Picked up this B61ST Dump Truck

[jessecam]

I picked up this B61ST mack I found in the back of an old gravel pit last year. Last fall I did a quick glance but did not look over really well, the interior was tore up with animals living in it. Had it towed home (50 miles) yesterday after I changed the rotted out steer tires. I spent the rest of the day cleaning it out and seeing what options it had to determine to use for parts for my B42 or restore. One of the local said it used to be there lowboy truck and in the late seventies early eighties they put A dump box on it to haul asphalt, but the pit was sold in 1986 or 1987 and he doesn't remember the truck running after that. I am awaiting information from the mack museum. I was a little disappointed in it having a ten speed unishift that they altered to a dash air switch, cracked frame, driverside rear between rear axles, floors rotted and fabricated for dump body. I am impressed with fenders, frame, rest of cab in being in great shape which I believe is due to not being used in winter and sprayed down with diesel fuel and transfluid twice a day so asphalt would not stick to it. I will try again today to see if I can get it started but can not get the engine to turn over. If stuck, anyone have the easy way to brake lose. there is still antifreeze in it and oil is full with no water in it or the fuel tank. I have added some pictures and will keep update on progress.

[Wobblin-Goblin]

Nice find. Good work cleaning the interior. Looks better already.

[Red Horse]

Unishift control on dash says to me this was a pit truck for sure in its final years No need for split shifting!

[mrsmackpaul]

socket and real long piece of pipe on the handle on the crank on the front of the motor if you can get to it or perhaps a pinch bar on the ring gear

once you get it move just a little rock it back woulds and forwards till it will roll on its a bit at least that is what I would try

good luck

Paul

never heard of a uni shift before

[Vladislav]

Good find indeed.

I agree, you need some while to figure out what to do with it.

From the pics it looks restorable.

If you're going to try the crank to turn ower it's better to put some fuel into cylinders and let it stay for a week or so. Than try to turn.

The result might be too different. It it's stuck really hard due to rust in the liners the only way is repair.

Good luck on the project.

Vlad

[41chevy]

socket and real long piece of pipe on the handle on the crank on the front of the motor if you can get to it or perhaps a pinch bar on the ring gear

once you get it move just a little rock it back woulds and forwards till it will roll on its a bit at least that is what I would try

good luck

Paul

never heard of a uni shift before

[1958 F.W.D.]

If it's stuck, pour a mix of fuel and ATF into the cylinders. Let sit for a week.

[Maddog13407]

they made a TRD67 and TRD72 series uni shifts. I think the earlier ones were called Mono shifts? seen a few and EVERY one is missing the green Uni shift Medallion out of the shifting ball.

[jessecam]

The engine was not stuck and turns over free but didnot try to start yet, I had issues with the 24 volt starter. Does anyone know were is the air switch for the unishift (high, low) supposed to be mounted, how durable are they and are there any parts available.

[Maddog13407]

suppose to be mounted right on the shiftin lever with a brass flipper switch with a funk flat Mack shifting ball. the lever originally had a hole near the bottom and one near the top where the cable came up thu the shifting lever

[Green Dash]

they made a TRD67 and TRD72 series uni shifts. I think the earlier ones were called Mono shifts? seen a few and EVERY one is missing the green Uni shift Medallion out of the shifting ball.

I have a picture of most of a knob.

[farmer52]

Years ago I looked at a B with Unishift. Personally I liked it better than a twin stick (only need one hand to shift).

[mowerman]

used to run one,,,,hated it,,,it would hang up in nuetral alot,,,,looks to be in pretty good shape,,,good luck with it,,,,,bob

[j hancock]

Lots of meat left on the bone with that find!

[Maddog13407]

gotta be a rare find to find an R model with a Uni shift....

[mowerman]

gotta be a rare find to find an R model with a Uni shift....

looks like a U model...bob

[jessecam]

The transmission in this B has a regular shifter, but the switch they screwed to the dash is air switch, not mechanical linkage. I thought the unishift would be an air shifter. I will try to get numbers off the transmission today. from the forum it looks like the numbers to be on the drivers side of the case?

[41chevy]

The transmission in this B has a regular shifter, but the switch they screwed to the dash is air switch, not mechanical linkage. I thought the unishift would be an air shifter. I will try to get numbers off the transmission today. from the forum it looks like the numbers to be on the drivers side of the case?

It is air / mechanical, the mechanical link is from the clutch arm to the air shift cylinder on the trans and from the pre select switch on the shifter to a selector on the trans ( for hi or lo range )

From oldmacks

This is a listing of transmission options for various B models. Do not consider this to be a total list of transmissions.

The explanation of transmission letters and numbers below

TR -- 5 speed transmission without compound box attached.

TRD -- 5 speed transmission with 2 speed compound box attached.

This is called a duplex transmission.

TRDL -- Same as above but with aluminum case. L stands for weight

reduced or light weight.

TRDX -- Same as TRD but with low hole gear. X stands for severe service.

TRDXT -- Same as above with the addition of a transfer case for front wheel drive.

TRT -- 5 speed transmission with 3 speed compound box attached.

This is called a triplex transmission.

TRTL -- Same as above but with aluminum case. L stands for weight

reduced or light weight.

TRTX -- Same as TRT but with low hole gear. X stands for severe service.

TRQ -- 5 speed transmission with 4 speed compound box attached.

This is called a quadruplex transmission.

The numbers following the letters tell sizes and revisions.

The last number will tell some important features.

0 -- Transmission is overdrive in high gear

The following do not apply to straight 5 speed transmissions

3 -- Transmission is called a mono-shift

30 -- Transmission is called an overdrive mono-shift

5 -- Transmission is called a uni-shift

50 -- Transmission is called an overdrive uni-shift

[jessecam]

Did not find numbers on transmission, a lot of cake on grease, did find mack patent just above oil filler. Could the numbers be somewhere else. I could wait till I recieve info from the museum.

[Maddog13407]

numbers are on a flat machine surface below and to the right the patent numbers and Tetrapoid gears logo and right next to where the front and rear case bolt together

[mowerman]

mine was a cable that ran to an air shift.....bob

[Gmerrill0516]

She looks like she still has a lot of promise left in her. I guess knowing if the engine is good bad or otherwise is a big piece of information. Once you know if it runs well or not you can probably see a clear path. I like the fact it is a tractor. Is the dump box really made up with plywood or am I seeing things? Either way, many guys have made nice trucks from less...

I can't imagine driving a unishift that would hang in neutral all the time...sounds dangerous and frustrating.

Keep us posted and good luck. I hope it runs great and doesn't smoke.

[jessecam]

Finally had time to find transmission numbers. See pictures

[jessecam]

She looks like she still has a lot of promise left in her. I guess knowing if the engine is good bad or otherwise is a big piece of information. Once you know if it runs well or not you can probably see a clear path. I like the fact it is a tractor. Is the dump box really made upwith plywood or am I seeing things? Either way, many guys have made nice trucks from less...

I can't imagine driving a unishift that would hang in neutral all the time...sounds dangerous and frustrating.

Keep us posted and good luck. I hope it runs great and doesn't smoke.

Thanks, I will be working on it next week to try getting it running, the 24 volt relay and solenoid under the seat had me stumped for a little bit But i think i have it now. i was told the plywood was added to the outside of the steel to cover dents and help keep asphalt warmer on longer hauls especially the michigan weather. I dont know if I believe that.

[jessecam]

attached is a picture of the numbers for the front tandem axle. I believe the R445 is the ratio?