Trans and differentials

[08 2500 HD]

How do I know which transmissionis in my 08 2500HD 6.0L ? The GL90 or the 1000? Also how do I know which front and rear differentials I have?

[herm0016]

its probalby a 4l80e or a 6l90e. how many speed is it?

 

you should be able to use a vin decoder to find all of that info.

[dewfpo]

Only the 8.1L gassers and the Dmaxs came with Allison 1000's.

 

DEWFPO

[markw8]

6l90e.

 

Mark

[chakis24]

the glovebox will have a sticker with the RPO codes. one of them represents the rear end. i think gt4 = 3.73 and gt5 = 4.10 and gu6 = 3.42?

[08 2500 HD]

Ok Thanks. It is a 6 speed so it must be the 6190. The RPO in the glove box is GT4.

[ChevyTech77]

MYD = 6L90E trans. This is the only trans available with the 6.0l

GT4 = 3.73:1 gear ratio but does not denote what differentials you have.

 

You should have a 9.25" r.g. IFS front and 10.25" r.g. 14 bolt GM Full Floating axle rear. If you have G80 RPO code, you have a factory rear locking differential as well.

[Shatterz]

MYD = 6L90E trans. This is the only trans available with the 6.0l

GT4 = 3.73:1 gear ratio but does not denote what differentials you have.

 

You should have a 9.25" r.g. IFS front and 10.25" r.g. 14 bolt GM Full Floating axle rear. If you have G80 RPO code, you have a factory rear locking differential as well.

 

 

I'm not trying to nit pick but isn't the 14 bolt a 10.5" ring gear with the gas motor?

[08 2500 HD]

I do have the MYD code but not G80. Would it be a big job to change over to a rear locking differential?

[ChevyTech77]

MYD = 6L90E trans. This is the only trans available with the 6.0l

GT4 = 3.73:1 gear ratio but does not denote what differentials you have.

 

You should have a 9.25" r.g. IFS front and 10.25" r.g. 14 bolt GM Full Floating axle rear. If you have G80 RPO code, you have a factory rear locking differential as well.

 

 

I'm not trying to nit pick but isn't the 14 bolt a 10.5" ring gear with the gas motor?

 

You are nit picking and you are right all the 14 bolt full floater's were 10.5" r.g.'s behind the gas engines, 11.5" behind the Dmax's. Thanks. lol.

 

I do have the MYD code but not G80. Would it be a big job to change over to a rear locking differential?

 

Not worth it. By an Detroit Locker.

[dewfpo]

all the 14 bolt full floater's were 10.5" r.g.'s behind the gas engines, 11.5" behind the Dmax's.

 

I believe the 11.5"er's were standard on the 8.1L gassers as well as the Dmax's.

 

DEWFPO