I have 3 - 8 3/4 suregrip chunks. 2 have small yoke 1 has large yoke. I want to swap/sell the 4.10 big yoke for a 3.91/3.73 small yoke. Can I test the adjust this unit off the car? Its a 489 with cone type sure grip. The previous owner said it was just starting to howl.

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1966 Dart GT
4 spd. OD conversion
8 3/4 - 3.55 SG (Sold)

62 Lancer GT
B Body 8 3/4

A 4.10 big yoke, cone type sure-grip should sell for decent $$
(If you have a clutch type sure grip, hold onto it!)

As for testing a sure grip out of the car, you will need to insert some axle shafts and see if you can turn them in opposit directions, using all the leverage you can apply. ( big pipe wrench or a bar wedged accross some lug studs) If you can turn it by hand force, it's worn-out.
To be honest, I will not use a cone type sure grip, they just don' t hold-up or grip like the clutch type unit.
DD

My 4.10 is a cone type. I'll try your axle test thanks for the tip Doc. My 3.55 is the clutch type and thats the one going in my car.

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1966 Dart GT
4 spd. OD conversion
8 3/4 - 3.55 SG (Sold)

62 Lancer GT
B Body 8 3/4

I know you can rebuild the clutch unit. Do you have to remove the whole carrier and reset up the gears.?

_________________
1966 Dart GT
4 spd. OD conversion
8 3/4 - 3.55 SG (Sold)

62 Lancer GT
B Body 8 3/4

If the pattern is good & if the backlash is good, & if you carefully mark the adjusters and if you get everything back in the same position, theoretically, it could be done without resetting the backlash. That's a lot of 'ifs.'
The reality is that it is not that hard to reset the backlash, if you're in that deep, anyway. Don't forget to match-mark all the pieces, and get them back in the same position. Remember that the backlash is just half the battle. You have to crank in the proper amount of brg preload on the carrier bearings.

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'66 Cuda 225/4spd
'66 Dart GT convertible 225/auto
'64 Dart GT 340/4spd

If the unit has a "howl" then the gear mesh should be check by a professional before you take it apart. Look for a gear tooth pattern chart and let us know what the pattern is on your 4.10

If you know when and at what speed the howl comes-in, that helps diagnos the cause. (low speed decellertion, 40 mph "no load" cruise, etc.)
Looking at the gear tooth contact pattern will usually support what you hear out of the unit.

Other issues can cause a howl such as a failing crush sleeve, incorrect pinion depth setting, incorrect backlash, ring gear 'run-out", low oil level or wear on the gear teeth. (gear tooth contact surface)

In general, the lower the gear ratio, (higher numbers) the harder it is to get the gear noise out of them. This is because the lower ratios have a small pinion with a low tooth count. (a Mopar 4.10 should have 10 teeth in the pinion) When only 1 1/2 - 2 1/2 gear teeth are intersecting, the contact points need to be dead-on. (well centered on the tooth face)
DD

The 4.10 unit is for sale or trade for 3.91/3.73 small yoke. I just wanted the info for any interested buyers I wont be putting it in my car to test. I may check the pattern just to refresh my skills though its been awhile since Ive done it. Thanks for all the info. I may need it for my other units.

_________________
1966 Dart GT
4 spd. OD conversion
8 3/4 - 3.55 SG (Sold)

62 Lancer GT
B Body 8 3/4