ring and pinion gearing question

[Destruct O]

My supervisor was telling me the other day that he just had a re-gear done to his truck. His trucks know has a 5.29 rear and a 5.38 in the front. His assistant over heard us talking and he started screaming, you are going to rip your axle right out of your truck when you put it in four wheel drive! The ring and pinion ratios have to be the same and they started arguing. The boss was saying "it is not that much of a ratio difference it will help pull you through the muck, I could see if the truck was running 4.88 in the rear and a 5.38 in the front then I would be worried".

Can some of you Gear tech Gurus please help me with these questions.

Can damage occur to your rig by having mix matched R&P gear ratios? If so what kind of damage would be done?

If you can mix and match ratios is there a way to find out which ratios will work together and which ones won't?

Thank you for your time.

[skid]

Try driving a locked up 4wd on the pavement with the same gears.  As soon as you start to turn,  it binds up.   In the dirt, it slips.    Off road, you'll probably never notice the difference between the 5.38's and 5.29's.   It's been done countless times.  I highly doubt any trouble would ever become of it.  If you're really worried, drop the tire pressure in the rear a little more.

On another note, it would be pushing though the muck.  The rear tire would be spinning faster with 5.29's.  Less bind would occur if the front had 5.29's and the rear had 5.38's.   This way, moving forward in corners the tires speeds would even out a little becuase the rear travel less distance.

[Shamb]

ErikB on the pirate board has been running 5.29/5.38 combo for over 4 years now without any problems.

[DTB]

ErikB on the pirate board has been running 5.29/5.38 combo for over 4 years now without any problems.

I can see that this would work fine off-road......but wouldnt the gearing difference put a lot of unnecessary strain on the drivetrain, i.e. one set of tires pulling or dragging a little bit?

[toynorcal]

I can see that this would work fine off-road......but wouldnt the gearing difference put a lot of unnecessary strain on the drivetrain, i.e. one set of tires pulling or dragging a little bit?

The gear ratio of the front axle only matters if you are in 4WD and 99.9% of that is off road or icy...so no, there would be no strain to the drive train in 2WD

[79coyotefrg]

ive seen mud trucks  use this set up alot,  but  i  wouldnt  want to do it on a hard slab 

[prang11]

best to run the same gear set front and rear.  I could see how in some cases it would matter less than others but on the rocks it would add alot of unessecary strain.

[Hottrod81]

Some people will run this setup because they run different tire pressures in the front and rear which has an effect on the tire height.

[S-10 Stewy]

I read in an article in Petersen's sometime ago that a 7% difference in ratio is considered "tolerable".  I personally like the "same" F&R.  Hundreds of thousand of full size 4wd GM trucks came out of the factory with 4:10 in the front and 4:09 in the rear.  The biggest complaint you always hear about those rigs is "I can't get the thing out of 4wheel", never "it drove bad".

[IronClad]

yep  just fine.. lots of trucks came factory with diff ratios.. nothing new and it wont do anything bad.. the ratio is to close

[Destruct O]

Hundreds of thousand of full size 4wd GM trucks came out of the factory with 4:10 in the front and 4:09 in the rear.  The biggest complaint you always hear about those rigs is "I can't get the thing out of 4wheel", never "it drove bad".
[/quote]

My Uncle complains that his 69 Chevy won't come out of 4wheel drive, and also complains that as soon as he turns the hubs it is already in 4wheel drive before he engages the t-case.

Will a IFS or even a SASed Toy suffer the same fate as the fullsize Chevy's with mismatched gearing?

I also hear Toyota's have a bad reputation for having a small, weak Ring and Pinion, the articles I read say another Toyota down on the trail with a broken ring and pinion the never say if these gears are stock or aftermarket, can someone help with this.

[Shamb]

the HOUSING is thin on a stock Toyota axle but ring and pinions can take some punishment, if you have a lead foot and like to bash it then there's always cryo'd gears.....

[S-10 Stewy]

Hundreds of thousand of full size 4wd GM trucks came out of the factory with 4:10 in the front and 4:09 in the rear.  The biggest complaint you always hear about those rigs is "I can't get the thing out of 4wheel", never "it drove bad".


My Uncle complains that his 69 Chevy won't come out of 4wheel drive, and also complains that as soon as he turns the hubs it is already in 4wheel drive before he engages the t-case.

Will a IFS or even a SASed Toy suffer the same fate as the fullsize Chevy's with mismatched gearing?

I also hear Toyota's have a bad reputation for having a small, weak Ring and Pinion, the articles I read say another Toyota down on the trail with a broken ring and pinion the never say if these gears are stock or aftermarket, can someone help with this.

I don't know if I would say they have a "bad" reputation .... Shamb is right, those lil suckers can take some abuse!  Could it be the "weak link" in the rear end???  Yeah, I guess.  But that does not mean there weak.  The Japs did it right when the engineered those axles!  They WILL take a beating if set up right.

[blackdiamond]

I really doubt it was cause any more stress in the drivetrain than my truck turning on the rocks in Moab with lockers front and rear and the 4.70 transfer case gears.  It seems to have survived just fine.

[Rockcrawlintoy]

I have that combo in my truck. it doesnt really bind more then it did stock.

Drew