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
Detroit engine = Jake Brake Cummins = Retarder most of the time / Also 6 speed allison = retarder 4 speed allison = Jake
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
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
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.
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
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.
My 1995 U300 with the Cat has the Jake Brake. I've attached a picture of the cylinder head as Rick described.
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.
Thank You all for the response, lifted the bed today and verified it does have a Jake Brake as per Rick and Geomm
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 (http://beamalarm.com/foretravel-links/models/1991_foretravel_u300_specifications.html) 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