Change Driveline Fluids Early!

[redone17]

Thank you everyone for your advice. Everything worked great! Amsoil 75w-140 F&R, BG Syncroshift II in the manual transmission, Ford Mercon LV in the transfer case. 23,000 miles, better late than never.

I’m running the same exact combo.

Sponsored

 

[Ziemann]

BG Synchroshift II is like butter in these MT88 manuals. Good choice.

 

[B22-2023]

I took today to complete front differential, transfer case, and rear differential fluid change at 4700 miles. As others have reported, I too found the rear differential in need of fresh lubricant. Replaced transfer case fluid with Motorcraft Mercon LV and both differentials with Valvoline synthetic 75W-90 fluid in flex packs. Additionally, I replaced the rear differential cover with the ARB unit ($177 shipped from Extreme Terrain) allowing for ease of future fluid changes. Love the magnetic dipstick and ease of filling the diff with fresh fluid using the flex packs.. Also the magnet on the drain plug is a beast!

I put the ARB on also, to get some more strength in the axle line.

As for fill level, are you using the dipstick for reference? To me I’m trying to set a mark that is top of the axle, but I’m curious what you think.

 

[HP11]

Yes, the cover will definitely provide added strength and I'm using the dipstick after first scribing a line on the dipstick that corresponds to the appropriate stock fluid level. I followed the guideline in the ARB installation sheet to align both covers first.
After installation and filling the differential, I used approximately 1.9 quarts of fluid. Your measurement may be slightly different but in my case the scribed line on the dipstick is 3 3/16” from base of the dipstick knob and 1” from the dipstick tip keeping in mind that when checking the fluid level you DO NOT screw the dipstick back in but rather place it in the opening to a point where the threads just touch... this per the install sheet.

 

[CarbonSteel]

Seems to me like a silly place for TTY. I'll be replacing with regular bolts when I get around to this.

But are they actually yielding here? I would think the gasket would make it hard to stretch them.

Given they are 8MM diameter and are only torqued to about 22-25NM, I would say they are not being torqued to the point of TTY. The gasket does have steel reinforcements at the bolt holes to prevent crushing the gasket and throughout the gasket surface, but the torque values are too low to see TTY especially since they are Grade 10.9 (essentially SAE Grade 8).

They are too short to be used with the OEM gasket and the Ford Performance cover so I replaced all of mine anyway, but can say that I never changed the bolts for AT LEAST 4 times on my Jeep Wrangler which has the same bolts and never had an issue.

 

[SierraBronco]

More of a “drivetrain” fluid than differential but decided to change the transfer case fluid since I had the skid plates off to swap out the driveline. 23,000 miles and dang. That stuff was darrrrrrrrrk.

 

[redone17]

Womp. Flange bolts link is dead.

The studs are zinc or black? What’s this yellow coated you speak of?

 

[CarbonSteel]

Womp. Flange bolts link is dead.

The studs are zinc or black? What’s this yellow coated you speak of?

Here you go:

https://belmetric.com/jis-flange-bolt-10-9-coarse-m8x1-25-12mm-wrench/?sku=BF8X25YLW

 

[redone17]

Thanks @CarbonSteel

Looks like all of the links are broken from your original post besides the studs. Which I don’t see in yellow coated either. Did you use zinc?

 

[CarbonSteel]

Thanks @CarbonSteel

Looks like all of the links are broken from your original post besides the studs. Which I don’t see in yellow coated either. Did you use zinc?

Yes, yellow zinc; I'll have to go back and edit the links to current. It appears that Belmetric made sweeping changes to their inventory listings and the links were broken in the process.

 

[redone17]

Yes, yellow zinc; I'll have to go back and edit the links to current. It appears that Belmetric made sweeping changes to their inventory listings and the links were broken in the process.

Ok, I’ll keep an eye out on an update from you.

 

[CarbonSteel]

Ok, I’ll keep an eye out on an update from you.

Wait, I may have misunderstood. Were you talking about the bolts or the studs?

 

[redone17]

Wait, I may have misunderstood. Were you talking about the bolts or the studs?

The whole list. It’s weird. The stud link works - but only has zinc or black. All other links say “Aw Nuts”. Clever. Haha.

 

[CarbonSteel]

The whole list. It’s weird. The stud link works - but only has zinc or black. All other links say “Aw Nuts”. Clever. Haha.

Updated the first page to make it easier to find, updated all links, and tagged you in it...

 

[redone17]

Thanks!!

Sponsored