

I'm pretty sure they are both more than capable. Seen good and bad experiences from both, but from my 6L80 experiences I would bet it comes down to the tune.

TripleBlackZ06

I had Circle D rebuild my 6l80 5 years ago & 2500 stall speed & still holding up with no problems

usmcpony

I made the decision between the two a couple years back. As soon as circle d told me they don't warranty their work. I went with century. Had my trans back in four days and Mike will email you tunes everytime he makes improvements. Made 780rwhp and still holds strong. I'll be making over 1000rwhp so I'll definitely be testing its durability.

JKTURBOTA

what power level are you at?

JKTURBOTA

ya i saw where Circle D has only a 6 month warranty to Century's 1 year warranty. You think you would have more confidence in your product to warranty it more than 6 months.

realcanuk

Surprising they warranty it at all considering it is so dependent on the tune and most how buy them abuse them heavily at the track.

CI GS

No kidding. Especially when they're two out of only a handful of companies that will even touch the 6L80s nowadays.
And if you think offering a built transmission without a warranty is bad, those of us who have dabbled in the boat racing business are familiar with the likes of Mercury Racing selling brand new $75,000+ motors without a second of warranty on them.

usmcpony

Century tunes their own transmissions. If a shop tunes it. I believe it voids the warranty. Circle D wouldn't warranty their trans or tune at all when I was searching.

realcanuk

I dunno. I just did mine locally, choosing all the upgrades myself from research. Cost half the money. Might have gone with Century if it wasn't so far for me. Having a warranty is no good if my car has to be down for a month to use it.

usmcpony

I only sent it out mostly to get the 300m shaft, the modified valve body and the tune. I'll be doing the clutches myself or locally once they start to fail.

bmfvette

Agreed, I put a Sonnax boost valve kit, Circle D stall, and a trans cooler w/fan and letting it roll until it breaks. It's all about the tune..

realcanuk

I did a bit more than that. Most stuff that the mentioned builders would do. It's held up fantastically so far.

JKTURBOTA

Thanks for all the input guys!

bmfvette

Ya, I prolly should have at least welded the baskets while I had the pump out. You stay with the stock clutches?

realcanuk

Yes. Welding them a good idea. I stayed with stock clutches with a few extra added to the 4,5,6 pack.

barneygookle382

Need to pm Subfloor

realcanuk

I do ? Not sure what you're saying. I spoke to Subfloor (Christopher) many times. My trans has been done for 3 or 4 years with between 750 and 1000 rwhp and is working just fine.

bmfvette

I've read a lot of material since I had my transmission apart that I should of read while I had it apart.

One was adding an extra stock clutch plate to the packs instead of changing to different friction clutches. You only aded to the 456 pack and you added more than one?

Next time my tranny is out of the car, I'll be doing a few of these mods.

realcanuk

If I remember it's just one there. I will look for my notes later and double check. Memory goes with age !!
Aside from that it's billet intermediate shaft, weld drums, wide mouth filter, and all the sonnax upgrades available.
Also if it's an 07 (not sure about 08) the front pump should be changed for the updated one.