Rear shocks - '63-'66 vs '67-'72

[Greg63]

Last week I switched out my rear coils and shocks in my '63. All went well. I took the truck for a drive and it seemed to be very bouncy at first but settled down after a bit of driving. I was supplied with Monroe Matic-plus #32301 shocks and Moog 6101 coils.

I just referenced the part numbers on the internet and found that the coils are correct for '63-'66 1/2 tons with coils but the shocks are for '67-'72 1/2 tons with coils. Monroe lists #31000 for '63-'66 rear shocks.

I was always under the impression that the '60-'72 rear suspensions were all alike (generally). Why would there be two different part numbers for the different rear shocks? Should I return the '67-'72 rear shocks?
Greg

[lolife99]

Did you buy them locally?
I think I would return them and see if the #31000 shock is still available.
I assume your coils are the stock height?

[Greg63]

Got them locally, and the 31000's are available. The coils are oem replacements from Moog.
Physically, both shocks are the same (I looked at Rockauto's specs on them).
Must be some reason there are two different part numbers.
Greg.

[raycow]

Originally Posted by Greg63

Physically, both shocks are the same (I looked at Rockauto's specs on them).
Must be some reason there are two different part numbers.

Could be a difference in the stiffness. OEM had a bunch of different numbers that would interchange dimensionally but with different valving. Aftermarket usually tries to reduce the amount of inventory that has to be stocked.

Ray

[Greg63]

I have driven the truck a few times now since I posted this and it now seems to be "normal" again.
I received this response from Monroe regarding the differences in the two shocks;

That's correct. They do physically look the same, and yes, the valving
internally may be softer on the 32301 shock than that of the 31000. The
mounting styles are a little different as well. I have made a comparison
below:

32301:

11.875" comp. length
18.250" ext. length
6.375" travel
LS37 loop - loop mount which is 1/2" ID bolt hole, and 1 3/8" bushing width

(Embedded image moved to file: pic31762.jpg)

31000:

12.00" comp. length
19.50" ext. length
7.50" travel
L1 loop - loop type mount which is 10MM ID bolt hole, and 15/16" bushing
width

(Embedded image moved to file: pic28423.jpg)


Both shocks are Monro-Matic Gas charged shocks, but notice the slight
difference in the mounting loops.

For further questions or assistance, please contact technical assistance at
734-384-7809 M - F 8:30am - 5:30pm EST.

Monroe Team Member

Should I leave well enough alone?
Greg.