741 Housing, 742 ring and pinion..... can it be done?
- Thread starter Cudafever
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crackedback thanks for the link! have ## now and can do some more research. What i have found out so far is that the 741 inner race(cup) is the same as the 742 OUTER cup. That's not much help, but wonder if there is a cup/bearing combo the might work........i'm sure someone should have thought about this long before now. only getting one answer, well....there's probably not a combination that will work.
If the cups were the same, it would be a simple thing.......but there not.
If the cups were the same, it would be a simple thing.......but there not.
bOb shingler
Well-Known Member
try mcmaster-car for bearings and such.
The bearing races for the carrier are the same for all 3 housings; pinion bearings are all different, I don't beleave you're gonna find a combination of bearings, races that will allow you to swap pinions around between the different housings. If it were possible, some one would know how to do it, information would be out there.
$64,000.00 question is WHY do you want to try this?
$64,000.00 question is WHY do you want to try this?
The answer is that i have 4.56 geared housing in my car that i don't want to mess with. i have three 741 housings. one with a clutch poss.
Wanting to put some 391's in to get my top rpm down at the top end of the 1/4 mile.
If i could fit 742 ring and pinion in a 741 housing........well that would be better then 741 ring and pinion in a 741 housing.
also 741 gears are a lot harder to find the, there out there but not so popular.
I'm not making that much HP, won't hurt a 741.........just thought it would be cool it that trick was out there.
And having it machined out the outer races/cup .3125(almost 3/8 of a inch) to fit the 742 race.....well that's a lot. Would probably create a weak link.
and yes i cant find a bearing/ race combo that will work.
The factory made gear sets down into the 5's (5.13's), and for a time the aftermarket (Zoom Gears, and I think Shaffer(SP?)) made gear sets for the 741 case. If you're looking for factory gear sets, look under /6 1/2 ton pick-up trucks. If all else fails, why not a set of 3.73's and a slightly shorter rear tire to get close to 3.91's .
Is a shame that the 741 housing isn't supported by the after market a little better; there's thousands of them waiting to be filled............
Is a shame that the 741 housing isn't supported by the after market a little better; there's thousands of them waiting to be filled............
SOOOO my search for the magic bearing has ended.........
It's a shame that the 741 housing isn't supported by the after market a little better; there's thousands of them waiting to be filled..
Yup and you never here of a 8-3/4 failing because it snapped the input shaft/pinion......even if it has the small 741 input/pinion shaft.
Just today, i talked my son out of his 3.91 poss out of his 73 pick up for some more "fuel economical" 3.55s.
It's a 741 housing as well. There both open diffs(shot cone poss on his) but i have a spare clutch poss with a new set of clutches to install.
It's a shame that the 741 housing isn't supported by the after market a little better; there's thousands of them waiting to be filled..
Yup and you never here of a 8-3/4 failing because it snapped the input shaft/pinion......even if it has the small 741 input/pinion shaft.
Just today, i talked my son out of his 3.91 poss out of his 73 pick up for some more "fuel economical" 3.55s.
It's a 741 housing as well. There both open diffs(shot cone poss on his) but i have a spare clutch poss with a new set of clutches to install.
They snap all the time at the yoke stress riser. Had plenty of them still attached to a driveshaft. Happens with the 742/489 pinions.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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That's about what I'm running with 3.55s, a stick, and 295s, but with a 742. No worries on the street, even with a CFII and a GVOD pounding on it. I did shred the 7290 joint tho, and tore the straps on another. The cure was 1350 joints and a u-bolt yoke.
The carrier bearings are specific to the type Sure Grip you are using The Clutch type uses 25520/25590. The cone type uses LM104912/ LM104949 bearing race. All three cases are easy to find. Just use the appropriate case.
Well that statement is ALMOST correct.
I have yet to find a 3.91 ring and pinion, for 741. Well i can find then on eval bay. but not new. 742/489 case. can find them all day and several brands as well.
I bet you there are more 741 housing out there then there is 742/489s combined. I found "a" 3.55 and that's it.
I have still been looking just in case the 3.91s that i'm pulling out of my sons truck look Worn and need replacing. so far i have not found one(new) 3.91 gear sets.
12+ years ago this was NOT a problem, when i got my 4.56. gears.
Why is my statement almost correct? I never said gears for the 3 cases are available anywhere, I said cases! Which one do you need? I can send you 5 of each! If you have gears for a 742, just get a 742 case. Why make this harder than it needs to be?
When i put my 4.56 gear chunk in, it got the 1350 yoke and a custom drive shaft to match. that reminds me, I my need to buy another yoke for the 3.91s, if the splines are not the same.
I have 3 free 741 case and "0" 742/489s If you want to relieve yourself of one of them, I'm ready to give you my address!!!!
Sure I'll sell you one, just PM me and we'll work out the details. Thou shipping a 35 pound box to Wyoming may be a bit costly.
You got me thinking here.........if the diameter is the same at the yoke for all three. then there is no power advantage, at this point, right? I when and looked, and it show a 10 spline for 742 and 29 spline for 489 didn't say what the diameter was.
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just to add some more info.
I found a site that stated that all pinion Yokes are interchangeable as long as the spline count is the same. apparently the 489 had a coarse spline with the early production of them.
In other words the yoke is the same side for all three........
Yes they are as long as they are the same spline count. 10 or 29.
AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Well the 489 used 7290 joints IIRC, while the 741 used 7260s. The 742 I have only seen one size but I don't recall which;7260s I think.
7260s do not put up with 400 plus hp, and 295s,on the street with a 10.97 starter gear, and a manual trans.
7290s seem to with the U-bolt cup retainers. I tore the straps off one of those 7260s,but the U-bolt type seems to be hanging on. The 7290 takes a different seal,too; and they're getting harder to find.
From what i have researched so far. 741,742 and Early 489 had a 10 spline. 741 used a 7260, 742 and 489 used a 7290 with a strap. You can get a 7290 yoke, with and upgraded u bolts for 10 or 29 spline. Top of the line 1350 that comes only with u bolts to hole on the cap, with 10 or 29 spline.
I think/ thought that my third member had the 1350 yoke........because it has u bolts holding it on. It my only be the up graded 7290 yoke. I'm going to have to jack my car up, and see which one i actually have.
I think/ thought that my third member had the 1350 yoke........because it has u bolts holding it on. It my only be the up graded 7290 yoke. I'm going to have to jack my car up, and see which one i actually have.
famous bob
mopar misfit
I didn`t read all these posts, but they have diff diameter pinion shafts don`t they ? the 489 even being tapered, the 742 was larger diameter than the 741, which is the weakest of the bunch.
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