741 pinion nut torque

[1966satellite]

Anyone know what to torque the pinion nut on a 8 3/4 "741" rear end? I saw a table that called for 40 ft lbs but that doesn't sound right.

 

[Bolt-Action]

240 Ft. lbs.
IIRC for the small stem,
You maybe looking at turning load;
Turning load should be 20-30ft lbs w/new bearings, maybe 5-10ft lbs w/old bearings

 

[bm02tj]

the preload should be in inch lbs not foot lbs

and it can take 2 to 3 hundred lbs to crush the sleeve

 

[khryslerkid]

Turning load? I thought 240 ft lbs of torque was 240 ft. lbs. Please explain...

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the preload should be in inch lbs not foot lbs

and it can take 2 to 3 hundred lbs to crush the sleeve

It's a crush sleeve isn't it ?

 

[GrabberOrange69]

Turning load? I thought 240 ft lbs of torque was 240 ft. lbs. Please explain...

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It's a crush sleeve isn't it ?

Turning load = how much torque does it require to turn the pinion in the assembly. It's a method for measuring how "tight" the pinion and ring gear bearings are.

 

[khryslerkid]

Gotcha

 

[Bolt-Action]

the preload should be in inch lbs not foot lbs

and it can take 2 to 3 hundred lbs to crush the sleeve

my bad on the inch vs foot...

 

[1966satellite]

The "741" does not use a crush sleeve. I know the correct torque for a "489" is 240 ft. lb. but I don't think that's right for the "741".

Turning load? I thought 240 ft lbs of torque was 240 ft. lbs. Please explain...

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It's a crush sleeve isn't it ?

 

[bm02tj]

if you use solid spacer you still have to shim as you still need to have the rotating torque correct
and yes the torque will be up in that range 2 to 3 hundred foot lbs

 

[Cranky]

Pretty hard to put that much torque on them without the proper tools.....but whatever you get on it, Loc-tite the nut. Yeah, the bearings are supposed to have some preload and that's measured in inch pounds but, it's supposed to be done without a seal. About the only way you can do that is to set it up without a seal, mark the location of the nut, then install the seal. Screw all that tho. I just put them together to get a good 'feel' and call it good. Been doing it that way for 25 years with great success. No crush sleeve on the 41 or 42 and with the 89, the crush sleeve goes in the trash and a solid spacer goes in.

 

[5.7 hemi]

I'm with cranky on this.

 

[Bolt-Action]

Yeah, you can't reuse a crush sleeve either, a solid spacer you can (as long as it isn't knackered), but shims are necessary (as mentioned)
the 8 3/4" is similar to a ford 9" in that regard.
without setting the proper preload, your pinion depth will not be correct, I've seen many a gear thrashed by improper set-up.
it takes a LOT of torque to get that preload correct.

My question is; did you change your ring and pinion gearing?
If so, youre more than likely going to need different shims than what you took out before the gear change.

 

[Cranky]

When you are setting up a rear with shims, pinion depth won't change much if any once you get past 100 ft lbs on it. The shims will dictate preload beyond that. When using a crush sleeve, it's going to take a lot more than that just to get the thing to crush and if you go beyond that and crush the sleeve too much, you've got a locked up rear and the sleeve is now junk. Like I mentioned earlier, it's hard to book build these things without the right tools but if you have a very sturdy vise mounted on a good sturdy bench and a torque wrench that's big enough, then you can get there but an old timer (I'm there now!) showed me how he did his and it's still working. One of the things that helped me out a lot is a damn good impact but now a days with the way my back is, I try not to mess with them anymore.

 

[Bolt-Action]

Agreed, the first 100lbs is easy! Lol
after that its minute amounts, but I wasn't referring to you Cranky, I was addressing the OP still,
but you already know that you TECHNICALLY should not use an impact on the pinion nut, crush washer or spacer (but it sure does make it easier)

 

[dartguy340]

The "741" does not use a crush sleeve. I know the correct torque for a "489" is 240 ft. lb. but I don't think that's right for the "741".

x2...There is no crush sleeve in a 741 casing.

 

[1966satellite]

741 torque

Anyone know what to torque the pinion nut on a 8 3/4 "741" rear end? I saw a table that called for 40 ft lbs but that doesn't sound right.

Thanks for all the help guys! as I understand it: the 741 does not use a crush sleeve. bearing preload is determined by shims. When it is shimmed properly it should take about 10 in. pounds to turn the rear end. The nut should be torqued to 240 ft pounds to prevent loosening.

 

[Bolt-Action]

It could take more or less than 240 ft. Lbs., and also if you're reusing your old bearings, it could take less or a smidge more than 10 in. Lbs., new bearings around 20-30 in. Lbs.,
also as cranky suggested put a dab of locktite on the threads and I always mark my pinion nut with a paint pin in a couple spots

 

[383man]

The 741 uses shims to set pinion brg prelaod and pinion depth. The large shim under the pinion inner brg on the pinion is used to set pinion depth. The smaller shims that go on the pinion collar are used to set preload. Torque it to 240 ft lbs but keep turning the pinion as you torque it and if it gets to tight to turn stop and add shims. If you go to 240 and dont have 20 to 30 inch lbs on new bearings then take some shims out. The idea is to tighten the pinion nut to 240 ft lbs give or take 20 ft lbs and have 20 to 30 inch lbs turning torque on just the pinion and its bearings. No crush sleve in the 741 as just the 489 uses a crush sleve. Ron

 

[bm02tj]

and after it is set up install a new pinion when you install the seal

 

[bm02tj]

and after it is set up install a new pinion (nut) when you install the seal

I missed the nut at the end of pinion sorry