rear diff lock suggestions?

7183 Views 17 Replies 7 Participants Last post by MichaelSt, Sep 20, 2010

MichaelSt

Discussion Starter · Sep 15, 2010

so i went with a 38 weber and i will be installing that today :clap: and i recently found out that because my truck had a 4speed manual, it came with an 8inch ring gear:chug: so ive decided i will go with 4.88. but since i will be swapping the whole third member out... i was wondering if there is anything else i should be doing? i will do the axle bearings diff seal and brakes while i am at it.. anything else? also i might want to add a diff locker.. how should i go about this? thanks guys!

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fourwd1

· #2 · Sep 16, 2010

First off, 2wd or 4wd (4wd's have an 8" rear period, 4 spd has nothing to do with it)
what engine?
transmission?
what's your current ratio?
tire size?
why did you decide on 4.88?
as for installing a locker, it requires dis-assembly of the diff, and some lockers require more work than others.

MichaelSt

Discussion Starter · #3 · Sep 16, 2010

Oops sorry. Its a 1989 2wd origionally with a 4speed. About a 4inch lift and 31 inch tires, current gear is 3.07 I was told the the 2wd with speed trannys came with an 8inch. I checked and sure enough! Well I think that going 4.88 will be a little steep but I might be going 33 inch tires soon. My friend has a 98 his gear is 4.88 with 33s and its seems perfect.. of course I'm on here going over ideas just in case haha

hoe_nah

· #4 · Sep 16, 2010

33s on a 2wd? wow that should be interesting ive never seen that hahaha...no rubbing issues?

fourwd1

· #5 · Sep 16, 2010

Fitment aside

I think 4.88 may be way too low.
While 4.88 is the ideal ratio for 33's on a 4WD truck, the stock ratio is typically 4.10.

In 4th gear -
With 3.07 gears and 31" tires you should be around 2000 rpms at 60 mph
With 4.88 gears and 31" tires you should be around 3200 rpms at 60 mph - too high
With 4.88 gears and 33" tires you should be around 3000 rpms at 60 mph - too high
With 4.10 gears and 31" tires you should be around 2700 rpms at 60 mph
With 4.10 gears and 33" tires you should be around 2500 rpms at 60 mph

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MichaelSt

Discussion Starter · #6 · Sep 16, 2010

yea hes only got a little rub in the front. you do have an excellent point though.. maybe go with the 4.10 or 4.37?

IronNam

· #7 · Sep 16, 2010

check the driver's doorside jamb, if he has G series, then he has 8" diff.

MichaelSt

Discussion Starter · #8 · Sep 16, 2010

already did, g662. 8 inch, 3.07 gear. 2 pinion open.. whats thedifference between open and closed by the way?

fourwd1

· #9 · Sep 16, 2010

Open as opposed "locked". An open diff allows the wheels to rotate at different speeds when you make a turn. Most stock diffs are open.
Look here http://auto.howstuffworks.com/differential2.htm

IronNam

· #10 · Sep 16, 2010

go do a burnout. you'll figure it out

MichaelSt

Discussion Starter · #11 · Sep 17, 2010

kinda figured.. just dont want to end up getting the wrong diff. thanks FOURWD1

exist

· #12 · Sep 17, 2010

I'd personally go find a 4.10 something from a 4x4, v6 or 4 cyl whichever you can find first - they're dirt cheap .. Then get a spool.. Driving something locked 100% of the time isn't as bad as people say.. I find it pretty fun personally.

HEAVY_GD

· #13 · Sep 18, 2010

exist said:
Driving something locked 100% of the time isn't as bad as people say.. I find it pretty fun personally.

:thumbsup: agreed.

exist

· #14 · Sep 18, 2010

Somethings up with my clutch that keeps it kinda partially engaged, or not fully disengaged .. whatever .. so even when I push the clutch it my locket doesn't unlock (lockright) unless I pop it out of gear..

You get used to the clunks (which you wont get with a spool) and you get used to the rocking and violent bucking when you don't turn into a parking spot ... right ... I'm sure some of you other locked guys know exactly what I'm talking about..

My personal favorite for a locker and street driving is new asphalt .. The squeeling around the corners going like 10 kph and revving low and everyone staring is dope.

HEAVY_GD

· #15 · Sep 18, 2010

Do you have the silencer and stock springs in it? I've seen mods done to detroits that keep them partially locked.

Vicoor

· #16 · Sep 19, 2010

Driving a spool on the street can be pretty touchy when the roads are slick (even if some people like to). So unless you plan to wheel that thing where you will be lifting one or the other rear wheel off the ground, a locker or spool would not be necessary.

A limited slip diff would probably be more approriated.

Detroit true tracs work real good, but are a bit pricey. some people find limited slip diffs from 1 ton toyota pickups in the junkyard.

As far as gears, I had an 80 celica with a 4 speed (no idea what the ratios where) but it turned 3000rpm/60mph, 3500/70 4000/80, could run 80 all day with 250k on the clock.
Currently I'm running 4.10 gears in my 2wd truck with 26" tires. With a w58 trans that gets me about 2700/60 3200/70.
Now you would lose some gas mileage, but if your engine is sound it wouldn't hurt to run 4.88s, and the plus side, it would boost your rear wheel torque off the line.

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MichaelSt

Discussion Starter · #17 · Sep 20, 2010

haha a little clueless now =/ another friend has an 03/04 yota and has the diff lock.. im thinking about something like that, do they come cheap or not worth it?

MichaelSt

Discussion Starter · #18 · Sep 20, 2010

oops sorry didnt see that last post. yea VICOOR, i do long trips every now and then, and i ran the math on it 4.56 would extremely agressive like im looking for and i think i can deal with long traveling with that set up. kinda harsh.. for economy 3.73 would be the best pick so i guess i just need to choose somewhere in the middle.. Torque VS mpg/longer engine life..

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