Sure Grip Rear • The Dodge Challenger Message Board

by **Anonymous** » 21 Apr 2001 22:11

Can anyone tell me an easy way to determine if a non-running car has (or had) a Sure Grip rear end? I have a donor car for the rear but before buying I want to be sure I am getting what I need.
Thanks

by **Hans** » 22 Apr 2001 8:03

Somebody told me once that you could check it as following : Lift the rear end of the car with the (bumper)jack so that both wheel are off the ground. Then turn one wheel while somebody else holds the other wheel steady. If it has a sure grip the "somebody else" should not be able to hold one wheel steady while you turning around the other.

This is what they told me sometime...Hope you know how I meant it. Good luck

by **Anonymous** » 22 Apr 2001 13:26

Thanks Hans! Anyone ever tried the method recommended by Hans?

by **alex** » 22 Apr 2001 22:28

If the axle is sure grip, with both rear wheels of the ground, spin one and the other will rotate the same way, if it's open the other wheel will spin the opposite way, there should be a tag on one of the carrier bolts saying something like "use limited slip diff oil only", alternativly, lift one wheel, and then try and spin it, it should not move if it is a grip diff, there is a torque figure to tell you how much force is needed to "break" the cones to test it for wear. the diff will probably be worn, but contrary to popular belief, they are repairable, if you know how.

by **frank** » 21 May 2001 4:39

the way hans described is true suregrips spin one way, you can also see what ratio rear end this way as well, if it is a dana it will have the number cast into it too...

by **Hans** » 21 May 2001 5:43

He Frank, can you explain me how to check the rear end ratio with the wheel turning trick ? I have heard about it but don't know exactly how. And Alex, with spinning the wheels, should you do that with the a/t in "P" or "N" ? There's a difference between that. I tryed it sometime and when the a/t in P the wheels both spinned in the same way but with the a/t in N one wheel spinned in the opposite way... But I'm pretty sure it has a suregrip or something cause I drove away with WOT and I put two stripes on the street.

Thanks

by **Jack T** » 21 May 2001 6:21

The axle ratio can be determined by turning a rear wheel one turn and counting the number of revolutions the driveshaft makes. Three and one quarter turns would make it a 3.23 to 1 gear ratio, for instance. Having a worthy assistant for this method really helps the accuracy, especially considering there's only a quarter turn of the driveshaft difference between a 3.23 and a 3.55 rear end.

by **dave** » 21 May 2001 8:48

Hans.
I am surprised the wheels move at all in 'P'. They should not move at all. That is why it is called 'Park'. Maybe they can move with both wheels off the ground but the driveshaft stays still? Have a look and see if the driveshaft moves.

Put the trans in 'N' and turn one rear wheel. If they both move in the same direction it is a sure grip.
In your case if one wheel is going the other way when in 'N' then you do not have a sure grip.

by **Hans** » 21 May 2001 17:13

Thanks Dave & Jack. Could it be something else then suregrip ? Cause as I said I can place a nice signature on the street with both wheels spinning around. And as I can see at some old bills of the previous owner, it uses slip. dif. oil. (don't know if that's saying anything but..) Oh yeah Dave, with trans in 'P' the wheels are turning but the driveshaft doesn't turn around.

by **Dave-R** » 21 May 2001 21:49

Try going around a corner burning rubber. You will see that only the inside wheel spins.

They will both work ok in a straight line only if they both get the same grip on the road. If one hit water or oil that wheel will spin.

by **frank** » 28 May 2001 2:27

boy hans sorry i didn't get back here to this thread, from what i read you have a limited slip differential,suregrips will only spin one way and always together. they did away w/them cause it is hard on them when you turn cause one is always turning against itself how i checked the ratio on mine was to put a chalk line on the top of the tire and the driveline then count revolutions of the driveshaft till the tire makes one turn,so what did you come up with? limited slips are still excellent rear ends for street use,but i have to say nothing is better than pulling away sideways from a streetlight w smoke coming from BOTH tires off the line,geez i
gotta go take a ride! lol.....

by **Hans** » 28 May 2001 5:38

Well Frank, I think i did something wrong cause I could only count less then 1,5 turns with the tire making one turn. I don't know if that's possible, I thought it should at least be 3 or something like that ...? And about the rear end, I have to recheck it once again cause i'm doubting what the wheels did. You said pulling away sideways, when I brake and burn my tires (just slowly) the rear end of the car went also to the left and right and showed two little stripes on the street. I don't know if you did mean that with 'sideways' but...

by **Madman Stephan** » 28 May 2001 12:49

Hi Hans,

did you have BOTH rear wheels off the ground?

by **hans** » 28 May 2001 16:25

Yes Stephan, why ?

by **dave-r** » 28 May 2001 18:02

Lets go over everything we have learned so far because this is getting confusing.

1/ Hans lifted both wheels off the ground Yes?

2/ With the transmission in neutral 'N' when Hans turned one rear wheel the other one went in the opposite direction Yes?

3/ Doing this and counting the number of times the wheel revolved compaired to the propshaft Hans got about 1.5 turns which is exactly one half as many turns as he expected Yes?

OK.
If all the above are true then logic tells me that we have not got a limited slip differential here.

If you now put one wheel on the ground and spin the other (you can because it is not limited slip) and again count the number of turns for one turn of the propshaft you will now find it turns about three times. I am betting 3.23 times. With both wheels off the ground Hans was turning one wheel 1.5 turns but the other was going 1.5 also but in the opposite direction!

Am I right?

by **Johnny-D** » 28 May 2001 18:56

So Dave, What kind of Rear do you feel is in his car?

by **hans** » 28 May 2001 20:10

I will recheck EVERYthing this week and let you know how it is for real. I think that's the best guys...

by **frank** » 30 May 2001 4:44

i looked in my 1970 challenger service manual for proper identification of a suregrip and it says lift rear of car, if both wheels turn the same direction simultaneously it has a suregrip,it also says you can remove the fill plug and look w/a flashlight to identify the type of differential case, so if you do this and only one wheel turns one way and the other turns the other then it is NOT a suregrip.i would try checking your ratio again like i said w/a good chalk mark and possibly an assistant.

by **Larry M (Larrylava)** » 13 Jan 2003 22:00

I have a 70 challenger 340 with a 8 3/4 axle
with 489 case.The car also is an A66 package
Can someone tell me if this will have a suregrip
LSD?..I can always jack the car up and turn the wheels,I am unable to locate D91 option on the
fender tags or on the build sheet.

Larry

by **Dave-R (Roppa440)** » 14 Jan 2003 11:21

I would guess that with the 340 pakage you would get a suregrip because they were put together identically to a R/T in every other respect. The only sure way to check if your car still has it after 30 years is to (as you know) jack it up and spin a wheel.

by **Mike Lanouette (Mikel)** » 14 Jan 2003 16:14

D91 WOULD NOT BE LOCATED ON THE FENDER TAG.IF YOU HAVE YOUR BROADCAST SHEET IT WILL BE LOCATED AT THE TOP LEFT UNDER D91.IF THE CAR CAME WITH A
SURE GRIP THEIR WOULD BE A "1" UNDER THE D91

by **Larry M (Larrylava)** » 14 Jan 2003 17:55

You're right Mike,,I found it on the broadcast
sheet..hard little bugger to spot!

Larry