1996 Corvette 4L60e Rebuild or Transplant advice.
 

Hello all, 1996 CE LT1 A4, about 123k on the odometer.
The other day I lost 3rd and 4th gear while driving home on the highway. I had to get home in second.
So no 3rd, no 4th, and I got code P1870 - transmission component slipping.
The car is a daily driver and what I want from a transmission rebuild/ transplant is a noticeable improvement from the stock setup (shift kit),along with the strength/durability to last as well as be able to handle up to 400hp 400 lb/ft naturally aspirated in the future.

I have done a couple of searches and it looks like I have to either rebuild the transmission, or get a whole new one.

1. As far as rebuilding the transmission, do you think it is worth the time? I am a decent mechanic and can follow most procedures. Time wouldnt be an object as I can do the rebuild over the summer where Ill have more free time and daily the truck. I have a Chilton's repair manual on hand for any help, but would ultimately plan to follow -A rebuild of a 4L60e + Installation of Transgo shift kit. I know this isnt out of a vette but I think it is mostly the same and the rebuilder seems very knowledgeable and is very clear in what is being done..
If I rebuild myself I am looking at buying this kit: https://globaltransmissionparts.com/...uild-kit-9303/ along with a level 1 Transgo shift kit. This setup would be about $450 for parts alone.
I am also seeing a kit called "4L60E Master Overhaul Rebuild Kit With All Alto HEG Heavy Duty Frictions" from World Wide Parts Outlet. This kit seems to have all I need minus the parts to rebuild the pump, which I would like to do anyway. I would have to buy a Beast Sun gear Shell to finish it off. This kit, sun gear shell, and transgo shift kit would net me around $310
Im not familiar with brands/parts relating to a 4L60e rebuild however, and was wondering if one kit has better parts than the other? For example I see the second kit has multiple Alto parts whereas the first has mostly Raybestos items. Is one superior than the other? Are there better, complete kits that fit the bill?
If I decide against doing the rebuild myself (which I likely will for sake of expertise and time),what are the cost estimates to get it benched?
I am looking at spending around $500 for a kit and transgo kit. So what are your experiences with getting a tranny benched and rebuilt?
I am in the LA area and a shop called JD Corvette estimated:
$1750 for bench work alone
$2300 for a full service
$650 for RNI (Remove and Install)

2.I am leaning towards this transmission from Monster: https://www.monstertransmission.com/...l#.XNyK7-hKi00
It seems to provide a better shift quality along with the peace of mind if it being brand new, warranty available.
This tranny along with RNI is around $2000 and seems to be my best option overall. Have any of you used this transmission? Is there essentially a shift kit built in? Does my rear end ratio matter (mine is 2.59)? Would it be a direct plug and play deal? Should I get a new torque converter while im at it? Sorry for so many questions!

The car is my daily. Have had it for about 40k miles and has been a sweetheart so I want to do it right. I've recently upgraded plugs/wires and fuel pump/filter/pressure regulator, waterpump/coolant flush. I am trying to upgrade any parts that I have to replace with better quality as I go.

Any and all insights are very much appreciated!

The first thing you do is take the Chiltons book and tear out the pages and use them to wrap small parts in so you don't lose them. Then, buy the ATSG book and supplement. You will need these for the proper clearances. Take your time, check everything twice and keep everything clean. Use microfiber cloths instead of cotton or paper towel. Keep separate containers for each subassembly. Don't throw everything into the same pan like Hiram does. He has thousands of hours experience - you don't. Confab will be along to give you advice on friction selection. Use molded pistons for all your drums and spend the money for good quality sprag and roller clutch.

The second thing that you want to do is read the fine print on the web sites of the 3rd party aftermarket transmission sellers. Look carefully and you may well find that you have NO warranty unless you also purchase a new TC from them (which is most likely not included in the price you saw).

….. Google Monster reviews before you pull the trigger … find a tranny shop in your vicinity …..

If you do rebuild your self, make sure you use the newer style bonded pistons.
They are way easier to install.
I also bought a rwbuild video off of ebay, it was a huge help.
Next, the factory service manual was very helpful, and the atsg manual went into greater detail.

Be careful with the pump, and do not skimp on parts.
If there is a major part that comes from a kit in a no name box, replace it with a brand name like borgwarner or sonnax, transgo, etc.

I doubt the Monster Trans is "brand new".

As a reference, go look at the Sonnax site. they have recipes of parts requirements for different levels of builds. There has been lots of improvements in the transmission family since our cars came out. The parts that were used to upgrade to the 4L65 and 4L70 trans retrofit back to the 60E, such as 5 sprag pinion gears, other heavier duty internal parts. take the time with Mr. Google and do some extensive reading to educate yourself as to what can be done.

I will be doing the same to my '96 A4.

Yeah I started to become familiar with recommended brands after looking around more. I found that FLT and Performabuilt have builds that are better overall.
The FLT looks like the better option here, Sonnax SmartShell Pack, Borg Warner clutches/sprag. I am calling the shop today to see what parts their rebuild consists of to compare.
So far I am leaning into buying a built trans instead of doing the rebuild myself.

