Hot Rod Forum : Hotrodders Bulletin Board - Reply to Topic
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> T-400 speedometer gear question
User Name
Password
lost password?   |   register now

Thread: T-400 speedometer gear question Reply to Thread
Title:
  
Message:
Trackback:
Send Trackbacks to (Separate multiple URLs with spaces) :

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.



Additional Options
Miscellaneous Options

Topic Review (Newest First)
07-31-2013 01:27 PM
sqeezeit Ok guys, update on issue.i found out I'm my own worse enemy of stupidity!after further looking it seems there is no speedo gear on the tail shaft.lol
07-29-2013 06:57 AM
sqeezeit Thanks for everyone's input very much apreciate it I know I have smaller housing with the right size smaller tooth count driven gear just don't know why it doesn't make contact with the drive gear on tail shaft? When I get home in a couple days will look a little closer and update status. Thanks again
07-29-2013 05:56 AM
zooma
Tooth Count and Housings

Not sure if you got the answers your looking for yet. The drive gears on your Output shaft can be either 14 or 15 tooth counts. The plastic one is a 15 tooth gear, the metal one looks a lot smaller and could be incorrect. You will need to trace one tooth on the gear from beginning to end, then count the remaining teeth to determine the count. 400 driven gear housings will work with any drive gear, they range from 34-39 and 40-45. To determine what you need go to transmission center.org to use their speedometer gear calculator.
07-28-2013 08:29 PM
cobalt327 ------------
07-28-2013 11:15 AM
Crosley Photos of T-400 output shafts. I have these parts on hand. I dont need to search the web for photo stuff that may be correct or not. .. hope this helps

T-400 both shafts:




T-400 metal gear:




T-400 Plastic gear with clip:

07-28-2013 01:50 AM
sqeezeit
Quote:
Originally Posted by mmerlinn View Post
As noted by several before me, you cannot mix and match speedo gears and housings. The gears (40 & up) with larger tooth counts are larger in diameter than the smaller gears (39 & under) to accommodate the extra teeth. The larger diameter requires a different offset so the teeth make proper contact with the drive gear.

If your gear and housing match, then you have a different problem, possibly, as noted above, a missing or loose drive gear.

What is confusing to me here is that you say you have the smaller housing (39 & under I presume), yet your gear does not contact the other gear. If you had a mismatched housing and gear in this instance, you could not even insert the assembly into the transmission without using a bigger hammer and ruining the gear(s) in the process.

How about counting the teeth on the driven gear and posting the tooth count and the casting number(s) on your housing? There may be something else at play here that is not obvious without more info.
I never did count drive gear teeth yet,and I think it was yellow in color,not sure.I do have the right housing and driven gear,it is a 36-39 housing.I know the 40 and up are bigger diameter of driven gear so wont fit my housing(tried it before I knew this).Will get back with more info,but just wondering if the drive gears are different diameters also?Could it not have the right drive gear,from what I read theres a few different tooth count drive gears but I guess didnt or wouldnt think it wouldnt even touch the speedo/driven gear if it was wrong,I dont know.
07-28-2013 01:42 AM
sqeezeit
Quote:
Originally Posted by Crosley View Post
The T-400 speed-O housings are divided into 36-39 and the 40-43 tooth designs.

The T-400 stem of the plastic gear is a different diameter for each housing tooth count design. You can not interchange the gears between housings. A 44 tooth gear will not fit a T-400 housing for 36-39 tooth gear or the other way around.

I suggest you verify the correct parts are on the T-400 output shaft, then verify the driven gear and housing. I had a fellow a few years ago , trying to install speed-O housing for a torque flight into a T-400.
Yes this is exactly what Iam trying to do, what u last said in message
07-28-2013 01:00 AM
mmerlinn
Quote:
Originally Posted by sqeezeit View Post
Are the speedo drive gears all the same physical size?I ask because I have a smaller tooth gear housing and the speedo gear doesnt even make contact with the drive gear on the output shaft?Someone told me that I might need the 40-45 tooth housing because it offsets the gear more to make contact?I am just wondering if its not something with the drive gear being wrong also.Any one have any ideas.I guess I hate to buy new housing and still not work.
As noted by several before me, you cannot mix and match speedo gears and housings. The gears (40 & up) with larger tooth counts are larger in diameter than the smaller gears (39 & under) to accommodate the extra teeth. The larger diameter requires a different offset so the teeth make proper contact with the drive gear.

