742 sure grip set up question

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dgibby

dgibby

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Found a 742 case, clutch style sure grip and 3.91 gears fro a local guy but it is all apart. Local shops are wanting between 350 and 500 to assemble and set it up. Does that seem like a fair price? and or can I do the assembly and set up myself? Seems like when they come up for sale on the forums they are 550 to 600 ready to run. He is asking 350 for all of it but when I figure in the set up it seems like a lot to pay.
 
Do it yourself, it isn't rocket science. It does, however, require a dial indicator, a torque wrench that goes to around 250 ft lbs and a way to hold the yoke while you tighten it up.

Keep this thread alive with questions, there are several folks here that can walk you through it.

Depending on what he has with it you may need some pinion shims to get the depth correct.
 
Also, make sure the thrust buttons are in the suregrip if you are running the factory roller bearings, otherwise, you won't be able to set your axle end play (which by the way also requires a dial indicator) if you have the Green bearings it can be removed.
 
Is the shop charging you for new bearings in that price? I wouldn't be surprised, as I don't imagine most shops would want to assemble the rear with the old bearings. That would explain the higher price...
 
$350 for labor alone is too much. I think I could do the assy in 2 hours or so, starting with absolutely no idea what pinion shim to start with. OK, maybe 3 if it's cantankerous. So that would be $40 to $50Canadian to my son, $350 to you,lol. Kidding!
And the asking price of $350 is also too high, and here's why; You cannot know if the gears will pull a good pattern. If they don't, they will be noisy and IMO are junk. Plus they're 3.91s,not a desireable ratio. If it was fully assembled AND running a good pattern, then it's worth something; just not as much as 3.55s. Or even 3.73s. Course 3.91 may be valuable in some application, just not in a streeter.

AS an example;
I recently sold my 4.30s, which were dead quiet, low mileage, and with a fully functioning rebuilt cone-type SG,and in a 489 case, and with a large yoke, for $450Canadian.Yeah I kinda gave it away, but I doubt I'll miss them.
 
By a book and all the tools for way less than that and learn to do it yourself. Then you have learned something and an repeat it and make money doing it.
 
Does the 350-500 include a rebuild kit (bearings, shims, etc...? clutches for the suregrip? If so, that's not unreasonable at all. I still say do it yourself if you have the tools.
 
I have or can use all the tools needed to assemble it. Just wasn't sure if I was getting in over my head. The price seems a little high considering that I have to assemble it but by doing it I will know it is set up right. Wasn't sure on the ratio... I know there is a poll going right now. I run 3.23 with a 25.4 tall tire and its great on the highway but not so great light to light. 99% of my driving is in town, within 10 miles of the house with no highway so I thought the 3.91's would be good.
 
Yeah, the 3.91's will add some fun factor.

When you get ready to put it together just jump back in here. It really isn't that difficult as long as you get the gear mesh and tolerances correct.
 
Yeah Ima thinkin if 25.4 inch tires and a 3.23, are lazy...........You may be stuck with a small engine,and a 2.45low tranny, and a less than optimum tune.
A sharp teener should have no problem locomoting a Dart with those. A 225, well, not so much.On the other hand, even a lazy 360 should smoke that pretty much all the way through first.
So what engine and tranny do you have?
 
The 350-500 is for bearings only and the set up, no clutches
It's a 340 with a 727 3200 stall
It does pull hard and with a light foot brake will burn them from 1st and into 2nd. Cam is probably an issue, specs unknown but pretty sure it is a mopar purple 284 or 292 with a 2800-6200 rpm range.
 
So, do you need carrier bearings?

If so, make sure to measure the ends of the suregrip so you get the correct size.
 
Bad Sport said:
So, do you need carrier bearings?

If so, make sure to measure the ends of the suregrip so you get the correct size.
Click to expand...

Bearings look good but both shops only want to do it if they replaced them.
 
OK, well the 292/509 made my 11.2Scr360 a tad lazy too,off the line.It pulled real nice from 5500 all the way to 7200, with OOTB Eddies. I expect a short-stroke 340 might be even lazier. I dropped that cam like a hot potato. I really like my 230* cam.It's very torquey in my 360.
If the quoted price includes a rebearing then, well, the price of those kits is getting up there. I don't recall what price I paid for the last kit, but I do remember being surprised by it. So then the $350 still seems high, just a little less so.
That's the trouble with some shops.They like to sell parts ,cuz, well, there's good mark up on that kit.
But here's how I see it; If the rear end is assembled with used bearings, and it turns out to be whinny?, just try getting warranty. There's a good chance the shop will try to blame the whine on the used bearings, or the used gears. However with new bearings they have no out, and a whinny diff can only be; the used gears, or an incorrect assembly.For a city-car a whinny diff is only slightly annoying.
BTW, I whinny gear set, if properly set up, will be whinny forever. There's no such thing as; "oh, they just need a few miles to break in".
Tapered Bearings aren't rocket science. You can get eyes on them. If they look good, they probably are good.I have re-used bearings in my personal diffs, many times. And I have robbed used bearings from other used diffs, with no ill effects. And that would include the pinion bearings.
 
Well the deal might be going south. Stopped and checked it out and found a few things.
It's a cone style, not a clutch and the holes on the side look damaged, wallowed out a bit.
The pinion bearings are not the same size as the race in the case.
The he went down to 300 but not sure if it is usable.
 

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That is a common problem with a cone SG. That cross shaft is held in place with a .250x 1 inch or so solid pin. The cone SG only uses two small pinion gears, when the cone start failing to grip in the case halfs, it spins those two small pinion gears so fast to the point they get hot and weld themselves to the shaft. When that happens the only way they can spin is to rip the small pin where it is held in the case. At that point the hole in the case gets wattled out rendering the whole SG worthless. What has happened there is the results. Then someone tried to Mickey Mouse it back in service by welding the cross shaft in place. I have seen some a lot worse than that. i just took a 489 cone SG third member a part that had been welded a whole lot more than that. I suggest you pass on this one.
 
Spider gears got welded to the pin, sheared the locking bolt, wallowed out case = garbage.

SG is on the money along with Tracy. Look elsewhere.
 
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