newoldvette

Hi, Im new to the vette world and Im hoping someone could shed some light on my 700r4 issue. I have a 85 vette with a 700r4.

1- will my 700r4 from my 88 firebird work?

Is the corvette transmission shorter?

2- will the driveshaft be 2 short?

3- will the tailshafts interchange?

4- if the tailshafts do interchange, will the holes still match up on the
c-beam?

5- Is it possible to drilll or notch the c-beam holes out and use the old driveshaft.

6- Is anybody using a non-corvette 700?

thx

ex-x-fire

The vette tail shaft has about 5/8'' removed, so you could cut the tail shaft on the firebird 700r4, swap over the tailshaft housing housing & speedometer parts. Everything should fit fine.
Make sure the tranny is for a v8, b/c they made th700r4s for the 60*v6 which has a different bolt pattern.

Cliff Harris

The Corvette has a completely different valve body. The case has a big "V" cast in each side to show this.

The other main difference is the tailshaft housing, which is specific to the Corvette because of the C beam. I would think that the tailshaft housings would swap. I think the output shaft in the Corvette 700r4 is a different length also (because of the tailshaft housing - not sure about that one).

The servo is also different, but those can be swapped. The Corvette servo has a larger apply area on the piston.

rodj

Some like myself have got away without trimming the shaft.
Forum trans expert Pete K says every swap he did needed the shaft cut.
Speedo drive gear needs relocating to the rear hole on the output shaft of non Vette trans when swapping the tailshaft housing over

vetteoz

1- will my 700r4 from my 88 firebird work?
YES
Is the corvette transmission shorter?
YES
2- will the driveshaft be 2 short?
NO
3- will the tailshafts interchange?
YES
4- if the tailshafts do interchange, will the holes still match up on the c-beam?
Completely different style housings , must use Vette housing to fit C Beam

oldalaskaman

this is excellent info

bjankuski

What kind of Firebird was the doner? If it was a 350 TPI it will have the good Corvette valve body that allows WOT operation in fourth gear. If is a base transmission it will not hold fourth gear at WOT.

newoldvette

Thanks guys for the great info. I was still wondering, if the tailshafts are interchangeable, (will the c-beam holes still match up?) It seems that if the transmissions are shorter the c-beam holes would be "off".
Am I mistaken

383vett

The transmissions are the same size. The output shaft of the f-body needs to be whacked 5/8" (use a cutoff wheel). Use the C4 tailshaft housing with the f-body transmission. Change the location of the speedo gear on the output shaft. That should do it.

Flame Red

My experience is that Vette tranny has many special parts not in other non-vette 700R4's. Yes, you can swap it and it will work, but it will NOT shift like your old vette tranny used to. Ask me how I know...

rodj

LOOK AT THE PICTURE.
The interchangeable tail shaft housing is where the length difference lies.
The cases of the T700 trans are identical length wise.

383vett

I ran a 700r4 from a full body Impala. With a transgo shift kit, it was fine.

rodj

Once you install a shift kit it over rides any stock calibration and there is no difference in the hard parts of the trans.

87 vette 81 big girl

All C4's with a 700 R4 had a specially calibrated valvebody.

Trans Go shift kit does not over ride all factory calibrations.

Only the 2-3 reprogram kit will set up for Full manual valvebody operation for drag race use does over ride all.

1986 to 1988 IROC CAMARO's are rumored to have same C4 Corvette valve bodies stock.

And the 1987 Pontiac Trans Am GTA.


The real test is the WOT 3-4 automatic upshift.
does it take place or not.
All stock C4's did this.
And held 4th gear till the driver let off the gas pedal.

BR

Muffin

Mine came from an 89 TA.

Rest of story: Was upgraded with a B&M Master kit and a shift kit. Tail stock, speedometer gears and output shaft swapped from the old Vette trans

tonyhward

I am actually considering an 89 Trans Am 700R4 for my 89 vette.... was the B&M and shiftkit needed to hold overdrive or would it have worked stock with the output mods ?

confab

It would have worked stock.. But your corvette has some HD parts in there that other 700/4L60's may not have.

I'd consider getting it rebuilt.

Cliff Harris

From what I've seen of a line pressure chart in the FSM, the Corvette version of the 700r4 has higher line pressures than the ones used in other cars. You can change that with a shift kit.

One thing I think is interesting is that the line pressure chart in my '86 FSM does NOT show the MD8 Corvette version.

Midnight 85

I don't know where you are located or if you would be interested but I have the original 700R4 out of my '85 that was rebuilt about 10000 miles ago. I replaced it with a 500 hp trans from Monster because I also upgraded my engine and was afraid the original would not handle the power. I am in central Illinois and pickup is the only option, I will not ship. The original converter was replaced at rebuild time and the new one is included.