33's with 2.73 gears - questions

[Polaris]

33\'s with 2.73 gears - questions

So my truck has the factory axles with 2.73 gearing according to the RPO codes. I have a 700R4 tranny, rebuilt last year and still under warranty. I'm running 33" Pro Comp M/T's and going offroad in some tough stuff this weekend. Lots of mud, some rocks, stuff like that. The thing I notice so far with highway driving is that if I try to run in OD it just slows down. It downshifts an awful lot so I've just been running it in drive for the most part. Then the RPM's seem kinda high. I hope to put in 4.10's next year but money limits me right now. I am wondering is running in Drive the best idea? Also what can I do to prolong the life of my wimpy axles? What should I avoid?

Thanks very much! Leaving tomorrow for that big weekend. My rig's first time on the Pipeline. Fun!

 

[nofeartruckin00]

Re: 33\'s with 2.73 gears - questions

How high do the RPM's get in 3rd gear? I wont shift into 4th until 70mph, around 3000 RPM's. But that with 4:10's. Sorry, that probably wasnt much help /forums/images/icons/smirk.gif

 

[8_YOUR_H2]

Re: 33\'s with 2.73 gears - questions

You can keep it in drive all day long. I had 36" swampers and 3.42's, OD was useless unless I was going down hill. WIth gears that high and larger tires its not going to put as much strain on the axles as say a 4.56 would so you could expect some longevity with the setup you have. I bet gas mileage is good!

Any way just keep it in drive unless you hit, oh, 120 or so then kick in the OD /forums/images/icons/grin.gif

 

[Polaris]

Re: 33\'s with 2.73 gears - questions

Need a tachometer. Goes about like "hmmmmmmmm" so can ya help? LOL. Doesn't scream or anything.

See ya this weekend! I can't wait to be OUTTA HERE!

 

[Polaris]

Re: 33\'s with 2.73 gears - questions

That's the truth! LOL.
________________________

Any way just keep it in drive unless you hit, oh, 120 or so then kick in the OD

 

[nofeartruckin00]

Re: 33\'s with 2.73 gears - questions

Lets see, if its goes hmmmmmmmmmmm, your doing about 2500 RPM, so you are fine. If its starts going Hmmmmmmmmm, you are getting alittle over 3000 RPM. But, should it ever go HMMMMMMMMMMMMMM, you better get out of the truck, because there are some bees in the back seat /forums/images/icons/grin.gif

See ya on sunday, hope i dont get too muddy....... wait, yes i do!

 

[69K5]

Re: 33\'s with 2.73 gears - questions

what arer rpo codes and where do you read tham and find out what they mean? my axels are unmarked and the tabs are gone

thanks

nathan

 

[Polaris]

Re: 33\'s with 2.73 gears - questions

On my '90 there is a sticker in the glove box full of 3-digit codes. This will only be accurate if no one has changed the axles or gears. I'm confident they haven't on mine because of all of my lovely experiences working on the thing. No one did squat with it! So I compared the glove box codes with the ones at this page . Hope that helps and that your news is better than my 2.73's! /forums/images/icons/crazy.gif

 

[69K5]

Re: 33\'s with 2.73 gears - questions

well mines a 69 and has the options written out but doesnt say squat about the gears. i know the axel says GM 51 ans has lots of other numbers but i think they are just part #'s. thanks anyway

nathan

 

[Thunder]

Re: 33\'s with 2.73 gears - questions

I would definatly keep it out of overdrive with those small gears and 33" tires. I ran the numbers for the 33" tires and 2.73 gears and at 65 mph you are only turning around 1200 rpm. Thats way too low for a 700 at freeway speeds. It may damage it. Thats why it shifts in and out of overdrive so much. Even in drive you will only be turning around 1800 or so at 65 so that should be ok till you get diferent gears. But I would get the higher gears in ASAP.
I wouldn't worry about your axles and 33" tires they should hold up just fine. I run 33s with a locker and a 10 bolt. I beat it. tow with it, and drive fast. and it holds up just fine.

 

[bablazer73]

Re: 33\'s with 2.73 gears - questions

my wifes 87 had 3.42's with 33's. she couldn't use overdrive unless on highway goin 60+ mph. so i would keep it in drive.

 

[BLUESMAN]

Re: 33\'s with 2.73 gears - questions

I once had 3.08's with 33's and a TH350 trans.The truck was a dog,could'nt shift into 3rd until 60mph.I can't imagine 2.73's and a TH700.Definitely keep it out of overdrive,might want to manually shift that trans until you get some decent gears.Mike

 

[4x4Freak]

Re: 33\'s with 2.73 gears - questions

My truck with 2.76s, th350 and 33s runs about 2300 rpms at about 70 mph. That is already like overdrive, my 00 v6 silverado runs about 2100 rpms at 70. It finally gets into its power range at about 80 or 90. My gas mileage SUCKS because the engine is having to work too hard to keep the truck going. Cant wait to do the 3/4 ton conversion.