Re-gear education please.

[daredevil]

Been racing 3600+ lbs b bodies with the 741 case and never broke one yet. Your results may vary and in some cases side effects may occur...............

with big slicks and a stall? Cranky you still set up to machine the cone grips? You know who i am right?

 

[Cranky]

with big slicks and a stall? Cranky you still set up to machine the cone grips? You know who i am right?

Yup, I still can machine them and I know who you are but danged if I can remember your name lol

Wait, I remember it!

 

[SandDiesel]

Saw this in A-bodies classified. What's the difference and what's preferred?

"Chrysler had two models, the clutch-type and bw. The clutch type uses many little clutches to lock up the diff and the borg warner type uses two cones. As I understand the inner cone bites into the outter cone lock up the diff."

 

[Cranky]

This goes back to the 'what one is better' when the subject of the cases comes up lol. Since BW decided this unit was to be a throwaway, they didn't offer rebuild kits, so a lot of people like the one with the plates instead of the cones. I end up with all of the 'junk' that others don't want because it's cheap so therefore, I have plenty of 41 case rears and the cone type suregrips IF you don't keep hammering on a Suregrip that has quit working, you won't hurt it in most cases. Not sure about the clutch type but I'm sure it will tear itself up too if you keep on trying to make it 'posi' when it has long since quit doing. Ok, now, if you have a cone type that still has all of it's guts in decent looking shape, the cones can be machined to work again. Been doing this for well over 20 years and have several of them making liars out of several who say it can't be done. A buddy is running one in his low 11 second 440 six pack Challenger and has about 3 years worth and he runs pretty much all season long. Btw, there are many brands of machinery that uses cup and cone clutch design so it's not a badly designed unit. It was just meant to be non serviceable in an automobile.

 

[Darter6]

Gear

Ya,3600 lbs, 3500 stall, 741 case, 4.10 gear, Hoosiers 27x10.5-15, 11.96@110 mph.

 

[Meep-Meep]

The cone type has a two pinion carrier and the clutch type (power lock) has 4. In theory the power lock should be able to take a higher torque load but since no one seems to be spitting out pieces from either one then it probably doesn't matter.

 

[Meep-Meep]

This goes back to the 'what one is better' when the subject of the cases comes up lol. Since BW decided this unit was to be a throwaway, they didn't offer rebuild kits, so a lot of people like the one with the plates instead of the cones. I end up with all of the 'junk' that others don't want because it's cheap so therefore, I have plenty of 41 case rears and the cone type suregrips IF you don't keep hammering on a Suregrip that has quit working, you won't hurt it in most cases. Not sure about the clutch type but I'm sure it will tear itself up too if you keep on trying to make it 'posi' when it has long since quit doing. Ok, now, if you have a cone type that still has all of it's guts in decent looking shape, the cones can be machined to work again. Been doing this for well over 20 years and have several of them making liars out of several who say it can't be done. A buddy is running one in his low 11 second 440 six pack Challenger and has about 3 years worth and he runs pretty much all season long. Btw, there are many brands of machinery that uses cup and cone clutch design so it's not a badly designed unit. It was just meant to be non serviceable in an automobile.

Just curious, do you use a taper attachment to re machine the surfaces or just use the compound? It's been a long time since I've had these apart and don't remember how long or awkward the parts are. I just happen to have the power lock units.

 

[Cranky]

Just curious, do you use a taper attachment to re machine the surfaces or just use the compound? It's been a long time since I've had these apart and don't remember how long or awkward the parts are. I just happen to have the power lock units.

If the O.D. of the cones look ok, I won't touch them because anything you take off will make them sit lower into the case half and you'll end up having to take even more off the faces which will only make then thinner which in turn will require thicker shims to make sure the spiders and side gears mesh well....help, my head is starting to spin lol. If they have never been machined before, I generally won't put shims in unless the gears look like they could use them...and I'd use the compound if I were to machine the O.D. as the taper might not have the range for that much angle. Never tried to go more than 10* with it.

 

[MarPar]

:confused2:

holy crap!!!

i had to read it three times, and i'm still not sure i got it all!! LOL

 

[74sundance]

I know of a few D-100 trucks 65-69,I think they all have 741's the door plates say 3:91 and one say's 4:10 would they be worth picking up the trucks at $250.00 just for the 741's?

 

[Cranky]

:confused2:

Holy crap!!!

I had to read it three times, and i'm still not sure i got it all!! Lol

lol

 

[Cranky]

I know of a few D-100 trucks 65-69,I think they all have 741's the door plates say 3:91 and one say's 4:10 would they be worth picking up the trucks at $250.00 just for the 741's?

Grab em! I've run plenty of them over the years and there's nothing wrong with the 41 cases and if they are SureGrips, the older ones will be the Power Lock. IIRC, the Borg Warner unit came out around late 68....or was that late 69? I used to find them in the local Pick a Part for 39 bucks. They actually charged more if it came from a truck....like 15 bucks more. Tried to explain to them that they were the same in cars and trucks but they didn't care....so I just pretended it came from a car Only thing you need to be aware of is when they sit for a long time and where the humidity is high, you might fine surface rust on the part of the gear that's not sitting in oil. When the weather changes from cool to warm and humid, it makes things sweat and over time, it lifts the oil off the surfaces and begins to rust but that's usually ok too. I've run lots of gears with rust pits and it doesn't seen to make any difference so long as there's still some original gear surface still there.

