LB7: Year Differences

Dura-Ration

You Shoulda GotA Diesel
Jun 20, 2008
128
0
0
64
Escatawpa, Ms.
What is the differences of 01-02 and 03-05 transmissions ? Can you put an 03-05 trans in a 01-02 truck ? And if so is there any changes to make in efi live? Sorry if this as been asked before. Thanks
 

dmaxfireman

'Can do' kind of guy
Apr 8, 2007
2,329
1
38
CT
yes you can interchange tranny's. you should try to get an '01 tcm file and flash it into the tcm. i have an 06 so its different but i hear the 01 os is the best.
 

duratothemax

<--- slippery roads
Aug 27, 2006
7,139
4
0
Wyoming
What is the differences of 01-02 and 03-05 transmissions ? Can you put an 03-05 trans in a 01-02 truck ? And if so is there any changes to make in efi live? Sorry if this as been asked before. Thanks

couple things...kinda confusing. Mike, correct me if I mixed any of this up:

01-02 trucks have a unique bellhousing and cooler fittings.

03-05 have the same bellhousing.

03-04 have unique cooler fittings that will not work with 01-02 Allisons, or 04.5+ allisons

You CAN use an 03-04 bellhousing in an LLY truck IF you swap the cooler fittings on the bellhousing.

01-02 have a different thread size on the belhousing for the cooler fittings. You can not use 03-04 or 04.5-05 fittings in an 01-02 bellhousing

LLY cooler fitings WILL NOT FIT into an 01-02 bellhousing. 03-04 LB7 allisons have the same bellhousing as the LLY Allisons, but different cooler fittings.

01-03 allisons dont have the G-solenoid in the valve body
04+ allisons have the G-solenoid. There is an exception...All LLY's have the G-solenoid, SOME 2004 LB7's had the G-solenoid (but it didnt do anything). Probably just an overlap in production; Allison started making the LLY valvebodies with the G-solenoid a bit early and decided to throw some extras into the last of the LB7's.

You can use an LLY valvebody (with the G-solenoid) in any 01-04 LB7 allison without problems. You can use an 01-04 LB7 valvebody in an LLY, but you might get a check engine light/set a code unless you reflash the TCM with an 01-03 Operating system (that does not ahve the G-solenoid enabled)

WOW...that was a mouthful. I probably mixed at least some of that up...wait for mike to give the definitive answer.

Ben
 

duratothemax

<--- slippery roads
Aug 27, 2006
7,139
4
0
Wyoming
Dura-ration, to answer your question directly,

Yes, you can use an 03-05 trans in your truck, BUT you will have to swap bellhousings.
 

dmaxfireman

'Can do' kind of guy
Apr 8, 2007
2,329
1
38
CT
woah talk about some serious tech knowledge ben :D how the beck do you remember all this stuff?? you should see my bookmarks all stuff i wish i could remember but have to reference all the time
 
Last edited:

Dura-Ration

You Shoulda GotA Diesel
Jun 20, 2008
128
0
0
64
Escatawpa, Ms.
Great

Thank you Duratothemax for the definitive answers to my questions. What I was thinking to do is buy a junk yard transmission to rebuild while I continue to drive my truck. It sounds like I need to find an 01 or 02 trans. I don't need more work. Thanks MikeL for your added answer as well.
 

Mike L.

Got Sheep?
Staff member
Vendor/Sponsor
Aug 12, 2006
15,686
231
63
Fullerton CA
Hmmm... Its clear that I don't know a damn thing about much of anything really... I'll relinquish my posting priveledges until I reach a state of higher knowledge.

There are more things I don't know about the Allison than I do know. I just keep trying to learn.:D
 

sweetdiesel

That's better
Aug 6, 2006
10,390
0
0
50
Thailand
My 05 runs a 01 and my 01 runs a 05


They can be swapped you just need Mike on standby:D

I wish there was a way to keep the larger coolant lines and ORB fittings from the 05
 

SmokeShow

Well-known member
Nov 30, 2006
6,814
32
48
41
Lawrenceburg, KY
oh man, I hope this bellhousing I bought for "a 5-spd allison" will work in my 02. Nervous now...

If I take a picture of it, can someone tell if it'll work or not?


Thanks
 

sweetdiesel

That's better
Aug 6, 2006
10,390
0
0
50
Thailand
oh man, I hope this bellhousing I bought for "a 5-spd allison" will work in my 02. Nervous now...

If I take a picture of it, can someone tell if it'll work or not?


Thanks

Maybe just measure the ID of the holes for the cooler lines ( remove the ORB fitting first )
 

Dura-Ration

You Shoulda GotA Diesel
Jun 20, 2008
128
0
0
64
Escatawpa, Ms.
Whoa

I went to price some junk yard transmissions today and they wanted gold for them. 1100 to 1500 for a trans that nobody knew what condition it was in when it was removed! Whoa. Is this about the price for one?
 

sweetdiesel

That's better
Aug 6, 2006
10,390
0
0
50
Thailand
I went to price some junk yard transmissions today and they wanted gold for them. 1100 to 1500 for a trans that nobody knew what condition it was in when it was removed! Whoa. Is this about the price for one?

Seems a little steep to me? But keep in mind if you find a trans for say 600.00 you still have to ship it and that is costly

Unless you can drive and pick it up
 

FMOS

Hard Up
Nov 18, 2008
352
0
0
Fort McMurray, Alberta, Canada
Something I do know!

I looked around Alberta, and the going rate for an allison core was 1000 bucks, regardless of condition.

I imagine since your in the states it would be a bit cheaper.
 

SmokeShow

Well-known member
Nov 30, 2006
6,814
32
48
41
Lawrenceburg, KY
As best as I could measure with a tape measure, the distance across the threads of the hole "to cooler" is about 13/16" or maybe 7/8". There was no fitting in it.

There was a fitting in the hole "from cooler" and the threads measured the same as above. The hole in the fitting was pretty close 5/8" on the small side and more like 13/16" where the cooler line plugs in and locks.



Do these measurements help anyone help me decide which bell I have. :beer
 

THEFERMANATOR

LEGALLY INSANE
Feb 16, 2009
3,887
38
48
41
ZEPHYRHILLS, FL
I know that the 01-02 bellhousings use an -8 AN size going into the bellhousing for both to and from, and the 03 fitting they got me at the dealership by mistake were -10's. I know the 01-02's are -8 internal O-ring fitting as the steel lines wouldn't fit mine so I went with braided hose instead and had to get -8 to -10 unions and make a custom -8 O-ring to -10 flared to hook-up my lines. My new radiator which uses the newer fittings(my 01 fittings wouldn't thread into it) are a -10 O-ring, same as the 03+ external tranny coolers thread size. GM makes adapter fittings that will allow an 03 bellhousing to hook-up directly to the 01-02 lines with no modifications.

-8 3/4X16
-10 7/8X14
 
Last edited: