You know my choice, 400 all the way.

There were a lot of 400 failures at KOH this year. I'd be interested to see what happened to them. The new Reid case solves every issue you can think of, but its obviously not cheap.

Keep it simple.

 

I know you like the 400. I talked to the guys from Reid out there and got to handle the case. They had a ton of great information about it, and it's a solid piece for sure. Just out of my budget.

What were the problems your friends had with their TH400s? These two trannys are basicly the same, most parts are interchangeable but the 4l80 is def. stronger. No a 4l80 will not last long behind a 500HP motor in stock form it will need some mods.

One trans lost reverse as it got into the rock section on the 2nd lap, then lost 3rd towards the end of that lap (edit: see above post by 87jeepwrangler). The other had no 2nd gear from the beginning. Both had stock Gen III 6.0's.

Miller has always had trans problems except for this year, but his trans costs almost as much as my whole build probably will (Culhane).

 

What were the problems your friends had with their TH400s? These two trannys are basicly the same, most parts are interchangeable but the 4l80 is def. stronger. No a 4l80 will not last long behind a 500HP motor in stock form it will need some mods.

 

we can't keep a th400 together. we've had 3 different trans failures in just a handful of races with this car. first one we blew the case and 2nd gear case lugs apart. now we run a case saver, but constantly have other troubles. lost reverse during KOH this year, and thus only had time to complete 2 laps.

never had a problem with a th350 in all the years of racing one in the old car.

 

One more data point is that Lucas said he is considering going to a th400 from a 4l60 (or 80 whatever he has now) because he's had several case failures. I assume the 4l80 doesn't have an aftermarket case like the th400. I think he plans to run the Reid case if he switches.

I know the Reid case is very expensive but it's also an investment in not having to get transmissions replaced in the future and not losing races or rec wheeling weekends over it. Is the free th400 an HD case?

I know you are looking for simplicity, but I'll throw this out there. Brian Shirley is still running the same stock 6l80 that he raced in KOH last year and has now raced a dozen races on the same trans. Levi swapped in a fresh 6l80 in his because the first one always ran hot but never lost any gears. The first one had 8-10 races on it and the new one has a couple as well.

Unfortunately you need an engine/ecm that's compatible with the 6l80 and your year 6.0 probably isn't. Several companies make a kit to convert a 24x reluctor ring LS style engine to a 58x setup that is compatible with the 6L80.

Good luck with your new build!

 

I know you are looking for simplicity, but I'll throw this out there. Brian Shirley is still running the same stock 6l80 that he raced in KOH last year and has now raced a dozen races on the same trans. Levi swapped in a fresh 6l80 in his because the first one always ran hot but never lost any gears. The first one had 8-10 races on it and the new one has a couple as well.

Unfortunately you need an engine/ecm that's compatible with the 6l80 and your year 6.0 probably isn't. Several companies make a kit to convert a 24x reluctor ring LS style engine to a 58x setup that is compatible with the 6L80.

Good luck with your new build!

The 6l90 would work but it has a non standard output. So figure that into it as you need a input adapter as well. The 6l80e is 32 spline as mentioned.

I have seen several high HP vettes and 5th Gen F-bodies eat even built Circle D 6l80e. But they are on drag slicks. And hooking well. So I am sure that why they were failing.


There is no standalone setup for the 6lxx so far lots of talk but nothing, for a Gen III PCM for carb motor. There is only a 58x to 24x box it doesn't go the other way as far as electronics so that is not an option unless you have found something else. So you have to run the Gen IV ECM and be 58x to run a 6lxx.

The 90 is little longer and has larger internals than the 80 but has a different output.

 

Strength is negligible between the two, do you want OD or not?

The only time I can think of a th400 ending a race in millers car was when the driveshaft got taken out and broke the back of the trans off.
At the badlands last summer we had the trans so hot that the fluid was literally black and smelled like sewage when we drained it(we still finished top ten). Most of the other problems were either wear items not getting replaced during "rebuilds", bad torque converters, broken inputs/sprags, or shifter cables being out of adjustment, etc.
The culhane trans still gets pulled and gone through every few races, but it has been flawless so far. We probably spent two to three times the initial build cost of the culhane in the first half of last year dealing with poorly built transmissions.

