My 700R4 feels like it's slipping on the 3-4 shift. It's been btween 30-40K miles since it's rebuild. It did sit for a year while I rebuilt the engine, but it has run fine for the last year. I haven't abused it at all. I plan on changing the fluid and filter. If that doesn't help, I'll run a pressure check. Any other suggestions?

When I have to rebuild it, I want to do it myself. Are there good guides for a hi-po rebuild on a 700R4? How many special tools will I have to buy?

 

Go to http://www.Levelten.com , Pat has rebuild manuals for the tranny, as well as better stronger parts. I had him rebuild mine. What an expensive tow job, though.

 

I'm having the same problem with my 700R4. The tranny hits fine from 1st to 2nd, but there's a "lull" between 2nd & 3rd that sends my engine rpm's screaming under full throttle for a couple of seconds until the tranny decides it wants to finally start to lock up. Same thing from 3rd to 4th gear. Gotta get this straight before I can realize the potential of my setup.

 

Not an "expert", but here what I do know:

The 1st to 2nd band also is used for the 3rd to 4th shift. Since there is more gear reduction in 1/2 gear, this is where it should show signs of slipping first (if it is the band). I just went through this on my 93 GMC Typhoon, and can verify that 1/2 shift is where it will show up first. Now the controls for the 2 different sets of shifting are different (valve body), so you may have a valve body gasket that has gone "south" or a check ball stuck or an acculator seal that is leaking. Also the servos used for the 2 different sets of shifting are partly the same and partly different, and are difficult to get to with the trans in the vehicle (at least on the Typhoon, so I assume as such with the Vette also). They come out the pass. side of the case, but very little room there.

Think it might be worthwhile to drop the valve body first, and check out the gaskets/check ball/acculator seals. See if all the bolts were torqued correctly first (must use a torque wrench - don't even think of doing this without it).

Hopefully you have a copy of the GM service manual. It really is the best place for the info you need.

 

Better start thinking about putting in a TH400 w/ Gear Vendors overdrive. That's what I'm in the process of doing. Wish I had done this before spending $2500 at Art Carr. Now I have a very expensive piece of junk lying on my garage floor. It only lasted 5000 miles.

 

Bob86ZZ4

Many people have 700R4's that have lasted over 100K.
The Tranny has to be built correctly.

Vic

 

Yep, you are correct. But, I'm just tossing out a different idea here. I sure wish I had done this last year. I'm pretty sure my 700r4 would have lasted longer if I didn't drive my car on the outer limits at all times too. So, I just wanted to let it be known that this is possible to build a better setup than just dumping all kinds of money into a 700r4 that may or may not last you. And tranny guy will tell you that a th400 can be built stronger than a 700r4. If somebody tells you that they can build a 700r4 stronger than a th400 you better run away from that one.

 

You are mistaken, you actually have it backwards. The lower gear ratio of 2nd gear makes the torque coupling easier. It's like starting a car with a manual trans in 4th gear...you slip the heck out of the clutch before the car moves.

If the 4th gear seems soft or slipping, the band could be burned, not worn out or improperly adjusted ( which will make a bang shift ).

If the trans has a "let loose" or "cut loose" event between one gear to another, it is an indication of excessive clutch pack friction/plate wear or bad clutch pack piston seals. A valve body problem could be responsible.

Both conditions require a rebuild.

 

Bob

I agree with you that the Turbo 400 is stronger than the 700R4.
No doubt about that.

But a 700R4 can handle 400 HP when built right.
For about $1500, it is a good deal.

A few people have had problems with the 700R4, but the majority seem to be happy with it.

Vic

 

After all the bad press Art Carr has been getting around here lately, I would prbably shy away from him. I've also heard levelten.com has a very good product.

 

Vic,

My opinion is that a 700R4 will last very well in stock applications, but any serious power is a serious problem. I blew my 5th 700R4 in July in my '85. 3/4 clutches started slipping. I finally gave up and bought a car with a 6 speed.