[JLMounce]

After a couple years of saving, hording parts and research, I finally sent my Firebird off to the shop to handle a transmission swap to the 4l60e I had built.

Typically I try to handle most everything myself, but having just moved and not really ironed out the garage, along without a lift, I felt it prudent to have a professional handle the install.

This morning I got a no-go from the shop.

In all of the research I've done this has never come up and honestly it didn't even cross my mind.

The later model 4l60e trans have a modular bolt-on bellhousing that is designed for an LS engine. It's a completely enclosed housing with a knockout for the starter. A starter that...is on the passenger side of the engine.

I'm really just putting this here to vent a little, but also hopefully the searchable nature of the forum, it can help people out.

There is an option from QuickTime that will make this work. It's not cheap at about a grand. In my situation that bellhousing didn't completely solve the problem because I had my torque converter built specific to the build, which means the pilot had already been lengthened. Going to the quicktime unit, I would have also had to install a mid plate to take up that extra length from the converter pilot.

This of course is all happening as the car is occupying a bay and lift at a shop.

My initial thought was to get the bellhousing and send the converter in for alteration, but with the car already at the shop, instead of just stabbing the trans back in and paying whatever labor I had already accrued, I simply decided not to re-engineer the wheel here. I'm having TSP build me a new converter for my th400 and I'm putting a more highway friendly gear in the back.

So yeah, 96+ 4l60e's with bolt on bellhousings will require an aftermarket bellhousing to work with a BOP engine. Unless you want to get frisky and start cutting up the bellhousing.

Considering the parts are basically interchangeable between the 4l60e and 700r4, unless you absolutely need or want WOT lockup in forward gears, you're much better off doing the conversion with the 700r4. Of bypass this series of trans and use a 4l80e, which is what I really should have done to begin with, but got talked out of by my transmission builder.

So expensive lesson on this one. I'm hopeful the addition of a proper converter, replacing the hold B&M Holeshot 2000 and a taller gear out back will be a good and reliable compromise on performance and highway usability.

The converter will be one of TSP's tight 9.5" units and I'm dropping from a 3.73 down to a 3.31.

[Scott65]

Sorry to hear of your troubles. I bet the new gear and converter combo will work well though.

[JLMounce]

Originally Posted by Scott65

Sorry to hear of your troubles. I bet the new gear and converter combo will work well though.

I'm hopeful that will be the case and I can just get back to enjoying it.

I never had issues with the trans, nor the torque converter. It was always just a bit taxing on the driver heading down the interstate at 65 mph turning 3400 rpm.

The converter was always a bit too tight though, having a properly spec'd unit for my engine combination will probably wake up performance beyond what I may be losing by adding taller gears.

[Scott65]

I like my 3.31 gears with my switch pitch. It cruises at the legal speed limit nicely.

[Formulajones]

I use 3.31's in the bird with it's 400 turbo and a GM L88 converter. I drive it everywhere, and it's fine on the highway. Doing a 200 mile trip tomorrow.

Sorry to hear about the 4L60 deal. Kind of surprised a transmission guy talked you out of a 4L80E though and into a 4L60??

[pastry_chef]

Every year on here there are three or four heated overdrive threads. I just searched for 4l60 , those names that often recommended it. Damn.
Why I listen to very very few in this world!

[Half-Inch Stud]

Can you whack the 4l60 bell ousing off and buy a bellhousing?

Meanwhile, I bet you will be happy with the Th400 back in. I suggest you go 3.08:1 or 2.73:1 if you have a healthy 455, and a tight converter for best highway enjoyment. Many aftermarket converters get mushy with highway gears.

[Schurkey]

Originally Posted by JLMounce

So yeah, 96+ 4l60e's with bolt on bellhousings will require an aftermarket bellhousing to work with a BOP engine. .

Not exactly.

Buick has the starter on the same side as a Chevy--same starter, in fact, as the Chevy with the smaller flywheel.

Pontiac, Olds, and Caddy (except Eldorado) have the starter on the left side.

[JLMounce]

Originally Posted by Formulajones

I use 3.31's in the bird with it's 400 turbo and a GM L88 converter. I drive it everywhere, and it's fine on the highway. Doing a 200 mile trip tomorrow.

Sorry to hear about the 4L60 deal. Kind of surprised a transmission guy talked you out of a 4L80E though and into a 4L60??

Kind of a long story. He was selling an overhauled 80 that I wanted. Withdrew money and got halfway there and he sold it to somebody else. I think he felt bad about it, so he maid me an offer to build me another trans at the price I was going to give for the 80.

The argument for building a 600hp capable 60 is fairly strong in a lot of ways. More aggressive gearing, lighter weight, quicker shifts etc. And honestly if you know about this issue ahead of time, it doesn't become as big of an issue as it turned out to be for me.

Originally Posted by Half-Inch Stud

Can you whack the 4l60 bell ousing off and buy a bellhousing?

Meanwhile, I bet you will be happy with the Th400 back in. I suggest you go 3.08:1 or 2.73:1 if you have a healthy 455, and a tight converter for best highway enjoyment. Many aftermarket converters get mushy with highway gears.

There are aftermarket bells that can solve this. My issue was mainly the custom converter that would have to be sent back, the time and sunk cost of paying somebody to basically take out my th400 and simply put it back in.

I considered going down to a 3.08 which is the tallest gear my carrier will handle, but this is still primarily an around the town performance street car. staying slightly higher with a 3.31, I also allow myself room to go to an 80 later on if this change doesn't really meet my needs.

[JLMounce]

Originally Posted by Schurkey

Not exactly.

Buick has the starter on the same side as a Chevy--same starter, in fact, as the Chevy with the smaller flywheel.

Pontiac, Olds, and Caddy (except Eldorado) have the starter on the left side.

You learn something new every day. I was under the impression all BOP had left side starters.

[Skip Fix]

Maybe a Sawsall on the driver's side

[72projectbird]

I'd just cut the bell housing.


But... I'd rather use a 4L80E

[Kirill Catalina]

Hey Jason,

What a shame.. But i was wondering, (since i have a 4L80e waiting to go on my 73' 400 Pontiac and i dont want to end up like you did) you say you should've got the 4l80 instead of the 4l60. My starter is also on the drivers side. Does the 4L80 fit with a left starter unlike the 4l60?

[67Fbird]

well that just SUXS.....sounds like MY WORLD.!!! Hopefully not a BIG $$$$ killer but still sux.

[RocktimusPryme]

That sucks man.

Just from an informational perspective. Im curious what your trans guy liked better about the 60E than the 80E? Just availability? Im sure they made a ton more of them.

[67Fbird]

probably the 3:1 first gear...and 50 lbs lighter..

[Sirrotica]

Originally Posted by Kirill Catalina

Hey Jason,

What a shame.. But i was wondering, (since i have a 4L80e waiting to go on my 73' 400 Pontiac and i dont want to end up like you did) you say you should've got the 4l80 instead of the 4l60. My starter is also on the drivers side. Does the 4L80 fit with a left starter unlike the 4l60?

Yes, the 4L80E fits with a traditional Stratostreak V8 engine with just an adapter plate to go from chevy bell pattern, to BOP pattern. You can rest easy that it will all bolt together.

Here is a detailed thread of putting a 4L80E in a 68 GTO:

http://forums.maxperformanceinc.com/...d.php?t=823023

[JLMounce]

Originally Posted by RocktimusPryme

That sucks man.

Just from an informational perspective. Im curious what your trans guy liked better about the 60E than the 80E? Just availability? Im sure they made a ton more of them.

From a technical standpoint the 4l60e is a better "performance" application, assuming it's built to handle the power. It's gear ratios, especially with the 6 pinion planet are better.

It's designed as a car transmission where the 4l80 is a heavy duty "truck" transmission. That was his main argument.

The 60 will go behind a BOP, you just have to go aftermarket bell, which really increases the price.

[Formulajones]

I'm more of an 80 fan than a 60 fan. I've run the 4L60E's in performance applications but never really liked the 3.06 first gear dropping to a 1.62 second if you had a really tight converter in it. Better with a loose converter but the 3.06 first gear still really isn't necessary.

So I just prefer the 80 gear ratios more, and the overall beef of the trans that will take more abuse than a street car will throw at it and it really doesn't need a bunch of modifications to do it. Most reputable places that build the 80's are relatively stock internally, no fancy billet input shafts, or output shafts, no fancy drums or sprags, and they'll still warranty them up to 850hp. Just a simple billet input shaft is all that is changed to push that warranty up to 1000 HP and Steve at Hughes has told me they have dozens of them running the stock input shaft at those levels without a problem, even though they do recommend a billet piece for those HP levels.

[JLMounce]

Originally Posted by Formulajones

I'm more of an 80 fan than a 60 fan. I've run the 4L60E's in performance applications but never really liked the 3.06 first gear dropping to a 1.62 second if you had a really tight converter in it. Better with a loose converter but the 3.06 first gear still really isn't necessary.

So I just prefer the 80 gear ratios more, and the overall beef of the trans that will take more abuse than a street car will throw at it and it really doesn't need a bunch of modifications to do it. Most reputable places that build the 80's are relatively stock internally, no fancy billet input shafts, or output shafts, no fancy drums or sprags, and they'll still warranty them up to 850hp. Just a simple billet input shaft is all that is changed to push that warranty up to 1000 HP and Steve at Hughes has told me they have dozens of them running the stock input shaft at those levels without a problem, even though they do recommend a billet piece for those HP levels.

Agreed, the factory gear ratio drop from 1st to 2nd is pretty suck. However going to the 6 pinion planet changes the ratios. You end up with 2.84, 1.55, 1:0.