 

Running compression braking is a big problem in its self. It doesn't hold up to hard down shifts and will chew its self up.

I'm going to run a 4l80e in my new rig but its going to see street use so over drive is a must.

 

Sounds like you are decided against a 6l80 but with an 08 6.0L and e38 ecm then your engine/ecm is compatible with the 6l80 so that is another option.

 

The main reason I'm shying away from the 6L80 is the packaging vs. the 400 or the 4L80.

What would I need to do in order to run a 6L80E with my PCM and harness?

 

TH400. Cheap, simple and easy to build. Assuming no catastrophic failures, you could rebuild one on the lake bed easily. There ARE a few things to know though.

Cases are weak. Gotta mount the t-case WELL taking into account the leverage the front output has on it. Stock cases have held up on extremely fast drag cars for years. Mine came out of my drag car which dead hooked 1.27 60's in 3500 lb car that ran 8.70s. They just don't like being slammed around on mounts with excessive play or the t-case wrenching on the output flange.

RMVBs without engine braking. They DO NOT handle 3-2 downshifts well. No intermediate band to match the input/output. Essentially a 3-2 downshift unloads the sprag, when you hammer the throttle without the sprag loaded, it's the equivalent of a neutral drop. Feels good and powerful until it pops. Just gotta be mindful and roll into the throttle easier when going 3-2.

 

RMVBs without engine braking. They DO NOT handle 3-2 downshifts well.

I run the ATI RMVB and rebuild kit without engine braking. The tech at ATI told me that engine braking was a weak point in the TH400. I was worried that I wouldn't be happy without it but I like it just fine.

Summit Racing had a cheap price on the kit with VB but I had to get the part number from ATI.

 

The 6L80 is certainly bigger around. Swapping to the G8 pan and filter for around $70 helps that. The clutches are also considerably bigger I'd say. It is also 7/8ths of an inch longer than a th400. not sure compared to the 4l series.

Does your harness already have a 3-4 foot long pigtail that ends in this connector? it would be on the same loom as the passenger o2 sensor(s) Hopefully it wasn't cut off.
EFI Connection, LLC - Connector Details

If so then wiring wise you most likely don't have to do anything. If you have EFI live or someone can check your ECM and its set for an auto transmission then you are set there as well. then the only thing is if you want to do tap shifting there is some tuning to do in the transmission. This video is of Drew Burroughs in a 2010 6.0L engine and a stock 6l80 with no tuning on Backdoor.

Drew taking Ryan for a spin in the new Ibex buggy running a - YouTube

 

Thanks for the info Dave. Very helpful.

Yes, my harness has that connector on the end by the O2 plugs.. None of the wires were cut. Cotous Truck Country in Willmantic did a fantastic job removing this engine from the truck very carefully and including whatever I may or may not need.

As I mentioned, the truck was an automatic but not a 6L80. Does this matter from a tuning standpoint?

 

Chris, Jake Burk had a 6L80 he was trying to get rid of a while back. Not sure if he still has it, but you might see what he wants for it. The 6L80 is bigger, but I think it's better packaged. Most of the mass is below the centerline, and the pan/body is fairly symmetrical which makes it possible to run a passenger side front driveline should you choose to do so.

The 6L80 also has a 4:1 first gear and 2 overdrives which opens the doors for quite a wide range of gearing options both in the axles and the T-case.

 

I got Jake's 6L80. I do have a 6L80 spare still that I went through and put low mileage clutches in.

Chris you mentioned your truck was 2wd with a 6L90e in it. the 6L90e so far as I know has the same T43 transmission computer (TCM) as a 6l80 so I don't think that will be an issue. There is a sticker on your ECM that should list the operating system. I can probably get more info from there without even scanning it. The ECM just needs to send RPM and load info to the TCM so I don't think the e38 cares between the 90e and the 80e.

