LB7 Allison Rebuild

[brickford5]

Preface: First post here (have been reading a lot, trying to learn) and have a question. I appreciate all feedback and knowledge I can get.

Bought my 04 LB7 at an auction a few months back so I know virtually no history other then what I can see (or have been told by those more educated then I am). I do know it has a 5 stage chip, a fairly large turbo and an aftermarket downpipe. Also around 200k miles and seems to run strong (other then the sloppy feeling tranny when chipped up and on it hard - wont do again until I have this tranny thing sorted out).

Long story short, had a few tranny codes, took it to a local shop (came highly referred). TCM was bad and all is good now. Shop said that the valve body had a lot of debri in it. Also worth noting that when I changed the tranny fluid/filters when I got the truck the fluid and pan was clean.

He said I am probably at around 700hp with the mods on the truck and recommends rebuilding the tranny (thinks it was rode hard). He told me to get a kit and bring it to him and he would do the build.

I really don't want to drop anymore then $3k-3500 but if needing to wait to and save up more that is an option.

Looking for a piece of advice (and anything else thrown my way):

Pulling that HP what kit (economical yet plenty sufficient) would be recommended? Would a shift kit be a good idea as well?

 

[Awenta]

Most importantly what shop? Otherwise you might be throwing money away.

Sent from my SM-N910V using Tapatalk

 

[PureHybrid]

If he told you just to "buy a kit" and he'd build it, I'd take it elsewhere.

Was the sloppy shifts due to you changing power levels without letting the trans relearn? It is common practice to keep the biggest tune running in Tow/haul mode, and keep the lower tunes separate.

Any good shop should be willing to tear into it and see what you have wrong, rather than just suggest a full build. Maybe post a picture of the turbo setup, and take a peek at the torque converter so we have an idea too. I doubt this truck is running on a stock trans.

 

[brickford5]

Thank you for the replys. The shop is just a small local shop, the guy has been there forever and a mechanic friend referred me there but the more reading I do (and after your comments) the more I think he's not the right guy for the job.

The 'sloppy shift' (not sure if that's the best term for it) was when I punched it with the chip turned up. It didn't chirp the tires but rather felt like more of a catch in the tranny from the surge of power.

If there is a better view for the turbo please let me know.

For the torque converter, how do I get a picture of it? I am a 'nearly' complete idiot when it comes to transmissions.

 

[Burn Down]

You need to replace the signal line (the blue one with a hole in it) going to the waste gate actuator on the turbo:thumb:

There is a inspection cover in the bottom of the bell housing that you can see the converter.

 

[PureHybrid]

You need to replace the signal line (the blue one with a hole in it) going to the waste gate actuator on the turbo:thumb:

There is a inspection cover in the bottom of the bell housing that you can see the converter.

It's all good, still has the inner layer left

Looks like an s300 based turbo, not large, but it's an upgrade.

 

[Mike L.]

You won't get a good trans for 3500.00.

 

[fastpunker]

Thank you for the replys. The shop is just a small local shop, the guy has been there forever and a mechanic friend referred me there but the more reading I do (and after your comments) the more I think he's not the right guy for the job.

The 'sloppy shift' (not sure if that's the best term for it) was when I punched it with the chip turned up. It didn't chirp the tires but rather felt like more of a catch in the tranny from the surge of power.

If there is a better view for the turbo please let me know.

For the torque converter, how do I get a picture of it? I am a 'nearly' complete idiot when it comes to transmissions.

As someone else noted, to view the torque converter.. there is an inspection plate on the bottom towards the driver side of the bell housing (from part of transmission attached to the engine). Pull the plate (if there) and see what color the converter is... if it is painted any kind of color it will be an aftermarket one. the stock converter in our trucks wasn't painted, therefore is just raw metal.

As for the rebuilding of the transmission, I personally wouldn't take it to anybody else other than Mike L (commented above). He is out in California and worth the drive, I see you are in Gilbert, AZ. Mike owns http://inglewoodtransmission.com/jm/ and is one of, if not, the best at building the Allison transmission. I lived and grew up in phx so I know the shops and area... there is no one there I would trust with an Allison. I had experiences with copperhead diesel and others there, and wouldn't go back for a trans build.

Congrats on your purchase and welcome to the forum!! :hello:

 

[Chevy1925]

Brickford, your welcome to bring it by my place and i can check it out.

i would also recommend taking it to Mike for a trans rebuild. 3-3,5k isnt going to get you a trans that will hold the HP your after.

 

[SmokeShow]

And unless there's some other parts on the truck (extra fuel via larger or multiple CP3s and bigger injectors and supporting lift pump) you aren't likely making 700hp. Maybe 600rwhp but that depends on how special that turbo is (don't know of many "hotrod" turbos with a built-in wastegate). If you're still on stock fuel system, then you are probably under 600rwhp.

And don't take any of that as a knock on your truck. Even a 500rwhp truck is a blast to drive. 600, even more betterer.

 

[TheBac]

Was it a Cali truck? I was trying to figure out what that plate is on the stock turbo and why the wastegate is on the front of the exhaust housing, not the side?

Let James do an initial inspection on it. If you do need the trans redone, he will know what to do.

 

[Chevy1925]

Was it a Cali truck? I was trying to figure out what that plate is on the stock turbo and why the wastegate is on the front of the exhaust housing, not the side?

Let James do an initial inspection on it. If you do need the trans redone, he will know what to do.

It's an aftermarket turbo of some sort. I'm thinking a bd or something. The back exhaust flange is a v band and even stock Cali turbos stil used the bolt on style flange like a federal turbo

 

[brickford5]

Thanks a bunch for all the replies. I'm learning a lot on the forum and a duramax has always been my dream truck and now that I have one (and am loving it) I feel like I'm in kindergarten again.

I took a look at the torque converter and it is blue. So not stock. I've attached a pic. (and a pic of the truck)

The tranny shop I took it to was a bunch of liers and cheats. Luckily I got it out of there before they did anything but look at it (if even that and they had it 15 days). Won't be going back there. I found that the speed input sensor on the top of the trans was not plugged in and it shifts perfectly. Although I haven't gotten on it.

The truck is from Texas and was there for it's life until I picked it up (site unseen and not running because the ignition was punched, it was a big risk but seems to have paid off and I've been very happy so far).

James, I'd be more then appreciative to meet up with you and have you give it a once over. I'd love to learn more about what I have (goods and bads). I'll shoot you a PM.

Thanks again everyone.

 

[brickford5]

Also forgot, signal line is on my short list. Fortunately I know at least enough to see that one had to go. :joker:

And Mike L, thanks for your reply and I have definitely learned I was in a hellish fairytale land at that shop and thinking $2800 on a kit and $1200 for the labor they would charge would be worth the money. If it turns out I do need a rebuild I will be taking a trip to Cali (and leaving the wife at home so we can do it right and not cheap )

 

[Chevy1925]

Got your PM Brick. Looking forward to seein the rig!

 

[onebaddmaxxx]

Looks like a precision of new hampton converter. Ick

 

[Gmclbz]

Looks like a precision of new hampton converter. Ick

Yep...

 

[brickford5]

Looks like a precision of new hampton converter. Ick

Well crud. From what I've read "Ick" is right. Worse then stock?

 

[Antsdmax]

could it be an ML precision converter from what iv read these where the ducks guts a couple of years ago

 

[onebaddmaxxx]

could it be an ML precision converter from what iv read these where the ducks guts a couple of years ago

No those are a light purple color