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11-25-2012, 05:35 PM
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#1
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Member
Join Date: Jul 2012
Location: Brandon, Fl
Posts: 71
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F 250 Super Duty downshift bang
On our way home from our Thanksgiving camping trip when slowing down in tow haul mode there was a loud bang and lurch of the rig. It happened four times in the last two hundred miles, I finally switched it out of tow haul mode and it did not happen again. Here is the set up, a Ford F 250 Super Duty Diesel. 2008 pulling a 2008 Cardinal 30Rk, weighs about 13,000. The common factor was that I was slowing down pretty slowly to a light and when the trany down shifted from 3rd gear to second (I think) There was a loud bang and lurch of the truck, the first time it happened I thought we had been hit, the second time I thought my transmission and fallen out. Any ideas?
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11-25-2012, 06:13 PM
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#3
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Senior Member
Join Date: Mar 2012
Posts: 1,137
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Some newer F150's had the same problem. The splines on the driveshaft needed to be greased - because they had no grease at all!!
F150's have a TSB (technical service bulletin)
I suggest that you search for TSB's for the year and model of you truck.
This might help
http://www.ford-trucks.com/tsb/fulltext/index.php
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FOR SALE 2014 BOSS 6.2L F350
2012 Surveyor SV264
NW Oregon
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11-25-2012, 06:52 PM
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#4
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Senior Member
Join Date: Sep 2011
Location: Komoka Ontario
Posts: 2,680
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Some of the fords had a problem with the torque converter failing to unlock!
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11-25-2012, 09:11 PM
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#5
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Member
Join Date: Jul 2012
Location: Brandon, Fl
Posts: 71
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thanks twisty checking it out
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11-25-2012, 09:20 PM
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#6
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Senior Member
Join Date: Jun 2012
Location: Texas
Posts: 154
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Quote:
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Originally Posted by sor126
On our way home from our Thanksgiving camping trip when slowing down in tow haul mode there was a loud bang and lurch of the rig. It happened four times in the last two hundred miles, I finally switched it out of tow haul mode and it did not happen again. Here is the set up, a Ford F 250 Super Duty Diesel. 2008 pulling a 2008 Cardinal 30Rk, weighs about 13,000. The common factor was that I was slowing down pretty slowly to a light and when the trany down shifted from 3rd gear to second (I think) There was a loud bang and lurch of the truck, the first time it happened I thought we had been hit, the second time I thought my transmission and fallen out. Any ideas?
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Sound like transmission is going out. Ours did that after we had a chip installed and had to get a new transmission. Made it home with a line of fluid down the road got rv backed in and it just poured out. We have a 2001 f 250 diesel. Good luck
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11-25-2012, 10:17 PM
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#7
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Senior Member
Join Date: Mar 2012
Posts: 1,137
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Quote:
Originally Posted by sor126
thanks twisty checking it out
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You're welcome.
TSB's can be printed from many websites. Print what you believe is a problem and take it with you to the dealer. Many dealers are not aware of all of the TSB's.
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FOR SALE 2014 BOSS 6.2L F350
2012 Surveyor SV264
NW Oregon
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11-26-2012, 10:12 AM
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#8
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Now a "Top Member"
Join Date: Feb 2010
Location: Roman Forest, TX
Posts: 4,347
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It could be the normal operation of the transmission also. When I had my 2008, it really hammered on the downshift in tow/haul mode. Scared the bejeezus out of me the first couple of times it did it, but after that I was prepared for it. I was told it was normal, though for the life of me I couldn't understand how that much force could be good for the tranny.
Anyway, the 2011 and up sure seem to have that problem fixed. I barely knew mine was downshifting until I looked at the gear it was in and saw the RPM's jump up. It is as smooth as silk in these new trucks.
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2010 Wildcat 28RKBS
2019 Ford F-250 XLT - AWESOME Truck!
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11-27-2012, 01:31 PM
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#9
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Senior Member
Join Date: Dec 2011
Location: Country
Posts: 290
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DDC may be on to something here. In tow/haul mode, doesnt the torue converter stay locked up longer? I know that when my converter unlocks its just a coasting feeling I get but the common item is the tow mode being on. I read the Ford thread and there wasn't an answer but lots of folks are having this issue.
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Matt & Kathie
2022 Cedar Creek
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11-29-2012, 11:36 AM
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#10
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Member
Join Date: Jul 2012
Location: Brandon, Fl
Posts: 71
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Well here is an update on the Super Bang on the Super Duty. Took it to the shop and printed out all of the posts from y'all, service tech just kind of smiled and scratched his head. Well turns out that the truck did throw a code. It was for a bad brake switch. I looked at the paper work and they replaced a BPP switch and a AB Switch Assembly. We will see what happens next time I tow the rig. Thanks for everyones help this is an awesome forum. I will post next time we tow.
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11-30-2012, 12:16 PM
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#11
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Senior Member
Join Date: Dec 2011
Location: Country
Posts: 290
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Hmm. Thats kinda not what I was thinking, but I'm not a diesel mech. Post back up if this was a good fix.
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Matt & Kathie
2022 Cedar Creek
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11-30-2012, 02:39 PM
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#12
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Member
Join Date: Jul 2012
Location: Brandon, Fl
Posts: 71
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Yeah I kind of scratched my head on the solution as well. It will be a couple of weeks but I am going to road test it and see what happens. Thanks. I will post either way
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Linear Mode
