4l60e vs. th350 pros and cons

[zooguy]

i had a similar post in the past about going to an old 3 speed trans ... but i am looking to find out from all yall what did you like about each trans and what you didnt like
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example:


pros:
i already have a 4l60e
th350 have been around longer with large after market support

cons:
harder to find some to work on/ build a strong 4l60e
a longer first gear and no over drive.

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can yall help me some?

[dawdaw]

Well you can argue and point out quite a few differences between the 2 transmissions but as you said you lose overdrive and a lock up converter by losing the 60..

The biggest thing for me is I was willing to lose that to have dealings with a LOCAL builder. Turbo 350s and 400s are fairly simple to build and you should have no issue finding a local person to build you one. If you ever have a trans issue , failure etc you can deal with it that day instead of pulling it wrapping it up and shipping it halfway across the country and pay shipping both ways just to deal with someone over the phone and hope it is dealt with in a timely manner.

You won't lose any et at all with a th350 over a 60e.

I guess what it boils down to is

60e: retain over drive and lock up converter
Can slap it in and not have to modify anything
Has to be shipped off to whoever you build it , unless you trust a local guy but whether or not it's reliable is a toss up. Most won't build a performance 60e



Turbo 350:
Locally built
Very strong with a couple minor upgrades
Lose overdrive and lockup converter
Will require a few minor modifications to work.
Cheap to build

tune will have to be written as an m6, different xrossmember , dipstick , also you'll need a new drive shaft unless you put a 9" tail with a 375 out put shaft on it for a 350 )This Is my opinion and just what I think.

[firebird_1995]

It kind of depends what your intended usage is for the car. Do you drive long distances for extended periods? Are you going to make the car daily driver? Weekend warrior? Or strictly a track car?

[shownomercy]

Take your current trans, drive it highway in 3rd, see how you like it.

I like my OD and lock up, 3rd gear lock up in WOT is a damn train smashing into the back of you.

[harner]

I went from a 700r4 to a th350 in my IROC. On the street, I definitely lost a few MPG's on the highway due to losing a gear. I didn't really see much of a performance gain behind the mighty 305. There are plenty of 4th gens that have gone the th350/400 route, though. There's a master 60e builder that is a sponsor on this site, maybe you should reach out to them. ;)

[JPack]

Wouldn't trade my Rossler rmvb th350 for anything. Single best thing I have done. Yes you lose the OD, didn't matter to me. I didn't build my car to be a gas sipper. Lauching off the trans brake at the track is addicting. Only downside with a rmvb trans is no downshift or gonna be a bad story.

[firebird_1995]

I've been hanging onto a 350 turbo with lockup converter for a while. I think that paired with a brake will be my next trans

[CPT]

There have been many good points already mentioned above. Yes, it's true that even a transmission builder with moderate knowledge can build a TH350 for high horsepower. It definitely requires someone with a very good understanding of a 4L60E to get one to hold up to the horsepower, RPMs, and hard launching of a drag car. The TH350 is better suited for a manual valve body as well. The 4L60E will 60 ft harder because of it's lower (3.06) first gear ratio. As a side benefit, that lower first gear also allows the car to launch just as hard as a TH350 But with less stall. Getting the same performance with less stall makes the car much more street friendly. The next big difference is the 4L60Es overdrive. While many discount the loss of overdrive in a drag car as "no big deal", we have many cars that use overdrive in the quarter mile because they're running alot of gear or MPH on the top end. As far as price goes, yes the Th350 is cheaper to have built to handle any kind of drag race abuse, but it's also fair to look at the extra cost of installing a TH350 into a 4TH gen. There are a couple options to get one to work in these cars. The most efficient way is to use a conversion kit. The kit comes with an output shaft that allows the use of the 4L60Es original speedometer. If you don't use the kit there are other options though. You can delete your ABS and use your front ABS sensor to get a signal off the front wheel, you can go full aftermarket speedometer, you can also use the Autometer GPS converter for your factory speedo. The conversion kit has other benefits though. It comes with an aluminum spacer that bolts between the TH350 case and allows the use of the factory 4L60E tail housing. This allows you to leave your torque arm trans mounted if you choose. The other options are to go with a bolt on torque arm bracket, an aftermarket crossmember or body mount arm. The spacer block in the conversion kit also relocates the trans mount in the correct location so it works with the stock crossmember. The conversion kit usually runs around $200 if you can find one anymore. It also requires transmission disassembly to install the output shaft. The kit uses the stock driveshaft as well. As far as strength and reliability go, if a 4L60E is built correctly, it will last just as long as the TH350. If you choose not to go with a manual valve body with a TH350, plan on spending the better part of a day, knocking the governor cover off and pulling the governor out a few times and playing with springs and weights to get your shift points correct. While manual valve bodies can be fun to drive, it's also nice to just be able to set your shift points through the PCM and let a 4L60E shift on it's own.