As far as the rebuilding a 4l60e, I am seeing that it is not too difficult compared to later transmissions. I would very much like to do the rebuild myself but I have my doubts as it is my first. ATSG in hand and a lot of attention to detail, cleanliness and TIME is enough to get the job done?

I am also looking into a built 4L60E for the project I am helping my friend with. I have a thread about it over in the C3 section. In essence we are going to get/have built a 4L60E that will easily handle 500+ and live. We are targeting a small block in the 450'ish range and I have all but the injectors, new balancer and seals/gaskets to build mine to the same level, so my transmission is going to need enhancement.

It's not too bad, just attention to detail and follow the atsg manual for testing via air prior to installing.

For the teflon shaft seals, i used electrical tape in order to size them down, and one of those long funnels would work to size it up.
Just get s few spares incase you end up nicking one or two.
Bonded pistons were my biggest upgrade, those lip seals are a pita.

After a lot of time and research, asking around, calling around, I decided to go with FLT's Level 4 + Trans Cooler and a Yank TC. The parts are there, the customer service is there (Chuck was very helpful and knowledgeable) and it seems to me that the majority of those that go with FLT are satisfied. I considered PB and monster transmissions but as you know monster seems awful and PB seems hit or miss.

I just have to find a decent torque converter. Any recommendations?
I am looking at a Yank Stealth Thruster 2800 Stall. What specs do I have to be aware of to ensure compatibility between the trans and TC?
Is there a way to calculate the actual stall speed for my 96?
I heard something about not going over 3000 for stall speed. Can anyone clarify this?

I plan to build the car mildly as time goes on.
Heads/Cam/Intake, 1.6 RR + supporting mods, Longtube Headers, gears(maybe), Z51 upgrade...etc.
It will serve as a mild daily. About 200 miles a week. Car has 124k on the clock., 96 LT1 A4 with 2.59 rear end. What rpm do you guys get at 70 mph and 3.07's?
I am also considering the gear change but am thinking about daily drivability.

I am more than happy to share any information about the whole process just in case anyone finds themselves in a similar situation.
The goal of the car is to be reliable (hence me going for a quality built trans) and still put that smile on my face, which it already always does.

With stock torque converter, less than 2000. I am thinking around 1800. After I tighten up a rear shock next week, if I remember, I will go out on the x-way and check. I get pretty decent mpg's and the engine isn't all spun up driving the highway for periods of time.

Depending on your ultimate hp goals, you can get a early Dana 44 (the 4+3) cars that has a 3.07 ratio. Or you can wait until spring and buy my Dana 36 with 3.07. It has 20K on it now (as does the car). I have to rebuild (bearings and seals) the D44 that I bought and put it in when I do the Banski rear suspension in the spring. I have too much to do this summer to do the car.

Remember, there are 2 different case sizes so if you just bought gears, you have to get the correct thickness ones.

I will make a note of the case sizes and thickness of gears, thank you.
Spring eh? That sounds like good timing for me my friend. What are the majors differences between the D36 and D44? Just overall robustness? I see that it has a thicker ring gear.
Honestly just looking for a solid 360 WHP.
Think Ill be good with the 36 and a gear change? Car is not launched a ton. Mostly canyon runs in second and third gear.
Speaking of which, in your experience do you find that the 3.07 ratio ever runs out of gear in the canyons or on windy roads? Talking avg 55 mph in the twists. Not too tight and technical.

I live in the flatlands of Ohio. However, going through the small mountains of Pa on the way to Carlisle, no issue pulling the hills at cruising speed. I like the 3.07 ratio.

In fact, we were looking at a complete new chassis for my friend's 1969 coupe, and the frame builder suggests a 3.07/8 (depending on which rearend generation is used) behind a built 4L60E. These folks are major players in the chassis market and are GM crate engine distributors. I think we can work it out better than the 50K when it is all said and done cost to do a frame with LS stand alone engine, etc. Not that he can't afford it, the money is already set aside, but since we live 18 miles from Summit Racing, 2 hours from Bair's Corvettes in Pa, etc etc, we can work it out.

The Dana 44 is a much more robust setup. That is why they put them behind the manual trans as they can handle the shock loads better.

Zip Corvette used to offer a heavy duty Dana 36 batwing (cover). Look inside this D44 cover and you can see the supports that go over the bearing saddle blocks. The D36's don't have these. The one Zip offered had blocks welded in. They ran out of components and I got tired of waiting so I bought the D44.

https://www.zip-corvette.com/85-96-d...ial-cover.html

Ikerd's used to offer it also, but the old machinist that made them the components passed away and I guess so did the knowledge (I guess).

You can see the inside of a Dana 36 batwing here: (click on the pic and it will expand).

http://www.mcssl.com/store/ikerds-in...e2f962e2c0382d