T-400 trans question - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Transmission - Rearend
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 11-11-2011, 06:29 AM
Registered User
 
Join Date: Nov 2011
Location: pa
Posts: 1
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
T-400 trans question

I have a th400 in a 1969 firebird, 3.55 rear, 25" tire. tach shows 3500rpm at 55mph. calculator says I should be at 2700rpm. trans and TQ conv are new 10/2010. 1800 stall. Any idea what might be wrong? tach and speedo are correct. thanks. also anyone do a 200r4 swap for a 69 firebird?

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 11-11-2011, 09:28 AM
Rustydawg's Avatar
Cruzin w/Elvis in Bigfoots UFO
 
Last photo:
Join Date: Nov 2004
Location: Edmonton AB, Great White North
Age: 48
Posts: 248
Wiki Edits: 0

Thanks: 2
Thanked 0 Times in 0 Posts
Something is way off here. You say that the tach and speedo are correct, but if this is in fact a 3.55 gear, with a converter that is relatively tight, 3500 RPM is out to lunch.

A couple of things come to mind:

The tach is set to 6 cyl.

The rear gear is more like 4.56.

The trans is not shifting into 3rd gear - it remains in 2nd.

Just for reference - a long time ago I had a Datsun pickup with a 4.38 gear and it would sit at 3600 RPM at 60 MPH, this with a 25" tire.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 11-12-2011, 12:01 AM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
Something's off ^^.

A 2004R will bolt in easily.
Same Crossmember.
Shorter DriveShaft with 32-Spline Yoke.
TV Cable and Brackets.
TCC Lockup Kit.
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 11-12-2011, 06:49 AM
Crosley's Avatar
Hotrodders.com Moderator
 
Last wiki edit: T-350 rebuild tech
Last journal entry: Bar under the dash
Last photo:
Join Date: Nov 2002
Location: ... USA
Posts: 8,101
Wiki Edits: 1659

Thanks: 340
Thanked 102 Times in 98 Posts
Quote:
Originally Posted by SSedan64
Something's off ^^.

A 2004R will bolt in easily.
Same Crossmember.
Shorter DriveShaft with 32-Spline Yoke.
TV Cable and Brackets.
TCC Lockup Kit.

typical 200-4r has a 27 spline output shaft
__________________
Some people are like Slinkies... Not really good for anything, but they still bring a smile to your face when you push them down a flight of stairs.
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 11-13-2011, 08:21 AM
SSedan64's Avatar
Registered User
 
Last photo:
Join Date: Dec 2007
Location: Macon, GA.
Age: 50
Posts: 6,016
Wiki Edits: 0

Thanks: 0
Thanked 46 Times in 46 Posts
Quote:
Originally Posted by Crosley
typical 200-4r has a 27 spline output shaft
Good catch Crosley, I must have had the 400 on my mind. why? I don't know.
Reply With Quote Quick reply to this message

Recent Transmission - Rearend posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
trans swap, 400 trans in 83 elcamino? renagade Transmission - Rearend 2 10-07-2011 09:45 AM
chevy 400 turbo trans output shaft question 57shaker Transmission - Rearend 6 05-24-2011 06:05 PM
th 400 trans 81 el camino Transmission - Rearend 5 08-09-2010 05:56 PM
65 skylark turbo 400 trans. install question skylark65 Transmission - Rearend 7 05-09-2007 09:29 PM
GM Turbo 400 trans front seal housing question Gary Shugart Introduce Yourself 1 01-13-2005 02:56 PM


All times are GMT -6. The time now is 04:41 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.