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Old 17-10-2015, 09:38   #16
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Re: trans off 4-71 detroit D help

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Old 17-10-2015, 09:44   #17
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Re: trans off 4-71 detroit D help

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Old 17-10-2015, 10:06   #18
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Re: trans off 4-71 detroit D help

Sounds like the spud shaft has rusted to the flex plate. Use force and replace the flex plate.

P
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Old 17-10-2015, 11:34   #19
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Re: trans off 4-71 detroit D help

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Originally Posted by captain58sailin View Post
If it is a twin disc reduction gear, it has a different drive method.
Thanks for your reply and yes it may be a diffrent drive .i was told about a tooth ring that is pressed into the flywheel and the box has three meshing cogs simiular to a planetary drive . But i am not saying that is what it is but i gotta look at the options and info of how to break this open or if there is a secret to the job .like cracking a safe
Ok i will post a photo and see if anyone recognizes it .its 330am so i will do that after the zzz cheers
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Old 17-10-2015, 11:48   #20
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Re: trans off 4-71 detroit D help

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Originally Posted by jeepdoesrubicon View Post
Sounds like the spud shaft has rusted to the flex plate. Use force and replace the flex plate.

P
At the end of the day that is the only option i think !

Ok thank you all heaps for your input .and i will take the above as encouragement as it must come off .
But still that flex plate must flex to break

O lord help me i will let you know what happens
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Old 17-10-2015, 11:49   #21
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Re: trans off 4-71 detroit D help

On your bell housing (between your motor and transmission) when you look in the direction of the motor you should be able to view an access hole to reach the bolts that hold the flex plate to your flywheel. Turn the motor over by hand to be able to reach these bolts individually. Remove them and the transmission I should be free to slide out. If you cannot find this take a picture and send it to me...
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Old 17-10-2015, 12:08   #22
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Re: trans off 4-71 detroit D help

I run a 3-71 Detroit in a very old work boat. It uses a Paragon HJ6 hydraulic transmission with 2:1 gear reduction.
There is nothing special about mounting the transmission on a 71 except it is heavy.
The transmission simply bolts to the flywheel cover, the transmission is driven by a splined input shaft from torque disk bolted to the engine flywheel. It could also have some adapter rings to mate to the transmission bolt pattern.
If the engine has been submerged in sea water it is probably a rusty mess.
Is the engine a modern turbocharged innercooled engine or is an antique like ours. I like the old engine but it does run smokey,
How do you know the cam is seized, on a detroit the gear train to drive the cam and balance shaft are always on the front of the engine under the gear cover. Take the inspection covers off the opposite side side from the blower and check to see if the pistons are badly seized in the bores, pistons can be viewed via the intake slots in the liners.
I recommend you get a set of service manuals for everything you have.
Ebay is a good place to start looking.
Don't know where you are but technical support is getting harder to find every year, but it is a simple machine and I have always maintained ours and parts support is still good.
Boatdiesel.com has a detroit section with several knowledgeable supporters.
Good luck with the old detroit, cast iron monster engine.
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Old 17-10-2015, 12:10   #23
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Re: trans off 4-71 detroit D help

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Originally Posted by seabreez View Post
On your bell housing (between your motor and transmission) when you look in the direction of the motor you should be able to view an access hole to reach the bolts that hold the flex plate to your flywheel. Turn the motor over by hand to be able to reach these bolts individually. Remove them and the transmission I should be free to slide out. If you cannot find this take a picture and send it to me...
I wish there was a cover but i know what your saying ..the only accsses is via the starter gear to get my little finger in is BS so no spanner can get there . Last week i thought i had it worked out . As there is a 1inch plug on the engine side of the flywheel housing but i turned the engine and there is no bolts through the flywheel holding the flexplate . As this engine is possibly early 70s what would the flex plate be made of
I have seen them on bobcat loader engines and i think teflon and that strong s*** t so did they have that back in the day of 4-71s

Thanks i will put a pick up tomorow i need zzz
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Old 17-10-2015, 12:24   #24
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Re: trans off 4-71 detroit D help

