C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Help on 84/85 Tranny

Thread Tools
 
Search this Thread
 
Old Feb 17, 2008 | 10:58 PM
  #1  
bspvette's Avatar
bspvette
Thread Starter
Instructor
10 Year Member
 
Joined: Dec 2007
Posts: 184
Likes: 4
From: Hilliard OH
Default Help on 84/85 Tranny

I need to find out if a 700R4 from an 85 will be a direct bolt-in in place of the 4+3 in an 84. I assume that it would be dimensionally the same, but are there other retrofit concerns?

Do any of you have experience with this?

Thanks,
BeerMan
86 Rag Top
85 Coupe (#71 XP)
Reply
Old Feb 17, 2008 | 11:03 PM
  #2  
Demonic85's Avatar
Demonic85
Team Owner
 
Joined: Feb 2006
Posts: 24,460
Likes: 7
From: sw Ohio
Default

They're not the same length.
Reply
Old Feb 17, 2008 | 11:24 PM
  #3  
zr1fred's Avatar
zr1fred
Race Director
15 Year Member
Veteran: Marine Corps
All Eyes On Me
Top Answer: 1
 
Joined: May 2006
Posts: 10,691
Likes: 71
From: Phoenix Arizona
Default

Just get the package: flywheel, trans, tunnel housing, shifter and linkage, consol top, brake pedal, drive shaft, lock-up vacuum switch and wiring, cooling lines,and C-beam from a wreaked or parted C4 (pretty cheap, not much call for them, as most cars are autos).
Reply
Old Feb 18, 2008 | 02:44 PM
  #4  
CFI-EFI's Avatar
CFI-EFI
Race Director
10 Year Member
 
Joined: Sep 2000
Posts: 17,298
Likes: 33
From: The Top of Utah
Default

Originally Posted by Demonic85
They're not the same length.
Yes they are. But the "C" beam and drive shaft from the '85 won't fit. The 1984 "C" beam and drive shaft will be correct for the 1985 automatic transmission. Even the TV cable bracket is the same part. Any neutrally balanced 153 tooth flex plate will work, including the one from the 1985 donor car. The torque converter, if not with the trans, will need to be for an '85 and up with 30 spline. Most all 1984s had 27 spline, so if not included, get a converter for the 30 spline trans, not one for an '84.

Most of the stuff zr1fred mentions does have to be dealt with, with the exception of, tunnel housing (?), drive shaft, C-beam, and cooling lines. You could replace the cooler lines with the auto trans lines, but I'll bet it would be easier to just modify yours.

RACE ON!!!
Reply

Get notified of new replies

To Help on 84/85 Tranny





All times are GMT -4. The time now is 05:27 AM.

story-0
10 Ugly Corvettes That We Still Kinda Love

Slideshow: 10 ugly Corvettes that we still kinda love.

By Joe Kucinski | 2026-06-03 10:34:17


VIEW MORE
story-1
Top 10 Most Expensive Corvettes Ever Sold on Bring A Trailer

A lot of money has changed hands at the online auction house over the years.

By Brett Foote | 2026-06-03 10:21:50


VIEW MORE
story-2
10 Things Every Corvette Owner Needs (2026 Edition)

Slideshow: 10 great gifts Corvette enthusiasts actually want for Father's Day!

By Michael S. Palmer | 2026-06-03 15:43:40


VIEW MORE
story-3
8 Most "Only Corvette Owners Understand" Quirks and Problems

Slideshow: These are the quirks, annoyances, and oddly lovable problems that every Corvette owner eventually learns to live with.

By Pouria Savadkouei | 2026-05-28 09:31:39


VIEW MORE
story-4
10 Reasons the C6 Z06 is Still A Performance Benchmark After 20 Years

Slideshow: 10 reasons why the C6 Z06 is still a performance benchmark after 20 years.

By Joe Kucinski | 2026-05-27 17:20:09


VIEW MORE
story-5
How Much Horsepower Every Corvette Engine "LOST" in 1972

Slideshow: How much horsepower every Corvette engine lost in 1972.

By Joe Kucinski | 2026-05-27 16:54:53


VIEW MORE
story-6
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-7
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-8
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-9
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE