I have not had my suburban for very long, so I really don't know much about them. As such, I was wondering...what type of axles do they have, in particular a 1989 v1500 350 4x4 with 373 gears? And, the previous owner had purchased 31 inch tires for a more "aggressive" look, which I love. However, at highway speeds of 55, I have to shift into overdrive. And if I go below 55 in overdrive, the engine really seems to lag. So, would putting in, say, 342 gears fix that? Thanks for any help.
CK5
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New gears
- Thread starter OEMTDM
- Start date
SUBFAN
1/2 ton status
Axles are front and rear 10 bolts, (if they are stock)
Changing to 3.42 gears will not help at all. Open the diff cover to verify they are actually 3.73's.
Lack of power, and to steep of an overdrive gear are causing your problems. With the hills surrounding you, deeper gears like 4.10-4.56 will be the most helpful.
This a perfect candidate for a 3/4 ton swap to find the right gear set....
Changing to 3.42 gears will not help at all. Open the diff cover to verify they are actually 3.73's.
Lack of power, and to steep of an overdrive gear are causing your problems. With the hills surrounding you, deeper gears like 4.10-4.56 will be the most helpful.
This a perfect candidate for a 3/4 ton swap to find the right gear set....
txfiremank5
1/2 ton status
Yeah, like subfan said, you need gears that have a "higher" number.
I'm just wondering why your sub is lagging on the highway with 31" tires and 3.73's... especially with TBI. Does it have a 305 or something?
My 89 K5 with 32's and 3.42's runs like a scalded ass ape .. on the street or highway. Everything is stock, including the tbi 350.
Sounds like something is going on .. either the gears are not 3.73 or possibly something else needs to be addressed. I'd give it a good going over.. it may be tune up time. My 84 K5 had a cat converter that was getting clogged and it really hampered performance. Anyway, just throwing out some ideas... it really should be running just fine w/ 3.73's and 31"s.
I'm just wondering why your sub is lagging on the highway with 31" tires and 3.73's... especially with TBI. Does it have a 305 or something?
My 89 K5 with 32's and 3.42's runs like a scalded ass ape .. on the street or highway. Everything is stock, including the tbi 350.
Sounds like something is going on .. either the gears are not 3.73 or possibly something else needs to be addressed. I'd give it a good going over.. it may be tune up time. My 84 K5 had a cat converter that was getting clogged and it really hampered performance. Anyway, just throwing out some ideas... it really should be running just fine w/ 3.73's and 31"s.
Scalded ass ape....Booya. Thanks for the help, I believe it is time for a look-see to determine what the hell is wrong. Maybe I should just fork over the cash and throw in a 383 stroker. Nah, I'm po'. Oh, another question...I think that 35's would look great on my sub. Besides a lift kit, would I definetly need different gears? Keep in mind, I'm a real newb to this, hehe.
txfiremank5
1/2 ton status
Oh I bet 35's would look sweet. If you go that route, go with at least 4.10's minimum. Some here, are more extreme .. and will say 4.88 no less.. 
However, it depends on what you are doing etc. If you expect to get good gas mielage with it and drive it on the road etc, I would not go too low (hgher number). You would probably be happy with 4.10's, and could even go up to 4.33's just to have that extra seat of the pants kick... I doub I myself would go any higher than that with 35's. Maybe 4.56's ... depending.
Go to www.4lo.com and look at their gear chart. It will tell you what type of RPM you are running now, and what type you will be running with different gears and tires etc.. and you be the judge of what you think will best fit your needs.
However, it depends on what you are doing etc. If you expect to get good gas mielage with it and drive it on the road etc, I would not go too low (hgher number). You would probably be happy with 4.10's, and could even go up to 4.33's just to have that extra seat of the pants kick... I doub I myself would go any higher than that with 35's. Maybe 4.56's ... depending. Go to www.4lo.com and look at their gear chart. It will tell you what type of RPM you are running now, and what type you will be running with different gears and tires etc.. and you be the judge of what you think will best fit your needs.
txfiremank5
1/2 ton status
Sorry, it's under the "ideal ratio chart" .. and looking at it.. 4.56's ,might be pretty nice. Even though I typed 35" tire, I was thinking 33" .. 
so, yeah, a 4.56 could be a pretty number for you. But, like I said, it depends on what you are looking for.
so, yeah, a 4.56 could be a pretty number for you. But, like I said, it depends on what you are looking for.Well, I'm really looking for take-off and cruising power, as I drive about 40 miles to school everyday. Also, driving that far..mileage is a concern. The only time I have turned on the 4x4 is when it has snowed, in which case all the new trucks with ninny tires were stuck, but I was plowing along rather nicely. But, like i said, thats as far as I've gone with the 4x4; mostly it's a road machine. Your help is mucho appreciated, I don't feel nearly as lost now haha.
SUBFAN
1/2 ton status
Looking to go 35's, then start looking for 4.56's or better....I never even used OD with my 3.42 35" set up....
shane74
1/2 ton status
If you want to run 35's w/out rubbing, you'll need close to 6" of lift. Also, with your tranny, you'll need 4.56 gears minimum if you want to run 35" tires.
