knikula

I just bought my first Corvette (pretty cheap), an 84 with a sickly 700R4 with 140K miles on it...

I spent a few days reading all the 700R4 posts I could find, and have watched a lot of 700R4 rebuild videos.

I appreciate all the posts shared on here.

This car is kind of rough, but it fits me pretty well, looks cool in the garage sitting up on blocks, and in the dark. Motor runs pretty well, but the plugs are AC, and might be the original ones.

I bought the car from a guy who bought the car at an auction (Bart Starr's Rawhide Boys Ranch in New London, WI), so I don't know any history on it. The PO said he bought it to fix, and lost interest. He said it would not shift passed 2nd.

The outside of the trans pan is super clean, the trans fluid looks brand new, and the servo and governor cover have somewhat recent looking RTV sealant on them. The exhaust manifold studs are pretty rusty, so they have not been recently removed. The catalytic converter air tube is attached to the exhaust manifold with a small screw type hose clamp, with does not look factory.
Factory tag on the transmission says 4Y9 and a little Y.

Bought a pressure gauge and the ATSG manual for it, and various pressures seem to be fine according to the manual, with idle pressures around 70 psi in park, rising quickly with any throttle motion.

A brief road test had the car shifting out of first(or second, I'm not sure), and then seemingly hit a "neutral". Slipping would be the wrong word for it as the engine just revs freely.

I have the car up on blocks in my garage now. In 1st gear, there is a ticking sound that reminds me of a stuck lifter at idle. When the trans shifts to second, the sound goes away. On the shift into 3rd, the sound returns, but at a much higher frequency. it shifts into 4th around 55mph, ticking noise may be gone there, hard to tell. There is no ticking noise in reverse.

When I first got the car, the TV cable had slipped , and I readjusted it. This was before I had the pressure gauge. I could see a witness line on the plastic where it was very clean, and I moved it back to that position.

I plan on pulling the trans and possible attempting to rebuild it, depending what I see inside. I have never attempted to rebuild a trans before. So far I have the exhaust removed by breaking off all the exhaust manifold studs. Good times...

Now I have to raise the car higher (about 21" ) and remove the C beam.

Question:

1) Are the 3 torque converter bolts assembled with heat removable loctite? Or can I remove them with a box end wrench?

2) Any predictions on what I'll find in the tranny?

3) Any suggestion of repairing the exhaust manifold studs? I plan on drilling them out from underneath the car. Looks like a pretty straight shot.

Anyway, still thrilled with the non-functional car....

Regards,

Ken (in the UP of Michigan)

JrRifleCoach

IF that is in fact the original trans, there are a multitude of updates/upgrades available.

But before you start dumping money into this project you need to stop and think about value.
An 84 in pristine condition is worth maybe 10K if you can find a buyer.
You'll need to be good at wrenching and trouble shooting.
Finding a source of free/cheep parts is a must. Maybe a donor car.
An 84 with 140K is in need of many different levels of repair.

This is the right place for help and many here can give sound advice and assistance.

Good Luck

WVZR-1

The Y9 is the earliest transmission code and if you couldn't document any visible signs of a rebuild assume it's likely original I'd think.

You won't have any trouble removing the torque converter bolts. I would think the preferred removal of the exhaust hardware is a constant soaking with (my choices), either Kroil or a 50/50 mix of Acetone and ATF and wrenching. Heat if you had some maybe. Drilling I believe should be a last resort effort. ** First read I saw the "rusty" - a later read I see twisted off so it's an entirely different game I guess.

The worm style clamps on the AIR tube for an '84 I believe are stock.

I'd say maybe you assess the value of the car to you, check the balance of the mechanicals and maybe make run well first and then/last maybe consider a reman trans with all of the upgrades that were done through the years. I don't believe I'd consider a fix of yours unless it could be confirmed it was just an adjustment of sorts or very minor repair. Maybe get running, do some adjustments, check pressures and reconsider everything.

ex-x-fire

I'd get a used tranny, from later years. It doesn't have to be a c4 700r4 (though that's what I'd look for), you can use one from a Camaro. You would have to swap over the speedo gears & extension housing & cleanly cut about 5/8" off of the slip yoke splines.
On mine you can barely see a dimple where the hole was when they machined it on a lathe.

knikula

Thanks for the thoughts...

I'm a somewhat old guy (56) with no job, who has time to tinker with this kind of stuff, and I like a low budget challenge.

I have a source for a donor trans out of a TransAm, but I want to see what this thing looks like while torn apart.

Last car project was a 1981 VW Rabbit Convertible that I converted to turbo diesel powered... pretty easy swap, that gets about 45 mpg. Not many diesel convert's around...

thanks again.

waynelap

I replied to your PM before I seen your post. I can give you the email of the guy that rebuilt mine since your not that far away. He is in Windsor so you could bring the trans over the border with no issues ( plus your $ is worth more and would save you some cash). I would stay with the Vet trans since some of the internals are better than those from other cars and they shift better also.

knikula

progress report:

I had the car up on the blocks with the rear wheels free to turn, I could get the tranny to shift thru all 4 gears, but with a ticking sound in first somewhat like a bad engine lifter, no ticking sound in second, a faint ticking sound in 3rd(much faster ticking tho), and 4th was quiet. Took her up to about 70mph in the garage, kinda spooky. Kept thinking about the Darwin awards.

I pulled the tranny, it seemed pretty happy on those bellhousing locating pins, had to wiggle a bit. I wish they would have made those bellhousing bolts with a deeper head. Hard to keep the socket on squarely.

It seems I have the weaker 27 spline version, date code on the pump of 2/28/83. 27 splines as counted on the larger (stator?) splined shaft.

I removed the TCC lockup solenoid, pump , and found when removing the 2/4 band, that the servo bracket on the band had detached from the band, and was laying in the case. Guess that would explain the "no second gear" in the road test. Odd failure, I think... riveted bosses did not hold.

I'd guess the servo pin was applying just enough pressure on the broken band to make it accelerate the tires with no load. The input drum looked ok to me, pretty smooth with a few visible areas of contact.

I put a dial indicator on the 3/4 clutch pack, and it reads about 0.100" of end play, versus a .085 max limit on new parts. Since I have it apart, might as well get in deeper, and replace all that wearable stuff.

Since I have the weak 1984 27 spline tranny, and the mighty 205hp crossfire, I'll try to rebuild it pretty much stock, with some better friction materials anyway. When I manage to remove that little snap ring on the first planetary, I'll get a chance to check out the sun shell.

Managed to cut the previously broken exhaust studs flush with a small abrasive wheel. Those things are toasty when they fall down your shirt.
This should make it easier to drill new holes.

My tranny doesn't have a "V" cast into the side, but it does say MD8.
The valve body has 2 pressure switches, and one solenoid for the lockup TC. Someday I'll break down and buy a FSM and find out what the ECM is looking at in the tranny connector.

Random thought: I'd like to rebuild a '93 to '97 4L60E, and then build a controller to control the shift speeds, lockup, and pressures based on throttle position and speed. Pretty easy to do these days with the arduino type controllers, I'd guess. Transmissionbench here:

http://www.transmissionbench.com/4L60Evideos.html

has some good videos, and an explanation building a Schaffer switch for testing the 4L60E.

I'll work more on the beast tomorrow.

Regards,

Ken