I have to replace the trans in my 98 silverado 5.7 4x4. If im spending the money I want to make this an improvement over what was stock in this truck. I want to pull with this truck, 6-8k pounds, but still needs to be every day driver. Dont know much about trans so looking for suggestions. Saw a Allison trans on craigslist for 500, saws it got less then 10k miles on rebuild, came out of a short bus. Will it bolt to my transfer case? Saws it will bolt up to my 5.7 350

 

No it wont work. Why would you want an Allison instead of a 4L80E? THAT will bolt in and it is the top of the line heavy duty GM transmission for all workhorse applications.

 

yeah the Allison idea was before I did more research. I talked to a trans guy who suggested rebuilding mine with an HD kit. (My phone wasnt workin well so hard to understand everything he was saying.) Anyway he quoted 950. also included some reprogramer or something that bolts to trans? Gonna head out to his shop to get better details.

 

whatever it is, a 4L80E is the way to go. you can even order direct from your GM dealer or PepBoys but they core charge will hit you because you have a 4L65E and its not the same case.

 

I agree the 4L80E is the way to go....just a side note, the guys in the dealership or store will probably never see the difference, especially if you band it up nice in the crate in the case of a Goodwrench replacement.
Just be sure it is drained well....

 

I have a 4L60E

 

I looked at the 4l80E on ebay, looks different. especially the bell housing. is there an adapter to make it fit. my 5.7?

 

you wont need an adapter because the bell housing bolts up the same, it is the case that is different. These are Chevrolet transmissions so they were designed to bolt up to every Chevy motor. The adapter plates are for non Chevy engines.

 

ok. im rebuilding the 4L60E 4wd trans I have. looking at HD Rebuild Kits. heres one Im looking at is this a good one? any other better choices?

https://www.700r4l60e.com/store/prod...&cat=22&page=1

I want a good one for a steady mix of towing/ off road/ and street. will this effect the gas mileage on this truck?