[CPT]

I've been hanging onto a 350 turbo with lockup converter for a while. I think that paired with a brake will be my next trans

Nobody makes a transbrake valve body for a lock up TH350.

[joelster]

Nobody has mentioned price yet, lol. You can get a nasty th350 for roughly $600-$800, and converters are cheaper too. I hear the street driving argument all the time. Honestly, it's not the "street" part that is different, just the "highway" part. If you want to constantly bomb down the highway at 75mph, then you'll want an overdrive. Just cruising through town at 45mph, you'll be fine with either.

I'd like to see a back-to-back dyno session between the 2 trannies to see just how much more power the 4L60 eats. Maybe Cahall can shed some light on that. I know lock-up converters weigh a ton more than my th350 converters. Reciprocating weight eats hp.

When I first put a th350 in my car I bought a fitz-all kit. It was $150ish iirc. The guys that built my th350 welded a reluctor onto the output shaft so the speedo worked. I had no abs, but I was running skinnies up front anyways. The total cost was around $1500ish iirc. Dipstick, converter, tranny, adapter kit, etc, etc. The whole works. I used the stock shifter, tranny was a forward pattern manual valve body.

[CPT]

I'd like to see a back-to-back dyno session between the 2 trannies to see just how much more power the 4L60 eats. Maybe Cahall can shed some light on that. I know lock-up converters weigh a ton more than my th350 converters. Reciprocating weight eats hp.

When I first put a th350 in my car I bought a fitz-all kit. It was $150ish iirc. The guys that built my th350 welded a reluctor onto the output shaft so the speedo worked. I had no abs, but I was running skinnies up front anyways. The total cost was around $1500ish iirc. Dipstick, converter, tranny, adapter kit, etc, etc. The whole works. I used the stock shifter, tranny was a forward pattern manual valve body.

We've never dynoed the TH350 against the 4L60E, but quarter mile times are about the same. The 2 transmissions are pretty close in overall weight eventhough the 4L60E has a larger outside dimension. The 4L60E uses an aluminum front pump and forward drum though. Both use the same basic planetary set up so I can't see where the 4L60E would eat any more HP than the TH350. I'll have to throw a TH350 on the scale in the shop. I know the 4L60E weighs 125LBS.

The problem with welding the reluctor wheel to the output shaft is that it makes it more of a PITA to take it back apart if you have to. The output shaft/rear ring gear usually pull through the inside on a disassemble. With the ring welded to the shaft, you'd have to pull the snap ring off the rear ring gear with it still in the trans and pull the shaft out the back. I've had those snap rings that are a bitch even with the assembly out of the trans.

A 12" TH 350 and 12" 4L60E converter weigh very close to the same. Same goes for the 9.5" versions of either. The lock up clutch/damper assembly don't add a significant amount of weight. I'll get exact figures on this and report back.

[zooguy]

holy cow guys ... this is EXACTLY waht i was looking for .... thanks to all of the input. most of the time i like to shift my trans even though its an auto ... and i rarely go on long trips (over 30 miles from home) so over drive is rarely ever used. (i actually like the higher rpm sound in 3rd vs. 4th when driving) so that settles it once the 4L60e lets go ill be getting a th350.

now here is where the path leads next .... 3.73's or 4.10's ..... and at the moment i have a 3000 vigilante 10.5" single disk lock up converter .... to keep close to the same road manors i know i would need to go bigger than that ... so ... how big? 3300, 3600, 4000, 4400? and do i change to a 9" converter? i would be okay if it were a little higher stall with the current combo like a 3600. how does that translate to a th350 stall converter?

