So, I found a small leak coming from the inspection cover weep hole on my 95 40,000 mile corvette. I changed out the tranny filter and gasket because the pan bolts were about finger loose. I thought that might be the problem. I filled it up today and let it run for about a minute. There was a constant drip from the weep hole in the bottom of the inspection cover. I now have to drop the tranny and change the front seal. This is my first C4 and it does not look fun...haha. I have been working on cars since my father who was a master mechanic started teaching me at the age of 5 or 6 about 40+ years ago.Any pointers would be greatly appreciated. I will start this project when it gets a little warmer here in the next week. Thanks guys for all your help ....this a GREAT site.

Hammer

 

Dunno about a 95, and specifically the exhaust, but the older C4's are a piece of cake.

I had to remove mine and I had to heat the exhaust nuts to get them off.. SS nuts on reinstall fixed that problem and I would recommend them.

Use red loctite on the converter bolts.

The bushing actually takes the pressure and at 40K it is hard to believe there's a problem there, but it is possible so inspect the converter snout when you are doing this and if you see obvious issues there, rebush the pump. (Doubtful, but.. )

Be careful under the car. A 4L60 is heavy enough to hurt you if it slips.

A proper transmission jack is a big plus. Even one of those transmission "jack saddles" on your floor jack makes it much nicer.

Be sure the engine doesn't tilt back and mess anything up.. I dunno what you have to interfere there, but take a quick look for wiring and whatnot behind the engine before you begin. Supporting the oil pan lets you manipulate it separately, rather than just pulling the trans off and dropping the engine.

Replacing the lockup oring isn't a bad idea either.. It's from 95 after all and they harden and wear. Take you two seconds.

This is important: One thing I have seen repeatedly on bench jobs is guys who to not get the converter seated properly and do pump damage on startup. When properly seated you shouldn't be able to get more than maybe a fingertip between the converter and the pump. It should spin freely while you are installing and it should be necessary to pull it forward to the FW between about 1/4 and 3/8 of an inch. If you can't do this STOP, because you converter is not seated. Putting some lubricant in the pilot in the crank and on the bellhousing studs is a good idea also. (You must have both dowels or it will leak) The pump rotor is cast and easily broken, so be sure to get the converter seated and check it during install. If something did happen to go wrong here, STOP.. It is a cheap fix and isn't the end of the world till you start it. THEN it's the end of the world.

Take a look at the flexplate. I found cracks in mine and replaced it while I was there, saving myself a future problem later. Cracks, chipped starter teeth, etc.. They're cheap and it is a piece of cake while you have the trans out.

In the flexplate there is one converter bolt hole that is smaller and this is the alignment hole. install that bolt first and the other two will automatically be aligned for you! rotate the engine so this hole is accessible, and do it first. Use a screwdriver to push the converter forward to meet the flexplate, rather than using the bolts to pull it up. Be double sure you don't catch any wiring and that the trans is flat against the engine before you crank the bolts down.

In 95 there should be (I think?) a flat, spring retainer you have to remove to get the seal out. if it isn't there, add one.. Places like WIT Transmission have them and the oring in stock.

Good luck, bro!

 

THANK YOU SO MUCH. I REALLY NEEDED THIS TYPE OF INFORMATION/EXPERIENCE TO HELP MOTIVATE ME. I have done these seals before but never on a 4L60E or a C4 Corvette. Mostly on my old classic muscle cars. I have all the right tools and equipment but I was injured in the Army during Operation Iraqi Freedom and it’s not as easy as it used to be to crawl under cars anymore. I just won’t give up on my dreams. I love cars more than anything except God and family. I have never owned a Vette and my wife pushed me ( I really love her for it though) to finally get my dream car. Sorry for the long rant. Thank you again sir. This place is truly a wealth of information.

Hammer

 

If something unexpected happens, stop and post.. We'll hook you up!

 

Confab, I just found out that there a bulletin put out by GM in regards to fluid leaking from the pump body in the 95 and 96 Corvettes. It says to replace the bushing. Is this hard to do? Bulletin number 57-71-26B ..revision on 02/06/97. What is this lockup ring you speak of. I want to replace all the parts while it is out and on the bench. Thanks again sir.

 

Disclaimer: I own a transmission shop.. So, no.. It is not hard. And it is not hard for me.

But if you make a mistake, you can cause severe damage very quickly.

If you are not comfortable doing this, you may really want to consider hiring it done.

