[gdaymatee]

I only recently bought my first sierra, its an 88 model WT hardtop. The rear diff was stuffed in it so I bought another diff to replace it. I have changed it and have seen that maybe the 88 model has different ratios to later models (which I think the new diff is from).

So if anyone can clear up for me if this is the case or not then that would be great!

Also if they are different, will it be a big issue if I engage 4WD and the front and rear diffs are different ratios....?

I'm guessing things will go bang...

[Fatzook]

If its the Early WT with plastic flaes the ratio will be same as later WT with 3.7's.

And having different ratios will cause damage eventually.

[shep]

count the teeth on the one you pulled out just to be sure.

[gdaymatee]

Ok thanks. Yeh its the early WT with plastic flares, so hopfully its the same then! great!

If I count the teeth on the old one im guessing its the pinion teeth im counting? How many am I looking for to have a 3.7 ratio?

Thanks for the quick replies!!

[ellis]

fatzook did u get my pm i sent you?

[boostedbrick]

http://www.csgnetwork.com/rnggrpinioncalc.html

Ratio calculater to make it easy

[Fatzook]

ellis wrote:

fatzook did u get my pm i sent you?

Yep. Sorry I skipped over it. Got 36 PM's that day

[shep]

crown wheel has 41 teeth for a 3.7 or 43 for a 3.9 both ratios have the same
tooth count on the pinion gear.

[BlueSuzy]

I alway thought 88' WTs plastic flares were 3.9 with 4 pin carriers front and back.

And the bloke that got my 88'WT LWB whole original diffs is selling the 3.9 gears..

88WT's are NT flanges. Smaller M8 bolts/ Normal WT's are M10

Count the teeth on the crown fatzook.
http://www.auszookers.com/index.php?nam ... ic&t=18136

Zoom in on the picture in its own page. I counted 43 twice.

Mine was as original as can be. Came with a stock AM radio, turn dials and 1 speaker stereo. 140,xxxkms ish (but was 139,xxx on beach by the looks of things with the uber rust)

Count the teeth gdaymatee. That will confirm your answer, it will also confirm who is right for next time the ratios questions pop up again.

[appsie]

timmy my new soft top is wt 88 with plastic flares and also some old WTs i bought off dan(tuff truck vit) were also.They have 4 pin front but are 3.7 with the small flange for the tailshafts.they run NT shafts.

[BlueSuzy]

Maybe its just the LWB's then? Bloody crossover years..

[Fatzook]

I don't have mine anymore, but it was definately 3.7's.

[shep]

20 year old car so it could have nearly anything in it. i only assume that something is stock
if i bought it new.