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Topic: Jake Brake Performance with Modifications (Read 701 times) previous topic - next topic

Jake Brake Performance with Modifications

In an earlier thread we discussed the merits of a preselect of 5th gear rather than 4th. I had mine changed and liked the results. After getting that done I had my single speed (all six cylinders) changed to a two speed. Now I have the choice of using three or six cylinders. With the 5th preselect and the two speed the Jake is much more usable. Still not as good as a retarder but getting close. Using the low setting (3 cylinders) on long easy grades at high speed (55 to 60) works great. If it's not enough, either drop down to 4th or change to high (6 cylinders) in 5th. I've only got about 300 miles using this setup but I had lots of hills so I think I have a pretty good handle on how to use it. Anyhow, I would recommend that anyone with a Jake change to 5th pre and make it a two speed.

In order to make the change, Cummins used one of the extra wires that runs from the dash to the rear of the coach.

Here's the switch we used. The middle is off. I switch on the rocker labeled "retarder" and leave it on. This turns on the Jake system but does not activate it. Then I use the new switch to select either low or high.
jor
93 225
95 300
97 270
99 320

Re: Jake Brake Performance with Modifications

Reply #1 –
John,

Since you've had both, what is your preference retarder or jake?  I'm assuming you have an actual Jake brake and not an exhaust brake.

Chuck
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Jake Brake Performance with Modifications

Reply #2 –
Chuck,
  It's a Jake, not and exhaust brake. Comparing the two, the retarder takes the prize. Just so easy to use. Also, it's no contest when it comes to an emergency stop. I still can't believe how that 320 would halt. That combination of discs, ABS and retarder is something else.
jor
93 225
95 300
97 270
99 320

Re: Jake Brake Performance with Modifications

Reply #3 –
You got the part number on that switch?
So you turn it on with the other switch, then go low or high?
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT

Re: Jake Brake Performance with Modifications

Reply #4 –
John, I'll say this, the retarder on your ex 320 with the 4 series trans is much more powerful than in my coach with the 3 Allison.  Thanks for the comparison, I was wondering about it, seems like an advantage to the Jake is no heat management, right? 

Chuck
"Not so  long ago we were a nation of risk takers, riding five million pounds of  thrust straight into space."  Joe Gresh
Chuck Pearson
1996 U295
2018 Can Am X3 TurboRS

Re: Jake Brake Performance with Modifications

Reply #5 –
Dave, I could have predicted you would be asking for the part number.... :-)
Tim Fiedler    2025 LTV Unity MBL on Order
2000 Chevy Tracker 2 Door Convertible 4WD Now lifted 4.5"
1985 Citroen 2CV6 Charleston
Murphy Rebel on wheels with 175HP Titan
Cessna P337
1980 48' Westport MY (!/4 Share)

Re: Jake Brake Performance with Modifications

Reply #6 –
Quote
seems like an advantage to the Jake is no heat management, right? 
Chuck, yes, no issue with heat using the Jake. The retarder heats up that fluid but in my experience I never approached the 4060's upper heat limit. Pretty much a non issue.

Dave, I'll get you the part number(s). It's actually a combo of two switches with the one you see slipped into the frame of one that would fit perfectly into the factory cutout. The visible one was $46 and the other, $13.
jor
93 225
95 300
97 270
99 320

Re: Jake Brake Performance with Modifications

Reply #7 –
It may just be my  inexperience regarding driving these rigs, but I have yet to feel the need for more braking power from the retarder on our 3 series tranny. In fact, putting back to the furthest position while on the highway would likely clear your countertops, if you neglected to do it before leaving :o
Don
Quote from: Chuck Pearson –
John, I'll say this, the retarder on your ex 320 with the 4 series trans is much more powerful than in my coach with the 3 Allison.  Thanks for the comparison, I was wondering about it, seems like an advantage to the Jake is no heat management, right? 

Chuck
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Don & Tys
1999 U270 3602 WTFE #5402
Xtreme Stage 1 w/Headlight, Step Conversion, etc.
2009 Honda Fit Sport with Navi
Freedom is NOT "just another word for nothing left to lose"... with apologies to Kris Kristofferson

Re: Jake Brake Performance with Modifications

Reply #8 –
Quote from: acousticart –
It may just be my  inexperience regarding driving these rigs, but I have to feel the need for more braking power from the retarder on our 3 series tranny. In fact, putting back to the furthest position while on the highway would likely clear your countertops, if you neglected to do it before leaving :o
Don
That's why you don't use it when the roads are wet or slippery :o
1994 U225
build #4514

Re: Jake Brake Performance with Modifications

Reply #9 –
On my 36 u320 the full retarder felt like the service brakes coming from my 270.  Still they both work well. 
2025 Wanderbox Outpost 32 on F600 Expedition Motorhome
2015 Born Free Royal Splendor on Ford 550 nonslide version  for sale
Former Coaches  covering. 360,000 miles
1999 34 U270
2000 36 U320
2001 42' double slide U320
2018 Jeep Rubicon

Re: Jake Brake Performance with Modifications

Reply #10 –
I don't have experience with a Jake, but I can say I'm really thankful for the retarder in our U320. It is quiet, it works extremely well, it really saves the service brakes and I need to pay attention to the transmission temperature only on extremely long, extremely steep grades. I would definitely not want to be without it!
David and Carolyn Osborn
1995 U320C SE 40' Build 4726 Feb 1995
FMCA 147762
Motorcade 17186

Re: Jake Brake Performance with Modifications

Reply #11 –
Quote
You got the part number on that switch?
Dave,
  Here are the three part numbers. Cummins had the first two in stock. The third one is the red switch; they got that one from Monaco.
jor



93 225
95 300
97 270
99 320

Re: Jake Brake Performance with Modifications

Reply #12 –
Awesome - Monaco switch ordered through Veurinks RV center in Michigan - Monaco Direct Parts Warehouse | VeurinksRV.com in Grand Rapids, Michigan

Posted to them online - they called me in less than 10 minutes.
The selected media item is not currently available. Dave Head & Megan Westbrook
Titusville, FL - The Great Outdoors
'98 270 buying this month
Toad is a 2018 F150 XLT