What it involves is standing the transmission up, removing the pan. Removing solenoids from the VB and the pump, popping the pump out, taking it apart, removing the seal, removing the bushing, driving another one in, properly aligning the pump halves, and the putting it all back together without altering the transmission end clearance or otherwise creating a situation that makes it lunch the front half of your trans out when you fire the engine.

I'll be happy to help you if you think you are capable.. If not? Perhaps you should ask a local transmission shop to bush it for you and then you just reinstall it?

 

PS: The parts are cheap.. You're probably looking at 30 bucks.

Mess it up, and you're looking at 1600 or more, depending on your market.

 

PSS: I've got a dozen old pumps in the back.. So I'll even show you in pics if you want..

But if you break it, it's on you bro..

 

Thank you sir. I most definitely have the mechanical skills and tools but would really appreciate your expertise on the matter. I have rebuilt many manual trannys and countless engines/rearends but have never really needed to dig very far into an automatic. You will be a life saver. I am very **** about precision and torque specs. My wife calls me a perfectionist and I wont disagree. I take all responsibility for my actions on this end. I would look to to you as an instructor/expert only. Which actually means a lot to me. You are the pro, I am not. I will follow every word you say. Thank you again.

 

Okay..

First, you will need some parts. To make this easy, the "Paper and Rubber" kit is all the gaskets in the transmission and all the soft parts, and is probably cheaper than pricing them out individually. So, you can change the lockup ring, solenoid seals, pump slide seal, etc, as you go..

Part Numbers:

Paper and Rubber Kit: 74000E
Front seal: 74070
Pump Bushing: 74034B
Retainer, if you don't have it: 74089


If you want a tech manual to guide you, it is: 74400E

You will need something to stiction it all together while you are working. Transgel is the usual thing, but you can also use grease. It seems like a shame to buy a whole tub of gel for this small job, but if you want it the number is: M465TG

Although it is doubtful at 40K, if you see wear on the rings and vanes, you can replace them with kit # 74533K

These part numbers are from the WIT Transmission Catalog, but they should be good for ATC/Transtar or whatever they call themselves now also.

There are some special tools, but they are costly and unnecessary if you are careful.. If you want them I can get you the numbers, otherwise we'll hilljack it!

If you are interested, you can download the entire catalog here:

https://www.wittrans.com/catalog

 

WOW, that is awesome. Thanks. Going to print that schematic. I was able to get 99% of the exhaust off. Waiting on a bolt to soak some Break-free

 

Where can I buy the correct bushing driver for the 4L60E? I have a small lathe but I think buying one made for this tranny would be better. Any advice on a what tools I need specifically for the 4L 60E? Thanks again. You are a man of integrity. Is there a chance I could get an e-mail or cell number I could use to ask questions? I promise I won’t bother too much. It might be a slow process working on this tranny. I still have some physical limitations but am a very stubborn soul...haha.

 

I'm not near it now.. I'll measure it for you tomorrow.

I literally have like, a grand+ in bushing drivers hanging on the wall. They're costly.

The proper way to seat a bushing is with a press anyway, but I drive mine because faster.

You can buy them but for one bushing it will be expensive.. Let me measure it and see what you have that may work for this one instance first.

 

PS: As far as special tools go, there's a H-Gauge, drivers and a pump alignment band. I have them all here, but they are cost prohibitive for one repair.

If you are careful you can get around those with hilljack technology.

I'll do pics.. It will be okay.

 

My bushing driver measures about 1.858/1.733, which is pretty much the perfect size for the pump bushing.

But, you can drive it out with a sharpened punch and probably press it back it with a socket if you are careful.

 

When I get it out, what are the chances I could ship it to you to put in the new seal and bushing. I have until mid July before it needs to be done. That is when the Black Hills Corvette Rally starts.

 

Sure.. You can ship me the whole pump if you want. That's fine.

But the bushing is easy.

The more difficult part is getting it all back into place without messing up the end clearance, and totaling it when you hit the key.

None of this is particularly hard but it is a "Skill Level A" project.

 

What are the chances it’s only the front seal that is bad. The GM bulletin says that those two years had trouble with the bushing pushing the seal forward and out. I thought it had a step inside as a stop for the bushing? Were the later years better? My 98 Z28 doesn’t leak a drop and it has 109,000 miles. I beat on it once in while and I don’t beat on the Vette with only 40,000 miles. Is the 4L60 better in the 98 cars than in the 95/96 cars? Is there a design difference? Thanks again.

Hammer