'88 C3500 454/TH400 2wd single wheel- Dana 60 or 70?

['88C3500]

Hello All,

I've looked around a good bit, and found the rear listed as both. I could pull the cover and measure the ring gear, but I thought that someone here might know. The hsg does not have "60" on the bottom corner web where most 60s do. The top flange surface where the cover seats looks to be 1.25".

Heck, I suppose that it could be a 61 for that matter. It seemed very strange that they went back to a dana after using the 14 bolt for so long.

TIA
Dave

 

['88C3500]

Fwiw, Randy's lists the 70HD for '74-'98 chev and gmc;

http://www.ringpinion.com/b2c/DiffL...&MakeID=3&ModelID=561&Side=Rear&DriveType=RWD

He also lists the 70U and 80 for some GMCs only.
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And here are some application listings for Detroit lockers that indicate that the 70 was used;


Detroit lockers maximize traction by delivering 100% of the engine torque to the wheels. This differential has an exceptional ability to provide traction in various conditions.

For use with 35 spline axles and a factory 2 piece open case.
- Automatic Locking
- Exceptional Traction
- Proven Durability

COMPATIBLE DIFFERENTIALS:
DANA 70HD 35 SPLINE

COMPATIBLE MAKE/MODELS:
CHEVEROLET/CHEVY C30 1 TON (2WD) (1974-1988)
CHEVROLET/CHEVY C3500 (1989-1998)
CHEVROLET/CHEVY EXPRESS VAN 3500 1 TON (1996-2001)
CHEVROLET/CHEVY K3500 1 TON 4WD (1970-1989)
CHEVROLET/CHEVY P30 1 TON VAN (1997-2001)
CHEVROLET/CHEVY P3500 (1997-1999)
DODGE D300 2WD 1 TON (1960-1980)
FORD E-350 1 TON (1980-2008)
FORD E-450 (2000-2010)
FORD F-350 1 TON (1980-1997)
FORD F-350 SUPER DUTY 1 TON (1999-2002)
GMC C35/C3500 1 TON (2WD) (1974-1998)
GMC K35/K3500 1 TON (4WD) (1977-2000)
GMC SAVANA 3500 1 TON (1996-2001)

 

[thz71]

It's a 70

 

['88C3500]

It's a 70

Thanks.

And, I'm Assuming 35 spline. I'll pull cover and an axle when I get a minute.