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Evugrandtour · 01-10-2021, 02:17 PM

Hi. We are considering a coach. It’s showroom condition inside out. We have mixed opinion about the Jake brake. My concern is having the brake always on will put a lot of wear on the transmission because of the constant downshifting?

The coach has about 60k miles and the owner always had the Jake brake on.
Cat 330HP with Allison 3000

What do you RV pros think? :P

saddlesore · 01-10-2021, 02:21 PM

I would not worry about it at all.
Just do a complete fluid change on the whole coach and then go have fun!

deblas · 01-10-2021, 03:18 PM

I would not be particularly concerned with the trans.
I would actually pay special attention to the service brakes, as they would have presumably been used with less pedal pressure.
What this could lead to is a glazing of the shoes.

Do the service brakes stop appropriately, any pulling to side, squealing,etc?

Not sure of the year, but while it may look pretty, do you have service records?

Lastly, if you are concerned about the trans, maybe you could work with seller to obtain fluid samples? There are many companies out there that will provide this analysis for you.

If you get that far, hell,
I’d take samples of engine and generator oil, trans fluid, engine and generator coolant.

That couple hundred bucks could buy you some sound sleep!

deblas · 01-10-2021, 03:21 PM

Oh and it being a Cat330/Allison combo, you’ll have a Pacbrake “exhaust brake”.

A Jake brake is a completely different type of system.

Good luck on your hunt!!

Evugrandtour · 01-10-2021, 03:22 PM

Quote:

Originally Posted by deblas

I would not be particularly concerned with the trans.
I would actually pay special attention to the service brakes, as they would have presumably been used with less pedal pressure.
What this could lead to is a glazing of the shoes.

Do the service brakes stop appropriately, any pulling to side, squealing,etc?

Not sure of the year, but while it may look pretty, do you have service records?

Lastly, if you are concerned about the trans, maybe you could work with seller to obtain fluid samples? There are many companies out there that will provide this analysis for you.

If you get that far, hell,
I’d take samples of engine and generator oil, trans fluid, engine and generator coolant.

That couple hundred bucks could buy you some sound sleep!

Hi. It is a 1 owner and the owner spend ~$600 annually at “Quinncat” a CAT repair store to change out the fluid. All service record. I pulled and check and smelled the fluid it looks and smelled nicely. I will come back with a response after test driving it and will post reply. Thank you very much.

Evugrandtour · 01-10-2021, 03:24 PM

Quote:

Originally Posted by deblas

Oh and it being a Cat330/Allison combo, you’ll have a Pacbrake “exhaust brake”.

A Jake brake is a completely different type of system.

Good luck on your hunt!!

Can you save me some googling and let me know if Pacbrake wear out trans?

deblas · 01-10-2021, 03:28 PM

It does work in conjunction with the Allison, downshifting to the next available gear within its parameters.

Basically it works as you originally described, no changes there.

I just wanted you to be familiar with vernacular of what you were looking at.

Dennis58 · 01-10-2021, 04:03 PM

Cat 330HP with Allison 3000 and 60K for miles, I see no issues here.

Skip426 · 01-10-2021, 04:20 PM

Quote:

Originally Posted by Evugrandtour

Can you save me some googling and let me know if Pacbrake wear out trans?

OK , to clear up some confusion .

Jacobs , manufactures compression ( engine ) brakes and exhaust brakes.
Jake Brake , mostly refers to compression brakes . But if someone sees the tag on the side of their Jacobs exhaust brake , then they refer to it as a Jake brake , hence the confusion .
My Cat 3126B has a, Jacobs , exhaust brake , 93,000 miles and an Allison 3000 series trans . No issues .

If Allison thought for an INSTANT that having a compression or exhaust brake on the engine could harm their transmissions, due to extra shifting , or in any way , they would issue warnings about it. They don't .

Old-Biscuit · 01-10-2021, 05:05 PM

YES...would not be a concern

Use it or Loose it (they can bindup from lack of use)

Dutch Star Don · 01-10-2021, 05:23 PM

Quote:

Originally Posted by Evugrandtour

Hi. We are considering a coach. It’s showroom condition inside out. We have mixed opinion about the Jake brake. My concern is having the brake always on will put a lot of wear on the transmission because of the constant downshifting?

The coach has about 60k miles and the owner always had the Jake brake on.
Cat 330HP with Allison 3000

What do you RV pros think? :P

Your question is a little confusing. Are you familiar with how the engine brakes and exhaust brakes work? They're not always on as in actually operating. If the previous owner used the exhaust brake, it was only when they were slowing the coach.....which is the intended design and USE of the brake. In a 500 mile travel day, the engine/exhaust brake may only be used (OPERATED) for a few minutes. How do you know how often the previous owner used it?

Even if the engine/exhaust brake wasn't used, the coach is still going to upshift and downshift as you accelerate and decelerate.

Soooo....using the engine/exhaust brake will have no real impact on the transmission.

Lastly, if you buy the coach, experiment with the exhaust brake and get use to how it works. They're not as powerful as an engine break, but if used properly, can help you keep your speed under control on a grade. The way to learn is to try different speeds on similar grades and see what breaking power it provides. You'll figure it out pretty quick. They use stop operating under 15 mph.

bneiva · 01-10-2021, 07:07 PM

Allison is one tough transmission and I seriously doubt the constant downshifting would hurt it. But I hope the prior owner kept a "fuel mileage" log because you will now find a big difference, to your benefit!

Mile Marker 42 · 01-10-2021, 07:17 PM

Quote:

Originally Posted by Evugrandtour

Hi. We are considering a coach. It’s showroom condition inside out. We have mixed opinion about the Jake brake. My concern is having the brake always on will put a lot of wear on the transmission because of the constant downshifting?

The coach has about 60k miles and the owner always had the Jake brake on.
Cat 330HP with Allison 3000

What do you RV pros think? :P

What year is the Coach? Pacbrake upgraded their product. Mine was stuck open when I bought my coach used, and I replaced it with their newer version. They recommend using their oil to lubricate it frequently. Change the trans fluid to transend? fluid and never think about it again.

Argosy · 01-11-2021, 04:40 AM

Mine was also stuck open when I got it, along with other "changes" to attempt to make it work. I've searched and researched a lot, one post I saw was from a retired Pacbrake distrubutor/installer. He said leave it on and keep it lubricated so it always moves to save yourself problems.

As he retired and wasn't sued into bankruptcy by irate customers who had to rebuild transmissions that seemed to be logical advice.