Towing Transmission Question

[Airman68]

Wow, this is a lot of great information! I think first I have to find out exactly which transmission I have and what the drive ratio is. Was ther eonly 1 4spd option in '08? Second, I dont have a trans cooler that I'm aware of. I know this topic has been covered but would that be a good idea? As far as the tune is concerned, is there a good out of the box option or is this more of a custom thing? I guess my boat will be the next thing towed this summer, about #3500. I am looking at bigger boats closer to #5000 so it will be good to work on this issue.

 

[NickTransmissions]

Wow, this is a lot of great information! I think first I have to find out exactly which transmission I have and what the drive ratio is. Was ther eonly 1 4spd option in '08? Second, I dont have a trans cooler that I'm aware of. I know this topic has been covered but would that be a good idea? As far as the tune is concerned, is there a good out of the box option or is this more of a custom thing? I guess my boat will be the next thing towed this summer, about #3500. I am looking at bigger boats closer to #5000 so it will be good to work on this issue.

You have either a 4l60 or 6l80, depending on engine size (4.8/5.3= 4l60 while 6.0= 6l80). You can call a gm dealer, ask for parts and give them the last 8 digits of your vin and they can tell you what trans and ratio you should have…Alternatively, you can crawl underneath, take a pic of the pan and post it. Square-shaped and 16 13mm bolts, its a 4l60 or 70; more rectangular and 18 10mm bolts, its a 6L80e. I think some info such as RPO codes should be on the driver side door or door frame as well.

Quick google search tells me you should have a 4l60e but confirm…

 

[Marky Dissod]

Check the SPID sticker in the glovebox.
M30 = 4L60E
M32 = 4L65E
MN8 = 4L80E
MYC = 6L80E

 

[Airman68]

Thanks for the info. My truck is in my storage barn right now. I'll take a look in the next couple days. I pull it out full time for summer in the next couple weeks when I get my boat out of storage.

 

[tdebacker]

If it makes you feel better, I towed my 1982 K10 on my 20' trailer, and it pulled the same as it did without the truck.

I think when you put any trailer behind us, it'll feel like it's bogged down, but it'll feel almost the same whether it's 1500 pounds or 7000 pounds.

 

[Marky Dissod]

Check the SPID sticker in the glovebox.
MD8 = 700R4 / 4L60 (no 'E')
M30 = 4L60E
M32 = 4L65E (Heavy Duty)
M70 = 4L70E (Super Duty)

MT1 = 4L80E
MN8 = 4L85E (Heavy Duty)

MYC = 6L80E
MYD = 6L90E (Heavy Duty)

M5Q
M5U
M5X
MQE = 8L90E (depends on what year and what features)

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