I don't want to sound pushy because the simplicity of a th400 is also compelling but the durability of a stock 6L80 is starting to get proven and if you have to build a th400 I think the price of a 6L80 starts to get compelling. you can also bolt an Atlas to a 6L80 without an adapter which saves money. If you already own the Atlas and don't buy it with the 6L80 clocked 6 bolt pattern then you need to redo the atlas clocking to get it to work or buy the 6l80 tailhousing from AA. AA sells Atlases specifically set to work with the 6L80 now also. the bolt pattern is the same just the clocking is different.

 

I got Jake's 6L80. I do have a 6L80 spare still that I went through and put low mileage clutches in.

Chris you mentioned your truck was 2wd with a 6L90e in it. the 6L90e so far as I know has the same T43 transmission computer (TCM) as a 6l80 so I don't think that will be an issue. There is a sticker on your ECM that should list the operating system. I can probably get more info from there without even scanning it. The ECM just needs to send RPM and load info to the TCM so I don't think the e38 cares between the 90e and the 80e.

I have to swing by the garage tonight anyway so I'll get a picture of that sticker on the ECM.

I don't want to sound pushy because the simplicity of a th400 is also compelling but the durability of a stock 6L80 is starting to get proven and if you have to build a th400 I think the price of a 6L80 starts to get compelling. you can also bolt an Atlas to a 6L80 without an adapter which saves money. If you already own the Atlas and don't buy it with the 6L80 clocked 6 bolt pattern then you need to redo the atlas clocking to get it to work or buy the 6l80 tailhousing from AA. AA sells Atlases specifically set to work with the 6L80 now also. the bolt pattern is the same just the clocking is different.

Not taken that way! I'm simply exploring options right now. The more I'm learning about this trans, the more I want to know. A TH400 is simple but that does me no good if I have to spend money to build it just to have the luck that Tim Smoluk has had with his this season. If Shirley's are running 6L80's stock with those results, it may be worth it to run one, especially with that deep first gear and two overdrives.

I have an Atlas that I ordered for a TH400. Do I just need a different clocking ring, or is there more to it than that? Are the output splines the same on the 6L80?

 

Subscribed. Since this thread has turned into a thread about the 6L80 I figured I'd mention something I found out when doing research on this trans. There is a thread on ls1truck.com talking about this trans and people have said that using the '08-up Malibu console shifter will give you the ability to use manual shift mode with the 6L80. A shop in Vegas swapped a L92/6L80 into a JK Wrangler and they used the Malibu console shifter with it. They also used a stock driver side drop Chevy NP241 with SYE in that rig and said the 4:1 first gear combined with the stock low range in the transfer case and axle gearing works well for what they use the rig for.

Scott

 

Is there an official 6L80 thread? Searched, found a couple odds and ends.

We want to go 6L80 in the IFS Goat Built, but def need to learn more.

 

No official thread that I know of.... I own two stockers and they are affordable if you have time to shop around. the internals are substantial and they are designed stock to handle towing and 400+ hp/torque so I consider that a step in the right direction. It seems when I first started googling them I read they were being "built" to handle substantial RWHP in the pavement world... 800-1000?

I think the L92 is quite similar (from a GM site) but a hair longer and with an odd spline output shaft. Maybe a 6l80E shaft could be swapped in, IDK.

I hope to have seat time with one in a couple months

 

6L85E Specs, Info, How it Works

Here is the thread I talked about earlier. Has a bunch of useful info about the 6L80.

Scott

 

Its actually the opposite. The engine braking is caused by the intermediate band slowing the drum down so that the input matches the output speeds at which point the sprag will lock. With RMVB without engine braking the intermediate is removed. So when you shift from 3rd to 2nd the drum just keeps spinning at output speed, yet the input can drop WAY down. Sprag remains unlocked. Then you nail the throttle from whatever speed input is at and it revs virtually unloaded until it hits the speed the output is at... Sprag locks and 1 of 2 scenarios... You get a kick ass "I need to start roll racing my buggy for $" feeling... Or the drum explodes and comes through the floor. LOL.

He WAS right in a sense because the intermediate tends to break on TH400s.

 

... Or the drum explodes and comes through the floor. LOL.

Crap, that is good to know.

 

Does a TH350 not have the same issues with engine braking as a TH400?

Is the engine braking separate from the valve body pattern or does the fact that it's reverse have anything to do with it?

