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Mikedriggers · 09-08-2017, 01:54 PM

Trying to get my motorhome running to take to the lake. 6v92 Detroit pusher/Allison ht747 tranny. Been sitting up for five years and was given to me by a friend's widow. Cranks and runs great but has no power to untrack itself...acts like airbrakes are still on but jacking it up the tires spin freely. I just drained the transmission and changed the filter screen and the in line spin on filter and no change. It will back up but has no power to go forward...any suggestions is appreciated

CountryB · 09-08-2017, 04:42 PM

Quote:

Originally Posted by Mikedriggers

Trying to get my motorhome running to take to the lake. 6v92 Detroit pusher/Allison ht747 tranny. Been sitting up for five years and was given to me by a friend's widow. Cranks and runs great but has no power to untrack itself...acts like airbrakes are still on but jacking it up the tires spin freely. I just drained the transmission and changed the filter screen and the in line spin on filter and no change. It will back up but has no power to go forward...any suggestions is appreciated

Does the engine sound and rev normal in neutral?

Did you change fuel filters?

Any exhaust smoke when trying to move? If so, what color?

Mikedriggers · 09-08-2017, 05:25 PM

Engine sounds great, all new fuel filters, checked and noticed front brakes were frozen so backed brakes off till they spun free, it moved a little more so tomorrow am going to try backing off on the back and see what happens

stumpnc · 09-08-2017, 05:37 PM

Mike open up the air filter and check all intake ducting for any rodent nests. Rodents will eat through filters and build nests in intake ducting and when it breaks loose usually catastrophic issues occur with turbo etc.
When you shift from N to D do you feel it engage? Does it engage like it does in reverse? Have you built enough air pressure for brakes to release? If it has drum brakes they can stick to the drums when have been sitting long and sometimes you have to smack the shoes with a hammer to knock them loose from the drums. Chock wheels,build air pressure and release brakes You shoud see them move away from the drums,If ones hanging up smack it with a Big hammer.
Th e6V92 and 4 speed are not torque monsters,it takes a lot of throttle to get it all rolling. reverse is a lot lower than low forward gear is.

Mikedriggers · 09-08-2017, 07:02 PM

A lot of good info.. thanks a bunch. It does engage well in D and R and air pressure in not a problem. I'll check the air filter.

Thank you stumpnc

dmurdock · 09-08-2017, 09:29 PM

Remember it's not a pickup..don't go rockin between D and R or you'll pop a tooth in the rear end.

stumpnc · 09-09-2017, 06:31 AM

Mike when I pull my coach up on the leveling blocks in my backyard I have to almost floor it to get it up on them.
The 6V92 is a great engine But you need to be aware it does have some things you need to do DO NOT USE ANY MULTIGRADE OIL in it. The 6V92 Has to have a low ash oil. I use DELO 100 Straight 40 Wt. You cannot just buy it at the auto parts store. Oreilly's can get it overnight. Part number CHV 100-40-1
3 1 Gallon jugs to a case.Keep a few extra gallons in you coach for make up oil in between changes. Here is a great site with lots of oil information on 2 stroke Detroits
Tejas Coach Works Technical Data Page
DELO 400 does not meet spec! Do Not use it. This is what you will find in auto parts stores.
The engine holds about 6 gallons

Also Mike I see you changed the trans fluid. I hope you used the correct fluid. Dextron II -C4 or Transynd or the equivalent of dextron II
Allison HT 740 Transmission Specification | Allison HT 750 Transmission Specification | We carry Allison AT 545, Allison MT 643, Allison HT 740, Allison HT750, Allison MD 3560 Automatic Transmission and many more
Another thing the 6V92 are not to be babied keep RPM's up don't lug them. The ECM will downshift for you but keep in mind when you drive these things ,A old guy told me to slam your hand in the door and drive it like you stole it and it will last you a lifetime. Keep the right oil in it

Mikedriggers · 09-09-2017, 08:12 AM

Yes I used a dextron fluid..oil wise I used Delo 15w40. This thing would break me if I had to service it very often...6 gallons of oil and 7.5 intrans fluid..lol. I had to fix an oil leak last week...cranked it and my girlfriend told me something was pouring out underneath...oil feed line broke where it was fastened to block...rusted at the bracket. Found a company online called P C Industries that had one for $40..perfect fit...

Mikedriggers · 09-09-2017, 08:30 AM

I'm assuming you have a Detroit pusher!

Jyrocharlie · 09-09-2017, 08:40 AM

that engine is supercharged, do you have a boost gauge? you may have to push the peddle farther to get it to move if its tires are in the ground some.

Mekanic · 09-09-2017, 08:45 AM

Quote:

Originally Posted by Mikedriggers

Trying to get my motorhome running to take to the lake. 6v92 Detroit pusher/Allison ht747 tranny. Been sitting up for five years and was given to me by a friend's widow. Cranks and runs great but has no power to untrack itself...acts like airbrakes are still on but jacking it up the tires spin freely. I just drained the transmission and changed the filter screen and the in line spin on filter and no change. It will back up but has no power to go forward...any suggestions is appreciated

the 6V92 is one detroits 2 stroke diesels Great engine but it is different from a 4 stroke diesel VERY Different. These 2 stroke have their torque at a much higher RPM.
Just remember these Need more rpm to do their thing.

stumpnc · 09-09-2017, 09:02 AM

Mike the 15-40 is the wrong oil you need straight 40 weight Delo 100 40 weight The 15w40 does not have the shear properties that the 2 stroke requires. These engines are way different than a 4 stroke diesel. Using the wrong spec oil can heavily increase cylinder wear and scoring low ash oil under .1 are required for them Deko 100 fits that spec at .86 Delo 400 15-40 does not.
Deli 400 for 4 strokes and Delo100 for 2 strokes.

Mikedriggers · 09-09-2017, 09:18 AM

Thsnks Mekanic.. I'll have to check...but I've had it to the floor...don't keep it there long though...worried I may be harming something

Mikedriggers · 09-09-2017, 09:22 AM

Thanks stumpnc, I'll change oild and filters when I get it to the lake. Actually going to be living in it. Won't do traveling till I have it highway worthy..new tires and mechanically sound...maybe by then I will have learned about this thing inside and out