FT Diff - Check your nuts

landtank

SILVER Star
 
 
Joined
Mar 27, 2003
Messages
19,491
Location
Groveland MA
Quite a few times I've come across front diffs that leaked from gasket between the axle housing and Diff carrier. It's almost always loose nuts. However while out at Cruise Moab on my final trail run @cruiserdan spotted a large oil spot moments after we parked for lunch and sure enough the nuts were quite loose and the gasket was torn. Luckily we were near the end of the trail and while I had a 36 hour drive home I'm part time so not a problem. Dan mentioned that Toyota at some point eliminated the lock washer for a flat one and that was likely the issue.

So I went on the hunt for better nuts and found some that I like. They are a JIS serrated flange nut, class 10.9 and zinc plated.

Today I tore apart the axle to replace the gasket and install the new nuts. As it turns out I did have lock washers they simple didn't do the job for me.

Attached are the before and after pics of the diff along with one of the nuts I used.

It takes 10 for an open diff. This is just the front diff and I'll get some for the rear and swap them out as well.
20180914_153246.jpg
20180914_160134.jpg
20180914_160126.jpg
 

landtank

SILVER Star
 
 
Joined
Mar 27, 2003
Messages
19,491
Location
Groveland MA
I had previously use FPIG on the failed gasket. I'll check these before my next trip but the truck gets very little use.

My rear diff is fine and I just ordered nuts for that and will change them out 1 at a time so no need to tear in and deal with the gasket as of yet.
 

chap79

Wheel. Break. Fix. Repeat.
SILVER Star
Joined
Mar 20, 2009
Messages
2,458
Location
Kansas City, MO
I’ve had this happen a few times too. Used blue loctite last time I tore into it and haven’t had the issue return :meh:
 

Cruiserdrew

On the way there
SILVER Star
 
 
Joined
Mar 15, 2003
Messages
15,605
Location
Sacramento, CA
It's only the front 80 diff that has this problem, but it's very, very common. I think the 8mm studs just are not up to the task. Or maybe there's some strange torque forces with the high pinion diff.

Anyway, check them every oil change, and I doubt you'll have further problems. And I got rid of the paper gasket up front too and went to the FPIG.
 
Joined
Dec 17, 2007
Messages
3,327
Location
Sydney, Australia
I replaced all the studs and nuts on my HZJ105 with 10mm studs when I had the diff carrier out.

Fairly common issue. I've used paper gaskets and FIPG and had leaks and loose nuts with both
 

davework

Cruiser Hardware: OverlandMetric.com
Supporting Vendor
 
Joined
May 6, 2005
Messages
729
Location
Erie, CO
For JIS Flange Nuts with serrations, the best place I’ve found for them is BelMetric.com. Reasonable shipping on small qtys. If Joey will stock them, even better though.
 

80t0ylc

Hill & Gully Rider
SILVER Star
 
Joined
Sep 24, 2008
Messages
2,802
Location
Canyon City, OR
Thinking about Nylock nuts, but they're temp limited.

"THERMAL PROPERTIES Most nylon insert locknuts are manufactured from Zytel 101 which has an effective temperature range up to 250 ° F. Zytel 103 has a higher effective range to 350 ° F and can be special ordered for your higher heat applications."

Would the Zytel 103 work or does the normal diff temps exceed that? Trying to remember what I've read with my laser thermometer when checking heat readings, before...:bang: ...damn dementia...lol
 
Top Bottom