redneck81toy

i have a 1st generation pickup i have 35's on it now i want to put 38's on it can any one tell me what gears i need

SloPoke

5:29's.

934rnr

I would say more like 5.71's for 38's if you have a 4 cylinder.
I think they are only available for the 4cyl diffs though.

5.29's would be a good ratio for 35's.

Anyways if you are looking for a good price on a set of quailty gears call Randy's Ring and Pinion. They quoted me the other day on a set of front and rear Yukon 5.29's with master install kit w/timken bearings for $389.
here's thier site: http://www.randysringandpinion.com

I am thinking of regearing just to save on gas I think it would be worth it in the long term.

superjoe83

if you go with the 5.71's, don't wheel it too hard those are notorious for breaking because the pinion doesn't have enough teeth to distribute the load, my friend has a 83 with 36" swampers and 5.29's do fine with those tires, so 38's wouldn't be too much worse

934rnr

http://zukaz.tripod.com/571.htm
Zuk is selling a set. I too have heard that rumour. I haven't seen a failed set to know if that's it or not. There are too many holes in the subject on those gears. Like what was the backlash set at how was the drive and coast pattern on the intial setup. The brand of gears also matters as well. I am curious were the 5.71's that failed US Gear or Yukon's? Likely they were Genuine Gear brand which most people know are junk.
I know if gears aren't setup correctly they will fail over time.

Flygtenstein

5.29 pinions have the same number of teeth as 5.71's

Is it a trail only rig?

Do you have dual cases?

superjoe83

ok, i apologize for the incorrect info about the pinion teeth count i had been misinformed, so, with the pinion having the same number of teeth, then why do i hear that 5.71's are "weaker" than 5.29's, does the extra teeth on the ring of 5.71's make the pinion teeth different shape or angle, i would like to know this because I'm planning on buying a 79-85 truck and running 35-36's and would like to get the lowest axle gears possible because its going to be a trail truck

SloPoke

It not the pinion that fails but rather the ring geart itself. With that many teeth machined in, there's not enough mass left there to hold the teeth solid when applied with massive amount of torque. When you get up that high, the machining process removes to much mass in order to fit that many teeth on the ring.

Not sure if that was an easily followable answer for ya but it's the best I gots.

kyle_22r

there's only a couple more teeth on the 5.71 ring gear imho. i'd like to see how zuk's setup goes, it could dispell a lot of the hearsay about those gears.

Flygtenstein

People wheeling "hard" seem to have made the reputation for 5.71's failing a lot of the time. I have not seen or heard of a 5.71 failure and I have been web wheeling for quite some time.

Most people say 5.29's are weak, then people ask why and the retort is because of the small pinion. I just meant to say that they are the same tooth count and therefore I would assume the same size.

People also trash 5.29's but they are sort of the advisable limit that most adhere to.

I would not install a 5.71 gear set into IFS since the ring gear and pinion are smaller.

If this is a trail only truck with dual cases, I would see what his current ratio is and find how satisfying it is.

If it does not have dual cases and is not a trail truck, I fail to see how 38's with a 4 cylinder are even worth considering.

toy283

I run 4.11's with 38's I agree with Flygtenstein though. Run the 5.29's and either suffer the power loss (your gonna have one anyway) or don't go to 38's.

kyle_22r

there's a guy i went to high school with who has an '83 with 5.71s and 38.5s. he jumps the truck on a regular occasion(ouch!) and hasn't broken a ring gear, besides the ones he put in himself(just slapped it in there, didn't even bother to check pinion depth or anything...blew up in the first 20 feet of use)

not to mention he has a 283 that's pushing around 300hp. i'd suppose the automagic th350 soaks up some of that, but something must have been done right

Flygtenstein

Jumping is abusive to the suspension, getting stuck in rocks with low gearing and high traction is abusive to drivetrain components.

I have seen ring gear failures and pinion gear failures. Both are hideous.

redneck81toy

thanks for all the help i was also wondering if i need to change axel housings

kyle_22r

but what about jumping with your foot on the throttle? i'd imagine that would cause some pretty nasty shock loading when you hit the ground...

Mallrat

ok well here's some food for thought for you. I have an 85 Runner on 38.5 TSL SXs and Im running 5.29s and drove the truck from Va Beach to Brunswick, ME on them and didnt have any serious problems. Hardest part was on the NJ Turnpike cause I couldnt get it much over 80mph. 5th gear is no longer a gear unless you are over 65mph. 5.29s are enough if youre just driving around town. Me personally, im going to drop down to 37 MT/r's

Good luck, and no you dont need to change your housing, but you might want to go for a wider housing while youre at it if it doesnt already have it!

Josh

934rnr

Here's a pretty neat comparison of 5.29 gears to 5.71's Zuk did up: http://zukaz.tripod.com/529.htm

SloPoke

Looks to me he pointing out that the 5:71's are thicker. That's the case with the ring itself but look how shallow those teeth are compared to the 5:29's. Hence, much easier breaking with less surface area to spread the torque load = snap!

They are not brittle by no means but if your really crawlin' and get bound up, the 5:71 will break long before the 5:29's.

Comapre the tooth depth of the 4:56's/4:30's/4:11 and you won't see much difference. Just more of less of em. On the 5:71, they had to go shallower to fit that many teeth around the same size ring.

Anyways....thanks for pointing that comparison out.