I run a 3-71 Detroit in a very old work boat. It uses a Paragon HJ6 hydraulic transmission with 2:1 gear reduction.
There is nothing special about mounting the transmission on a 71 except it is heavy.
The transmission simply bolts to the flywheel cover, the transmission is driven by a splined input shaft from torque disk bolted to the engine flywheel. It could also have some adapter rings to mate to the transmission bolt pattern.
If the engine has been submerged in sea water it is probably a rusty mess.
Is the engine a modern turbocharged innercooled engine or is an antique like ours. I like the old engine but it does run smokey,
How do you know the cam is seized, on a detroit the gear train to drive the cam and balance shaft are always on the front of the engine under the gear cover. Take the inspection covers off the opposite side side from the blower and check to see if the pistons are badly seized in the bores, pistons can be viewed via the intake slots in the liners.
I recommend you get a set of service manuals for everything you have.
Ebay is a good place to start looking.
Don't know where you are but technical support is getting harder to find every year, but it is a simple machine and I have always maintained ours and parts support is still good.
Boatdiesel.com has a detroit section with several knowledgeable supporters.
Good luck with the old detroit, cast iron monster engine.
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Old 17-10-2015, 12:55   #25
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Re: trans off 4-71 detroit D help

Think Twin Disc or possibly ZF. Maybe one of the larger Borg-Warners for a 4-71, but unlikely. There may be drawings or parts catalogs online for those trannys; surf around for them to help identify yours.

Just an idea, but is there an inspection cover on the bell housing or f/w hsg that will let you get to bolts holding the f/w and flex plate together?
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Old 17-10-2015, 16:43   #26
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Re: Trans Off 4-71 Detroit D - Help

As previously stated, your transmission input shaft is most likely rusted to the drive disk. You would be very wise to pay for a diesel mechanic to determine the problem. You can do some expensive damage if you start driving wedges into parts, a mechanic will tell you what to do. Maybe even guide you in fixing your engine. Detroits are great engines.
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Old 18-10-2015, 03:23   #27
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Re: trans off 4-71 detroit D help

Thanks for your input and i love that everyone cares the following link is a pic of the reduction box i have hope to find what the brand it is . The engine is a 4-71 Detroit Diesel cheers everyone

ttps://ci5.googleusercontent.com/proxy/-lyVWgu6_dxfqnTsA5he43t4Z3gffhcett-AbSkFtNtO_sqzP8OUjwex-Sw2AfmPXMgjT9fnilspTd5ny0FDVMVuqxa2JF6btJlaUi8CESg fgA342N_G=s0-d-e1-ft#http://i.ebayimg.com/00/s/OTYwWDE2MDA=/z/CIsAAOSwwbdWIuT7/$_8.JPG
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Old 18-10-2015, 03:40   #28
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Re: Trans Off 4-71 Detroit D - Help

Its not your camshaft anyway most likely stuck valve stems or pistons...lube them up and smack them with dead blow hammer and see if it turns...just a thought....been through that before when i left a boat sitting for a year or so....plus it has low hours ...theres a chance u dont have to overhaul it
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Old 18-10-2015, 03:56   #29
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Re: Trans Off 4-71 Detroit D - Help

and if it was swamped ..do you have a new starter and stuff??? replace all the fluids?? how are u trying to turn the engine???
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Old 18-10-2015, 07:36   #30
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Re: Trans Off 4-71 Detroit D - Help

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and if it was swamped ..do you have a new starter and stuff??? replace all the fluids?? how are u trying to turn the engine???
Thanks for your help capt ric ..but i have the moter down bare and have tapzped the cam through to release the timing gear now the flywheel will move . The problem now is to break the flexdrive plate off the flywheel as the gearbox is not coming off .
Why. i am convinced its corrosion .on the shaft that goes through the plate . Once i get that off i can realease the cam gear out of the fly housing then the cam retainig housing that i got to get to as the keyway lock is still in place as the cam won't go any further but it went enough to turn the beast
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