How do i find out what size ALT i have?

[DmccartneyFF2TB]

I need to know the size of my alt to get the correct belt im gonna do a lil more searching on the web also.

[MrSmithsTB]

I don't remember exactly how to find out, but pretty are the bulk of trailvoys came with the 160a alt. That translates to the 91.5" belt. I figured mine out by assuming I had the 150a and getting the 90.5" belt. It didn't want to go on.

[chevycrew]

Run the vin on compnine.

It will give you the rpo codes, and from that, tells the alt size.

[Diacom]

Coulda swore the option was 130a or 150a when I bought a spare belt. Just running off my not so reliable memmory on something I really wasn't paying alot of attention too so don't quote me too much on it.

[MrSmithsTB]

Coulda swore the option was 130a or 150a when I bought a spare belt. Just running off my not so reliable memmory on something I really wasn't paying alot of attention too so don't quote me too much on it.

same here, all I know is that I got the wrong belt and had to go back.

[chevycrew]

same thing happened to me, guessed at it being the 130 since its a LT with limited extra features. But I was wrong, now in the rpo codes I can see mines a 150.

[The Roadie]

No, no, no. The parts stores that even ASK that question are incorrect, and it's been a data base error since 2002. I tried to track down the original source of the error and thought I had it once, but they never updated it.

All trailvoys have 150A alternators, but it's an irrelevant question.

The belt length is ONLY different because there are two different size POWER STEERING pulleys. Larger pulley on the short wheelbase trucks (GMT360), smaller pulley for slightly more PS pump RPM on the long wheelbase platforms (GMT370 [EXT/XL] and GMT305 [XUV]).

Smaller pulley (LWB) gets the shorter belt. Larger pulley (SWB) gets the longer belt.

[DmccartneyFF2TB]

I'm all set I found it kinda dumb way they do it but it's ok thanks guys.

[SomeOffPave]

BUY THEM BOTH
Since Murphy's Law dictates I will be making a repeat trip to the parts store, I buy both and return the wrong one at my convience. Suits me much better than putting the old one back on so I can rush back to the parts store before they close to get the proper one. It is two trips reguardless but much less hassle to buy both initially and KNOW I have the right part when I begin the job.

I admit this does not work if there are more than two choices or if the store has to order a part or buying on line.

[navigator]

just remember some stores charge a restocking fee.
I've done the same thing though, buy two of an item and return the one I don't need.

[DmccartneyFF2TB]

just remember some stores charge a restocking fee.
I've done the same thing though, buy two of an item and return the one I don't need.

Yea luckily enough i work for a diesel shop so we have an account at napa and i can just order and return though work.