What is torque spec on front diff M14x80 bolts?
 

Does anyone know the troque spec on the forward M14x80 bolts/nuts connecting the front differential to the frame? I'm about to do the diff drop and was wondering for when I re-assemble.

They seem to be extremely tight from the factory. I haven't managed to get them off yet, although I haven't yet tried Liquid Wrench.

You'll need a 19mm wrench to hold the top nut and a 1/2" breaker bar with a 19mm socket to loosen the bolt from the bottom. You might need to use your legs to break it loose.

The torque spec is "Really F_ing tight". :D

Seriously, I don't know the exact torque spec, but 90-95 ft/lbs is probably a good start. Someone will probably chime in with the correct answer.

Hope this helps.
G

Well the book Im looking at says:

Differential assembly mounting bolt

front mount cushion bolt 116 ft lbs
front mount to differential bolt 116 ft lbs

Rear mount cushion nut 64 ft lbs
Rear mount to differential bolt 80 ft lbs

No pix, so I dont know where these are, but that was the spec given

Hmmm... I was using my torque wrench to loosen it, to see if I could determine the spec. I started around 45 ft/lbs and worked my way up to 150, at which point it started to turn, but then froze.

I wasn't holding the top nut (an oversight), so I imagine it was turning too. But, oddly, even with a breaker bar, and nothing securing the top nut, I can't get the bolt to budge. That strikes me as very strange.

I guess I'll get a new 19mm socket and then soak that puppy with Liquid Wrench.

Dropping the front 3rd
 

I have a question, might as well put it here.
I'm about to drop my thirds to send em out for gear installs. I can't find any good info about dropping out the front with ADD (1990 ExtraCab) All the articles I found so far don't detail what to do with the axles, maybe because they're writing about bearings or gears. I bought a Haynes book (only one they had...) and it doesn't show on word about ADD. It looks to me like the 6 bolt flanges on the axle shafts just unbolt at the ends of the stub tubes coming off the third housing. Slide em back a little (and support them with some wire or something) and take out the third with the short tubes attached. Is it really as easy as that? But on the Drivers side is the ADD mechanisms....

That's a different topic. (Not that it's not a good topic.) You should start a new thread.

I helped Mick (RidgeRunner) do his diff drop and we had to use a breaker bar AND and piece of pipe as an extension on it to get enough leverage to break that bolt loose. They can be a real bear. Liquid wrench, some elbow grease, a big breaker bar and the absence of fear are the key ingredients to removing those bolts. :)

All fun aside, just make sure the top nut is stationary and it should go with a little effort.

Good luck and let us know how it turns out!
G

I was able to get the bolts off using a 19mm wrench on the nut on top and a breaker bar with an extender pipe on the bolt on bottom. I was having a tough time breaking it loose, but then my buddy reached over and contributed a little elbow grease and it broke free. Having two guys pull is probably not a bad idea.

I went with the 116 ft/lbs spec that Yoda posted. It felt reasonable. And I actually had to then re-loosen them (because we forgot to put in the bottom washers the first time), and loosening them was very doable with just the breaker bar. I don't know if maybe it's the heat of the engine that makes them get tighter over time???

Anyway, mission accomplished. That diff drop is a very easy modification, and I can see the difference in the axle angles. Thanks everyone! :P

I know this is an old thread, but it had just what I was looking for as far as torque specs. My only question is for Yoda-What book were YOU looking at? A factory manyual? My Haynes didn't list it, as far as i could tell.

Hey Ian,
Long time ago, so I don't remember if it was the Factory service manual or the subscription service we have at work (I work in a fleet vehicle shop). The subscription is with Mitchell's manuals

Thanks Yoda. I don't see the subscription service coming my way, but perhaps someday soon ebay will yield a factory manual to me.

hey ian!

there are several members that have the fsm, i looked through some old emails to see if i could find out who sent me a copy. no luck on the name but try searching for factory service manual or fsm and see what you get.

lee