I don't know anything about these damn things, I'm building a stick shift racer still. :laughing:

 

Are all the case failures from internal parts failing or because of the strains of chassis/suspension/transfercase? There's drag guys putting down like 1000+ hp on big slicks that never complain about the factory case.

Are people putting them together in their garage or are these like reputable (hughes TCI culhane rancho) racing trans? There's more to assembly in a race trans than heavy clutches and bands and following a haynes manual.

As for the 4L80e compushift pretty much writes the book on getting them to work on non oem computers. I worked with a guy who had a daily driven blown avalanche with 800hp at the tire who was running a 4l85e and dumped the oem trans code when it got tuned because the oem computer wasn't "fast enough" and did some weird stuff, irregular shifting, missing shifts hunting for gears, etc. He did valve body and servos and knew he was going to eat the factory trans and had it rebuilt and didn't have a problem since.

 

IMO, it's the bouncing across the desert that is killing the transmissions (and all the other parts). The drag guys hit the go and hold the load to the end, the wind up and torque is immense, but there isn't the massive repetitive shock load that the U4 guys are seeing.

 

And most TH400 race apps are not doing the 3-2 downshift said to be a major concern in this thread.

Has me wondering if the computer controlled tranny though likely "softer" in shifts may live for that very reason. between soft and alignment of teeth etc.... Need some bonafide tranny guru's to chime in.

 

Here's a response on yellowbullet from a very well respected builder (Hutch of Hutch Transmission) that has transmissions in some extremely high HP cars. The topic was downshifting an RMVB TH400 then chopping the throttle.

Here's the deal guy. The rmvb was made for competition use and requires load to be applied constantly during a pass. It seems fun to downshift , let me motor come to an idle then whack the throttle and feel the smash of the windup of stored energy hit the sprag and accel the car until the ****ing trans comes through the floor (you beter have a shield on this bastard).

Im old and of course I have done all this stupid shit so I guess what im saying here makes me a hypocrit . Stop doing it before you smash your shit and hurt someone. I said this nicely in an earlier post. Downshifting is not the problem , its how you accel after the shifter is downshifted that matters. What does not matter is what gear we downshift to, as the same principle applies.

 

Thanks for that gem, makes a lot of sense now with the RMVBs that are coming apart.

We had a huge learning curve when we went from trail riding to rock crawling, then to rock racing and now onto this U4 nonsense where every little part rattles loose, shakes apart and any little flaw in your system is going to rear it's ugly head and just when we think we are starting to figure it out, along comes this IFS fad (see what I did there... ) which makes these cars even easier to overdrive them.

We are only at the tip of this iceberg and we'll be finding out and figuring out a lot more in the future.

 

Thanks for that gem, makes a lot of sense now with the RMVBs that are coming apart.

Any reason that doesn't apply to FMVB when downshifting as well?

 

No problem Tim.

The good news is that the fix is pretty easy on a tranny without engine braking. Just buy a VB WITH engine braking, replace the servo seals that they omit from the non-engine braking build and throw a intermediate band back in. (Essentially return it to the stock configuration with the new VB.

I'd wager that there are more non-engine braking TH400s in service in rock crawlers than any other MVB type. Most get away with it because they're not hot lapping. I'm not an expert by any means, but I simply don't see how a non-engine braking TH400 could survive long in any racing environment that requires downshifting. Upgrading drums and sprags can help lessen the failures, but the internals take just as much of a beating.

 

Maybe a non-engine braking, forward pattern, automatic valvebody would be the solution for the guys that keep blowing up TH400s?

 

I know I'm right as we just pulled the pan off of a Hughes TH400 that had less than 50 miles on it and it had a ton of clutch material in the pan! It can't disengage the 2nd gear band and temporarily locks up the the tranny. There is no good way to fix this problem.

 

I wish they didn't call it engine braking. LOL. Manual transmissions and exhaust brakes are for "engine braking". I use the brakes to slow down and the transmission to run. It's much easier to brake, select gear and hammer down than baby the sprag on downshifts with the throttle. This is the scenario where a manual "engine braking" set up works. Maybe they should call it a "Manual Valve Body with Downshift Matching and Synchronization". :laughing: