Trouble with trannys...Is that okay to say?

It finally happened to me after nearly a dozen B-Bodies, I finally caught the dead tranny curse that plagues us all. I have a deal to get one from Tom, (Won't be caught without a back up again) but in planning for the future I ordered a custom build from Monster Transmissions. We have all seen them used on our favorite builder shows, they trust them, why shouldn't I? I mentioned this on Facebook, and was almost immediately told I should cancel this order. Followed with numerous horror stories of their work. What have you guys heard? I feel like I am getting conflicting reports...Would appreciate some feedback. Thanks in advance...

A good local trans builder can put one together for you, and you probably will not have to pay for shipping. You tell him what you want to do with it, make it as heavy duty as you want. I had a custom trans built for my 454 install. If you supply the core (local P-N-P junk yard about $125-170), it should be about $1400-1500, and a $500 custom 2400 rpm stall torque converter from Circle D (special deal on right now) will handle anything your LT1 can throw at it. I installed it myself, and saved a few hundred dollars (I put the engine and trans in as a unit). It is actually easier to pull both, and separate them outside of the car, then join the new trans to the engine, and install it as a unit. You are still a young guy, and should be able to do it single handed. I swapped an engine last March by myself, and I am over 70.

When removing the engine/trans unit, cap the back of the trans or you will have an ocean of trans fluid under the car.

Apparently, I havent met the right type of builder. I discussed my idea with our local builder and he wanted no part of that. Outside of his comfort zone...

Where I am, there aren't really many locals left, and the few I've spoken to would take the job to rebuild a 4L60E but they freely told me that a rebuild job they do themselves costs more and would have a shorter warranty period than getting a rebuilt unit from an outside rebuilding firm (Like Jasper or whatever)

I ended up getting a reman unit from Rock Auto, got a couple of friends over, and swapped it out myself. It's been fine so far.

By the way the local guys will build race transmissions no problem, but of course the parts/expertise there means higher margins and racing pretty much means no guarantees anyway.

You should have a "Beast" shell, and heavy duty clutches. The Beast shell is one of the important pieces used to keep the trans from letting go of 3rd & 4th gears.

I appreciate the input guys. Not sure race is the right word for what I am looking for. Beefed up for sure, must be able to handle the future hp levels, but it will not be beaten on like a dedicated race unit. If Cadillac can have a 500hp daily driver, than dammit I want one to! Just in a Caprice wagon body, just like God intended.

If you are putting 500 HP in a car, the trans is essentially a race build. If you have a higher rpm stall converter, it will make it act a lot nicer on the street. The sloppy TC will make the shifts smooth, until you hit the lockup. At that point, it will be harsh, and fast. I run a 2500 RPM stall converter with my 454, and under "normal" driving conditions, it is smoother than my stock trans with stock converter on my stock 350. Hit the stall of the converter, and it is a hard shifting bear.

I stay away from Monster transmissions - they have a great media presence; that's about all I can say.

I would recommend a Jasper or a shop that one of the F-body groups recommends. Out of four Jasper transmissions I've dealt with, only one had a problem, and all things considered it turned out very well with minimal impact to our trip (of course they fail when you're 400 miles from home!).  I do not know if Jasper offers performance 4L60Es but they certainly could build them. Give them a call.

I continue to NOT be impressed with local shop 4L60E rebuilds. From what I see, they replace stuff they've personally had problems with and then don't bother reading up on what else could go wrong. Make sure they actually check the valvebody for leaks using the Sonnax test plates.  

Also, the 3-4 clutchpack problem has been solved. If the local shop doesn't like you bringing up this article, leave.  The 74140 HD 3-4 backing plates are well worth the $100, and allow you to run the newer 7-disc 3-4 clutch setup. Also, if they don't recommend the '97-up stamped steel input pistons, leave. Same with Sonnax boost valve and the Sonnax pinless accumulator pistons.

Definitely use this build guide, and you can price out accordingly.  For prices, as a parts ballpark, I spent around $800 for a stock rebuild good to 375HP, and around $1800 for a Sonnax Level 2.5 build (added the Smart Tech input drum but left off the hardened input and output shafts as they would have added another $800 and I agreed never to put slicks on the car).  This include sending the pumps and valvebodies out for refurbishment and fixing leaking input drums where the shaft presses in.

For TCC in the '95-96 cars, ONLY use the Sonnax 77754-04K or 77754-03K (for smaller diameter torque converters).  None of the other fixes I've seen properly restore TCC operation.  Read more here.  If a shop tells you any other way, leave.

Regarding a comment above, the Beast sunshell is old tech at this point, heavy, unbalanced, and does not address the overloaded captive rear bearing, which the Sonnax Smart Shell does.

If you are still reading... one possibility is to buy a reman unit and then as soon as the warranty is up, open it up and put upgraded hard parts in it (sunshell, new 3-4 clutchpack, wide 2-4 band, and upgraded servos). Drop the valvebody and clean the screens, replace the accumulator pistons with the Sonnax ones, check the boost valve and put a Sonnax one in it while you're in there, and then put it back together. All of this you can do with regular tools.

How many miles/years did you get from the original?

GMs transmission-in-a-can program is good enough if you are not using nitrous or towing a 6000 lb trailer.

I had mine built locally for the specific application. Other than one miscommunication, the trans is great. I have about 5K on it at this point. The guys who build them here have been doing it for a good while. They build racing transmission as well. The shop is Just Rite Transmissions, in Clearwater Florida. https://www.facebook.com/Just-Rite-Transmissions-289334411403521/

I appreciate all the continued info. Jasper was the first call I made. No dice. Locals next. 2 nopes. Summit, Jegs, and finally Monster. Sherlock I will experiment with the back up I am getting from Tom. This thread will come in handy.

Shipping from Just Right Transmissions in Largo FL is about the same as from Monster transmissions.

I don't know if TCI offers a performance 4L60E but they do know what they're doing. GM Performance has several offerings but I'm not sure they offer one in our old one-piece case design. ACDelco or Goodwrench (if they're still around?) might have one with a good warranty anywhere in the country.