Welcome to the North American Subaru Impreza Owners Club Thursday March 28, 2024
Home Forums Images WikiNASIOC Products Store Modifications Upgrade Garage
NASIOC
Go Back   NASIOC > NASIOC Technical > Transmission (AT/MT) & Driveline

Welcome to NASIOC - The world's largest online community for Subaru enthusiasts!
Welcome to the NASIOC.com Subaru forum.

You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, free of charge, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, so please join our community today!

If you have any problems with the registration process or your account login, please contact us.







* As an Amazon Associate I earn from qualifying purchases. 
* Registered users of the site do not see these ads. 
Reply
 
Thread Tools Display Modes
Old 09-13-2020, 09:15 PM   #1
sebastian323
Scooby Newbie
 
Member#: 510671
Join Date: Jan 2020
Chapter/Region: SCIC
Location: California
Vehicle:
2006 WRX
Gray

Default Front differential jams when transmission case is tightened down to close it

The front differential on my 5 speed manual transmission jams as soon as I begin to tighten the transmission case shut. I have aligned the pins in the holes in the bearings on both the input shaft and the driven shaft. However, I did tighten the case shut when the pin was not aligned the first time I tried to close the case. Could this have damaged the case so that it no longer closes straight?
* Registered users of the site do not see these ads.
sebastian323 is offline   Reply With Quote
Sponsored Links
* Registered users of the site do not see these ads.
Old 09-14-2020, 08:27 AM   #2
Elbert Bass
Scooby Specialist
 
Member#: 283429
Join Date: May 2011
Chapter/Region: South East
Location: Down yonder.
Vehicle:
2016 Fuji Sunfire 03
Silver

Default

You could have damaged the case, yes. But more importantly:
Did you loosen the differential bearing carriers before you disassembled the case? Those bearings are preloaded and you can't just bolt the case halves together without removing that preload tension.
Although it isn't the service manual procedure - if you are using the same diff & pinion shaft and did not replace the diff or front pinion bearings then you can just count the turns you back the retainers out and retighten the same after the case is bolted together. Make sure your bearing races have not slipped partially out of the carrier and gotten in a bind.
Elbert Bass is offline   Reply With Quote
Old 09-14-2020, 06:35 PM   #3
sebastian323
Scooby Newbie
 
Member#: 510671
Join Date: Jan 2020
Chapter/Region: SCIC
Location: California
Vehicle:
2006 WRX
Gray

Default

Quote:
Originally Posted by Elbert Bass View Post
You could have damaged the case, yes. But more importantly:
Did you loosen the differential bearing carriers before you disassembled the case? Those bearings are preloaded and you can't just bolt the case halves together without removing that preload tension.
Although it isn't the service manual procedure - if you are using the same diff & pinion shaft and did not replace the diff or front pinion bearings then you can just count the turns you back the retainers out and retighten the same after the case is bolted together. Make sure your bearing races have not slipped partially out of the carrier and gotten in a bind.

thanks for the pointers! I spent some time studying preload and backlash today. I am using the same pinon and front diff. I will be backing off the retainers and re-setting the preload and backlash. It makes sense what you say about the case not closing up unless the retainers are not backed off to relieve preload tension. I did not previously know this.



And yes my bearing retainers did slip out of the case and I had to push them back down to where they were flat against the retainers and free to spin around slightly
sebastian323 is offline   Reply With Quote
Old 09-18-2020, 08:36 AM   #4
Elbert Bass
Scooby Specialist
 
Member#: 283429
Join Date: May 2011
Chapter/Region: South East
Location: Down yonder.
Vehicle:
2016 Fuji Sunfire 03
Silver

Default

Quote:
Originally Posted by sebastian323 View Post
thanks for the pointers! I spent some time studying preload and backlash today. I am using the same pinon and front diff. I will be backing off the retainers and re-setting the preload and backlash. It makes sense what you say about the case not closing up unless the retainers are not backed off to relieve preload tension. I did not previously know this.



And yes my bearing retainers did slip out of the case and I had to push them back down to where they were flat against the retainers and free to spin around slightly

Yes, if you are using the same diff/pinion and have not changed bearings on the diff or pinion shaft simply count turns on the retainers.
ALSO be sure and use Three Bond 1215 or equivalent on the case. Regular silicone is too thick and will change your preload.
Elbert Bass is offline   Reply With Quote
Old 09-22-2020, 11:16 PM   #5
sebastian323
Scooby Newbie
 
Member#: 510671
Join Date: Jan 2020
Chapter/Region: SCIC
Location: California
Vehicle:
2006 WRX
Gray

Default

Quote:
Originally Posted by Elbert Bass View Post
Yes, if you are using the same diff/pinion and have not changed bearings on the diff or pinion shaft simply count turns on the retainers.
ALSO be sure and use Three Bond 1215 or equivalent on the case. Regular silicone is too thick and will change your preload.

Thanks for the tips! My transmission is now fully re-assembled and installed on my car. It is working just fine. I loosened the differential bearing carriers until the transmission case was sealed, then I set them per the factory service manual procedure, which resulted in something about one tooth off from the stock setting. I decided to go with the orginal setting since I did not change any parts in the transmission. I wish I would have seen your tip about using the right sealant sooner! i used permatex black sealant.



Another thing I noticed is that if I tightened the driven shaft to the case before tightened the case down, the gears would mesh properly, whereas if I tightened the case and then the driven shaft, as per the factory service manual sometimes the front differential gears would totally bind up .
sebastian323 is offline   Reply With Quote
Old 10-14-2020, 01:03 PM   #6
GeoNV
Scooby Newbie
 
Member#: 518830
Join Date: Sep 2020
Chapter/Region: RMIC
Location: Colorado
Vehicle:
2009 WRX
dark grey metallic

Default

I'm curious- how's it been driving? I'm about to reassemble and just curious how it turned out for you.
GeoNV is offline   Reply With Quote
Old 12-09-2020, 02:15 AM   #7
sebastian323
Scooby Newbie
 
Member#: 510671
Join Date: Jan 2020
Chapter/Region: SCIC
Location: California
Vehicle:
2006 WRX
Gray

Default

Quote:
Originally Posted by GeoNV View Post
I'm curious- how's it been driving? I'm about to reassemble and just curious how it turned out for you.

So far everything is good transmission wise. I still am in the process of tuning the car and my mass airflow sensor is not fully scaled yet, so it drives like total trash at low speeds. I also have electronically disabled the turbo and have only gone 90 mph or so. But the transmission is holding up well.


When you re-assemble your transmission, be sure to loosen the preload on the front diff carrier bearings like the other user suggested and then set them back to the original position once you have closed the casing up. Also be sure to align the pins with the holes in the various bearings on the two main shafts. Check that everything spins freely as you close it back up. Hopefully I can post a video of me closing up the transmission later on. I have an extra unit I will re-assemble for the video. Any questions send me DM
sebastian323 is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not 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
Forum Jump

All times are GMT -4. The time now is 04:23 PM.


Powered by vBulletin® Version 3.7.0
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2024 Axivo Inc.
Copyright ©1999 - 2019, North American Subaru Impreza Owners Club, Inc.

As an Amazon Associate I earn from qualifying purchases.

When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission
Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.