1993 W250 diffs

[TRACTJDS0428]

Ive seen several different threads on here and dont see one that says what diffs our trucks came with and what you can do to them. So i was wondering if the diffs were somewhat custom order or did they put the same in most trucks and you had to special order it if you wanted something different?

Next id like to know where i look on the diffs to find out what i have and what gears i have? Is there info on the outside of the diff that will tell me what center section i have? (my truck wont lay down posi's so whats in it? or is it broke?)

And last what effects would it have on my truck if i were to try to run 3.07's (if available) with my A518 OD trans? Sounds like the Non OD trannys needed the 3.07's but are 3.07's too low for an OD? Better fuel mileage? Lug the engine too much?

[dazedandconfused]

Your truck should be 3.55 geared Dana 70 rear and Dana 60 front.

[TRACTJDS0428]

Ok thats what i thought it was. Was the front typically a 30 spline or 35 spline, or did that vary?

[dazedandconfused]

That I don't know I only mess with 2wd trucks.

[GO OVRIT]

It sould be 35 spline inner, 30 spline outer. The rear d70 is a 32 spline. To go to 3.07s you need different housings.(dana 61) I would rather have 3.54 or 4.10 with an od trans.

[dazedandconfused]

It sould be 35 spline inner, 30 spline outer. The rear d70 is a 32 spline. To go to 3.07s you need different housings.(dana 61) I would rather have 3.54 or 4.10 with an od trans.

The 70 could be either 32 or 35 spline but most seem to be 32.

[u2slow]

I was told the D70's are 32-spline if the shafts are retained by bolts (91.5-93) and 35-spline if they are retained by studs, cones, & nuts (89-91). So far I have checked my two '90 diffs with studs, cones, & nuts and they are indeed 35 spline. I ran the BOM on my '93 D70 and its supposed to have 32-spline.

[dunes450r]

I was told the D70's are 32-spline if the shafts are retained by bolts (91.5-93) and 35-spline if they are retained by studs, cones, & nuts (89-91). So far I have checked my two '90 diffs with studs, cones, & nuts and they are indeed 35 spline. I ran the BOM on my '93 D70 and its supposed to have 32-spline.

IIRC generally the 35's have studs and nuts, but not all. there might be a few mismatched ones FYI

[CumminsPower59]

There are some oddballs out there, for example, the D70 I have in my early 91. 3.07 gears, 32 spline shafts, factory Power Loc diff. Most 3.07's are apparently 35 spline units, not mine...