Raven9

1978 R600 dump truck. looking for the rear shock mount brackets. thank you Gregg

So my compound box is shot, 78 mack R 300 twin stick, reverse keeps hanging up even tho the stick feels like it pops out gear, causing lots of problems working. Spoke with shop that used to rebuild the duplex and do these swaps all the time, says the parts for the compound box were obsolete about 10 years ago. A member has reached out on here and has a 13spd mack and a 8LL mack transmission to do my swap. At 2000 rpms I'm at 68mph. I am leaning toward the 8LL just didn't want to loose any mph with it, I'm in Missouri so lots of hills, hollars etc. just looking for some experienced advice. Thanks!

I’ve googled the Monroe, do you know if their front or rear? Or all the same? This is my first Mack so it’s been a lil frustrating on parts, I apologize for all the questions

Great, thank you!

Called Mack, they couldn’t come up with anything. Called Watts this morning as well, their working on it but nothing yet.

Hey guys, 1978 RS600L /vin# RS686LST38380. Having trouble finding shocks. Fleetpride gave me a monroe# 66886 but they are a tick long with the plastic retainer on them. its a dump truck, and trying to square this away before I do the trans swap. Still deciding between a 9LL and 13. 502 rears. also looks like someone has removed the rear shock brackets on this truck and I did not due my due diligence when I bought it as everything was painted the same color under the bed so i just glazed over, looked for frame cracks but is double framed, never even thought about not having shocks, i know im an idiot lol. any help with the shocks is greatly appreciated! Thank you!

Thanks guys, so if I stop, put the aux box in neutral then switch the pto on, no issues, but if I’m going in reverse and flip the pto on, then stop, and go to neutral, when I release the clutch it’s running the motor backwards, quite the scare for sure! I had to shut it off, and do restart to get it right. guess I didn’t realize you couldn’t be in reverse with it on, I was just trying to speed things up on my way to the box. @mechohaulic that’s exactly what was happening and what I had to do. this sight is so helpful and informative, a member has reached out to help me get parts to get the swap started. Thanks for all the replies!

@mechohaulic so I was engaging the pto while still in reverse, just before the tap on the box, then would put it in neutral, then the problems began.. im going today to back up then put it in neutral then engage the pto and see if that changes anything, Thank you for your reply! Im still learning on these trucks. now if I can get my door to latch ill be good to go lol

Started asphalt today, was hauling gravel, no issues other than the box hanging up sometimes going from direct to reverse. 5x5 trans. today, backing up to the box, when i took it out of reverse to neutral, got ready to lift bed, smoke started billowing out of breather, could not raise bed, i then put it in direct and 1st to pull out of the box, truck went in reverse. it caused my motor to run backwards. I have to shut the truck off, in neutral, restart put in direct and it works fine. made some calls and apparently the aux box parts are obsolete, called a guy who has done a ton of fro swaps in these trucks. My question is, why/ how is it locking in reverse and why is it causing my motor to run backwards? thanks for the info! 78 600r

I will see what I can do on more pics.! Aux box is wearing out, so off to Arkansas in dec to get a fro put in her, was hoping to find someone here in MO that has done the swaps, but no one yet.

After some long digging, I’ve found some older info on here, just need to source the bell housing and parts. mods can delete this post. Thanks.

78 R686, with the TRXL107 5x5. My Aux box is getting tough to get in and out of Reverse and Direct, I never use low. My question is, Would and Fro bolt up? Has anyone done a trans swap in one of theses trucks, I know ill have to change driveline, and other things, just wanting to get a 10spd in there and something I can get parts for in the future. I haul asphalt so a 10 or 13 would be the cats "meow" lol . It has a brand new motor in it so I really don't want to sell it and buy something else I know nothing about. Thank you in advance for your replies.

Purchased my 78 rs686 last summer, was a nice truck when I got it, new motor, decent interior tho im still fixing it up as I go. DIdnt really care for the blue, but its kinda grown on me, plus im not in the mood to change it at this present time lol.