[CPT]

holy cow guys ... this is EXACTLY waht i was looking for .... thanks to all of the input. most of the time i like to shift my trans even though its an auto ... and i rarely go on long trips (over 30 miles from home) so over drive is rarely ever used. (i actually like the higher rpm sound in 3rd vs. 4th when driving) so that settles it once the 4L60e lets go ill be getting a th350.

now here is where the path leads next .... 3.73's or 4.10's ..... and at the moment i have a 3000 vigilante 10.5" single disk lock up converter .... to keep close to the same road manors i know i would need to go bigger than that ... so ... how big? 3300, 3600, 4000, 4400? and do i change to a 9" converter? i would be okay if it were a little higher stall with the current combo like a 3600. how does that translate to a th350 stall converter?

If you go with 4.10s, you're going to need O/D in the quarter mile unless you have a high PRM cam that makes power above 6000 RPMs.

Your converter stall will be dependent on the cam duration, vehicle weight, rear gears, horsepower, and of it's a power adder car.

Frank

[joelster]

Pick the ET that you will be happy about running and then you'll know what mph you need your car to hit when it crosses the stripe. Gear it accordingly. For example, if you ultimately want to run mid 10's, then you'll need it to cross the line at around 127-128mph. Figure out what rpm your engine can safely rev to, then plug in the tire size and gearing into one of those calculators. Keep in mind that there will be some slippage with a th350 converter. If your engine is all done by 6000rpm and you plug in some 4.10's, then your car will top out way before you reach your ET/mph goal, and you'll have to change everything again.

[KLaBZ28]

Take your current trans, drive it highway in 3rd, see how you like it.

I like my OD and lock up, 3rd gear lock up in WOT is a damn train smashing into the back of you.

I need to know more about this. I set no lockup in 3rd., car always feels like it falls on its face after 2nd, but thats probably more of a stock lt1 with bolt ons problem.

[shownomercy]

Usually you cannot/shouldn't lock up converters at WOT.

[KLaBZ28]

right. so im curious why you have lockup in 3rd wot.

[shownomercy]

I have a triple disk converter rated at 1000hp

[KLaBZ28]

Cool that's like diesel shit.. what brand?

[shownomercy]

FTI

[SexyTransAm]

i lock mine up in 3rd as well. the car loves it

[KLaBZ28]

FTI

slickkk

I have a yank ss3600. Do you think I'd benefit from a lockup in 3rd? Its going on the bottle soon..

[shownomercy]

If you have the power, it couldn't hurt.

But, that assumes your trans is built for it and or your 'verter clutches can handle it.

[KLaBZ28]

I'm still running a stock 4l60e :(

[gmpowered]

i lock mine up in 3rd as well. the car loves it

Still running the revmax?

[SexyTransAm]

sure am.

[gmpowered]

I used to lock my old edge converter with good luck. I've been worried to lock my revmax converter.
I have the same basic setup you did before your newer cam, only a 3600 revmax
I'll have to try it. I know its good for mph.

[dawdaw]

FTI

They build junk converters! :)

[JPack]

Dawdaw you are funny haha..... I gots me one of them FTI converters too.... bad mofo!

[dawdaw]

Oh yeah mine seems to work ok so far! Haven't got to spray mine yet.

Mines an 8" mechanical diode aluminum stator snowman.


Yours seems to get down on the spray!

[KLaBZ28]

I'll have to try lockup in 3rd. The car needs something for the 3rd gear pull. 1.68 60' and trapping 107.

[shownomercy]

I would data log your slip in WOT first. If its not terrible, what do you expect to gain other than wear/tear on your clutch material.

[KLaBZ28]

Yeah probably not a good idea. I just feel like there's something left in it as far as trans tuning. I'll just have to spend some time tuning and read more.

[shownomercy]

Also, remember you are on a stock 60e, so good knows how its life signs are etc. Could just be slipping at WOT and on its way out.

Blindly changing things solves nada.

[KLaBZ28]

Yup. I was thinking about sending it to be built. But I have a whole T56 donor car sitting in my yard that I can't decide if I want to go slower and swap it..

[BIG CAT]

whats the intended power? with a 4l60 the first gear is a fair bit lower than the th350 so if your going to be running single digits and faster the th350 first gear will be much easier to launch and be consistent with. also guys i cannot stress enough how important the trq converter is to making the car run to its full potential.