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Topic: U300 3176B Retarder or Jake (Read 991 times) previous topic - next topic

U300 3176B Retarder or Jake

Need some clarity, Ive looked at several posts and now I'm not sure if I have a trans retarder or Jake. Dash has retarder switch. Looked at the transmission housing rear and it does not look to have trans retard, Im confused..!!

Thanks,Hans
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)

Re: U300 3176B Retarder or Jake

Reply #1 –
Detroit engine = Jake Brake  Cummins  =  Retarder  most of the time / Also 6 speed allison = retarder  4 speed allison = Jake
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Gerry & Brenda
CHARLOTTE HARBOR, FL
1994 Grand Villa - # 4466
U300 Unihome - 6V92 Detroit
4 speed Allison - Jake Brake

Re: U300 3176B Retarder or Jake

Reply #2 –
The Caterpillar 3176B CAN be equipped with then engine compression brake.

You could call the Caterpillar RV Hotline with your engine serial number to see if yours was so equipped: 877 777-3126.

So, it was really up to how that coach was speced, as you could do either a transmission retarder OR engine compression brake.

Brett
Brett Wolfe
EX: 1993 U240
Moderator, ForeForum 2001-
Moderator Diesel RV Club 2002-
Moderator, FMCA Forum 2009-2020
Chairman FMCA Technical Advisory Committee 2011-2020

Re: U300 3176B Retarder or Jake

Reply #3 –
Hans,
Lift up the bed and look at the passenger side of the head below the valve cover. This would be the Jake brake housing and it has big cast embossed letters on the side. I think the letters spell out JACOBS
Take a look, I had some pictures at one time but can't find them
Good luck,
Rick
Rick

Re: U300 3176B Retarder or Jake

Reply #4 –
A Retarder is an auxiliary braking device. You can call Foretravel or your engine manufacturer. They can tell you what was ordered.

There was a coach at MOT that a previous owner had installed a jake after the trans retarder failed.
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: U300 3176B Retarder or Jake

Reply #5 –
Quote from: sfbmw –
Need some clarity, Ive looked at several posts and now I'm not sure if I have a trans retarder or Jake. Dash has retarder switch. Looked at the transmission housing rear and it does not look to have trans retard, Im confused..!!

Thanks,Hans

Looking at the specs, your 6 speed Allison does not or at least should not have a retarder but the Cat does have a Jake. You should be able to tell the difference with the driver's window open when you start braking. Not noisy enough that you can't use it in residential areas. All the dash switches I have seen say retarder whether a trans retarder or Jake brake.

Earlier U300s through 1991 had the 748 four speed with a trans retarder while 1992 and up U300s had the 746 four speed with a Jake on the Detroit. 

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)

Re: U300 3176B Retarder or Jake

Reply #6 –
Quote
Earlier U300s through 1991 had the 748 four speed with a trans retarder
Actually the transmission is the smaller 648 four speed with retarder (300 hp engine).  Post '91 needed the larger tranny since engine went to 350 hp.
This is just speculation on my part but I would guess Foretravel switched from retarder to Jake in '92 because of the increased length of the 700 series transmission.  It maybe that the driveshaft would be too short to work if they added the retarder.  Driveshaft length can be an issue with diesel pushers sometimes in order to keep the universal joints within the angular limits.  This is one of the reasons to keep your ride height within spec so the universal joint angle doesn't become too severe.
John Fitzgerald
1991 U300 (SAI) Side Aisle Island Bed 40'
Detroit 6V92 with Allison Retarder
Meridian (Boise), Idaho

Re: U300 3176B Retarder or Jake

Reply #7 –
My 1995 U300 with the Cat has the Jake Brake. I've attached a picture of the cylinder head  as Rick described.
Michael
1995 U300SE CAT 3176B Build # 4612 ("Marvin")

Re: U300 3176B Retarder or Jake

Reply #8 –
I was told by one of the old Foretravel techs that the Detroit 6V92, 350 hp had too much torque for the 6 speed transmission and  retarder available at that time. Was there retarders on the four speed Allisons? I was under the impression that retarders were only on the six speed transmissions.
The selected media item is not currently available.Kent Speers
Locust Grove, OK
1993 U300 SSE 40' (Restored at FOT 2009) Build 4323
720 watts Solar
6V92TA DDEC Silver Engine
2014 Subaru Outback

Re: U300 3176B Retarder or Jake

Reply #9 –
Thank You all for the response, lifted the bed today and verified it does have a Jake Brake as per Rick and Geomm
Hans & Marjet
1995 U300 "Ben" (#4719)
3176B Cat,4060HD,Jake
SKP#139131
Motorcade#17579
2006 Honda Element (towed)
 

Re: U300 3176B Retarder or Jake

Reply #10 –
Kent,

Here is the link to the spec page for the 1991 U300. Earlier U300s are listed with the same retarder instead of Jake. In my last post, I typed a 7 but it is an Allison MTB 648 with retarder in any U300 older than 1992. 1991 Foretravel U300 Specifications They probably bought tons of switches for the dash so that's the reason the later models still have the word retarder on the switch I guess.
 
In the Foretravel manuals our coach came with, the transmission is listed as a 747 not a 746 so I guess I will have to take a look at the plate on the trans.

Pierce
Pierce and Gaylie Stewart
'93 U300/36 WTBI
Detroit 6V-92TA Jake
1140 watts on the roof
SBFD (ret)