If your gear and housing match, then you have a different problem, possibly, as noted above, a missing or loose drive gear.

What is confusing to me here is that you say you have the smaller housing (39 & under I presume), yet your gear does not contact the other gear. If you had a mismatched housing and gear in this instance, you could not even insert the assembly into the transmission without using a bigger hammer and ruining the gear(s) in the process.

How about counting the teeth on the driven gear and posting the tooth count and the casting number(s) on your housing? There may be something else at play here that is not obvious without more info.
07-27-2013 12:23 PM
zooma I think this site will get you to the speedometer side of there business
transmission center.org
07-27-2013 12:19 PM
zooma
Info Link for your speedo issues

Try this site for some additional info on T-400 driven and drive gear set ups
AOD, AOD Performance Transmissions from PATC, AOD Transmission, AOD Mustang, AOD
07-27-2013 09:32 AM
cobalt327
Quote:
Originally Posted by sqeezeit View Post
Thanks but not sure that helped,Ive seen that page and says nothing(unless I missed it) about different size drive gears(not tooth count).Iam wondering if something came loose on the install,because my drive gear on tail shaft is towards the engine to far,maybe it slid out of place on the shaft?
The drive gear should be basically directly under the driven gear housing hole in the tail housing.

If you have a plastic drive gear, there's a spring steel clip that has one end secured in a hole in the tailshaft. The other end snaps the drive gear into place. There's a chance the drive gear was knocked out of position, or the wrong size clip was used instead of the correct clip.

Steel gears used on some early transmissions are a press fit and I seriously doubt you'd be able to move one out of position under ordinary circumstances, so if there's a steel gear and it's loose enough to be bumped out of position you need to replace it altogether.
07-27-2013 07:03 AM
Crosley The T-400 speed-O housings are divided into 36-39 and the 40-43 tooth designs.

The T-400 stem of the plastic gear is a different diameter for each housing tooth count design. You can not interchange the gears between housings. A 44 tooth gear will not fit a T-400 housing for 36-39 tooth gear or the other way around.

I suggest you verify the correct parts are on the T-400 output shaft, then verify the driven gear and housing. I had a fellow a few years ago , trying to install speed-O housing for a torque flight into a T-400.
07-27-2013 06:32 AM
sqeezeit Thanks but not sure that helped,Ive seen that page and says nothing(unless I missed it) about different size drive gears(not tooth count).Iam wondering if something came loose on the install,because my drive gear on tail shaft is towards the engine to far,maybe it slid out of place on the shaft?
07-27-2013 04:38 AM
cobalt327
Quote:
Originally Posted by sqeezeit View Post
Are the speedo drive gears all the same physical size?I ask because I have a smaller tooth gear housing and the speedo gear doesnt even make contact with the drive gear on the output shaft?Someone told me that I might need the 40-45 tooth housing because it offsets the gear more to make contact?I am just wondering if its not something with the drive gear being wrong also.Any one have any ideas.I guess I hate to buy new housing and still not work.
There are both large and small gear sets.

More here.
07-26-2013 09:05 PM
sqeezeit
T-400 speedometer gear question

Are the speedo drive gears all the same physical size?I ask because I have a smaller tooth gear housing and the speedo gear doesnt even make contact with the drive gear on the output shaft?Someone told me that I might need the 40-45 tooth housing because it offsets the gear more to make contact?I am just wondering if its not something with the drive gear being wrong also.Any one have any ideas.I guess I hate to buy new housing and still not work.

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


All times are GMT -6. The time now is 12:37 AM.


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.