need help on Allison update

bob4fixin

New member
Oct 11, 2022
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have been working on a Allison trans with 2 codes P0848 and P0751. I need info. on these what are the volts to them, wire color so on to fix this.
Fixed the P0848 code still have a P0751 code. with foot on the brake can feel the trans surge while in drive.
 
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Chevy1925

don't know sh!t about IFS
Staff member
Oct 21, 2009
21,740
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Phoenix Az
have been working on a Allison trans with 2 codes P0848 and P0751. I need info. on these what are the volts to them, wire color so on to fix this.
are you a tech, bob? what all have you done already? is this your truck or someone elses?
 

bob4fixin

New member
Oct 11, 2022
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are you a tech, bob? what all have you done already? is this your truck or someone elses?
yes have 30 years in the field. had trans rebuild at a trans shop. no it is not mine, it's a friend's. I don't work on trans more the eng. side.
 

KyleC4

Tech
Dec 30, 2016
470
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Bay Area
Trans rebuilt at another shop and you’re fixing it……? Why did the owner of the truck have another shop rebuild it ?
 

bob4fixin

New member
Oct 11, 2022
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this isnt a wiring issue. its a build issue, fluid level issue or something else internal.
I hope you are right on the build issue. the bad thing is I live on the coast and the shop which did the build is over 50 miles inland. they are going to want me to bring it to them. I'm not going to pay the tow bill. Now I know with engs. you start with the lager codes. Is it the same on trans. too.
 

juddski88

Freedom Diesel
Jul 1, 2008
4,657
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Chesterfield, Mass.
I hope you are right on the build issue. the bad thing is I live on the coast and the shop which did the build is over 50 miles inland. they are going to want me to bring it to them. I'm not going to pay the tow bill. Now I know with engs. you start with the lager codes. Is it the same on trans. too.
Where are you located?
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,224
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Larsen, Wisconsin
I hope you are right on the build issue. the bad thing is I live on the coast and the shop which did the build is over 50 miles inland. they are going to want me to bring it to them. I'm not going to pay the tow bill. Now I know with engs. you start with the lager codes. Is it the same on trans. too.
Good news, you won't have to pay the tow bill as you didn't build the trans nor is it your truck :)
 
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bob4fixin

New member
Oct 11, 2022
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Good news, you won't have to pay the tow bill as you didn't build the trans nor is it your truck :)
would like to get paid for r&r it was one of the biggest trans I have pulled, back in the day a turbo 350 is small to this giant
 

Bdsankey

Vendor
Vendor/Sponsor
Feb 1, 2018
4,224
1,326
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Larsen, Wisconsin
would like to get paid for r&r it was one of the biggest trans I have pulled, back in the day a turbo 350 is small to this giant
So you're asking us for help on someone else's built trans which needs to likely be removed (as long as fluid level was verified to be correct) but don't want to hear that solution because you want your R&R money. We're trying to help as a forum but you don't want to hear the real solution. You don't have trans building experience per this thread, you didn't build it (meaning that if you crack it open the warranty is void), but don't want to take it back over a couple hundred dollars.


Big also doesn't make it time consuming. An Allison is an extremely quick trans to remove in my opinion. The last one we did the truck came in at 3:15 and by the time the doors closed at 5 the trans was already out and the front drum was most of the way disassembled.