 

[74sundance]

Thank's Cranky....I know one's a '68 and it is a sure grip and so is the '69....One truck is a '65 and another is a '67 and one's a '70 and I'm not sure of the other two I'll have to go check this weekend.

 

[74sundance]

Hey Cranky here is some info you and a few others might like to see.....

Sure Grip
Sure Grip is the Chrysler name for a limited slip differential. It was optional on the 8-3/4" axles, 1958-1974. Two styles were used.

Dana Power-Lok
1958-1969 used the Dana Power-Lok (# 2881487). This unit utilized clutches for the differential locking action. The Power-Lok can be rebuilt using kit # 2070845 ( Mopar Performance [MP] # P4529484 ). In this assembly, axle driveshaft end thrust is taken by the thrust block assembly (replacement # 2881313). This Sure Grip appeared in the '741' and '742' assemblies. The axle bearings are: 25590 (Timken cone), and 25520 (Timken cup), (Chrysler numbers 1790523 and 696403). The Dana Power-Lok can be recognized by its bolt-together assembly, bolts around the side opposite the ring gear, and multiple openings exposing the cross shafts.

Borg Warner Spin Resistant
1969-1974 used the Borg Warner Spin Resistant (# 2881343). This unit utilized a spring-preloaded cone friction arrangement for the locking action. Axle end thrust is taken by the cross shaft. This Sure Grip appeared in '489' assemblies and 70 and later '741'/'742' assemblies. The differential axle bearings are: LM 104912 (Timken cone), and LM 104949 (Timken cup), (Chrysler numbers 2852729 and 2852728). The Borg Warner Spin Resistant unit can be recognized by its lack of bolts on the side opposite the ring gear (like the Dana), and two openings exposing the preload springs. Borg Warner sold this design to Auburn Gear who currently offers the replacement Sure Grip assemblies.

I found it here:
http://www.bigblockdart.com/techpages/875axle.shtml

 

[Cranky]

"The Dana Power-Lok can be recognized by its bolt-together assembly, bolts around the side opposite the ring gear."

I don't get that part unless it means the bolts are on the same side as are the ring gear teeth. The BW unit has it's bolts on the 'other' side lol. In this pic, you can barely see the case bolts on the right...they have a machined area for them to make up.

Can you figure which one is from a Dana 60?

I had some pics somewhere of the break down of them both and I'll post them if I can find them. Anyways, it's real easy to tell the BW from the Power Lock. The BW unit only has one window and you can see springs inside while the PL has several windows and no springs.

 

[Meep-Meep]

If the O.D. of the cones look ok, I won't touch them because anything you take off will make them sit lower into the case half and you'll end up having to take even more off the faces which will only make then thinner which in turn will require thicker shims to make sure the spiders and side gears mesh well....help, my head is starting to spin lol. If they have never been machined before, I generally won't put shims in unless the gears look like they could use them...and I'd use the compound if I were to machine the O.D. as the taper might not have the range for that much angle. Never tried to go more than 10* with it.

OK, that makes sense. I remember seeing a couple of units that were really tore up so to clean that up completely you would loose too much material and screw up the geometry. In addition I would think getting the angle of the cone and housing exact during the machining process would be the key to success. Otherwise you loose surface contact. A delicate operation to say the least! I suppose you can have the cones ground and hard chromed then ground back to size, but by the time that's done might as well buy a new one. I think I'll stick to my power locks.

 

[Cranky]

OK, that makes sense. I remember seeing a couple of units that were really tore up so to clean that up completely you would loose too much material and screw up the geometry. In addition I would think getting the angle of the cone and housing exact during the machining process would be the key to success. Otherwise you loose surface contact. A delicate operation to say the least! I suppose you can have the cones ground and hard chromed then ground back to size, but by the time that's done might as well buy a new one. I think I'll stick to my power locks.

Yeah, you can get into too much detail work to make it worth while. I have saved some extra cones that came from units where someone kept hammering them after it long since stopped working and acted as a one legger. What that does most of the time is it works the hell out of the spiders to the point they gall on their shafts then the shafts spin in the case fit breaking the anti rotation pin and when that happens, the case is junk so I'll save what's good and the rest goes to the scrap pile. Btw, I've seen the spiders wasted in the Power Locks too because of the same reason....when they quit grabbing, the spiders take the punishment but it usually doesn't trash the case unless spider gear chips get into the wrong places.

 

[SandDiesel]

Since I have the 741 case with open 3.23's, if I want to keep the street gear but want it sure grip what should I keep an eye out for parts wise? Lots of brands out there advertising new stuff but I'm on a budget so I'm surfing Craigs and that other site. Thanks.

 

[Cranky]

What you need is the limited slip unit which is called the carrier (SureGrip unit) and is like the pic I posted in post #35. You pull the old open carrier out, take the ring gear off of it and bolt it to the SureGrip unit and reinstall it. You will have to reset your back lash on the gears tho but will not have to bother with the pinion setting since that won't be disturbed...

 

[SandDiesel]

Thanks Cranky.