Direct drive vs. gear reduction starter

[Hoesgottaeat2]

Hi all.
Working on my ‘96 Burb, 5.7L. Replaced many starters on these GMT400s in the last 15-20 years. First time I ran into this.

Removed the starter and ordered a new one from RockAuto. Didn’t pay too much attention to the fact that I ordered a “direct-drive” type. The new starter showed up today and the motor on it is considerably larger, however at first comparison it looks like it will still fit. Won’t know until the weekend when I attempt to install it.

Have any of you used the “direct-drive” type in lieu of the “gear-reduction” type that I typically have seen in these trucks? If so, what’s the advantage of one over the other? Any negative experience going this route?

Here’s the physical comparison. It’s kind of hard to miss lol…

 

[east302]

My 98 came with the larger type. Other than the weight, the only difference I remember is very slightly longer cranking time. It wouldn’t be enough to make me bother with a return, though the gear reduction uses less power. It does need the heat shield - looks like you might already have that if it will fit.

Some have seen differences in the starter bolts, the gear reduction requiring a slightly shorter length so that the knurled pattern stays about halfway into the starter body . I didn’t have that issue with my 98. Stock direct drive bolts (images below) worked fine with the gear reduction so the reverse may apply to you.

 

[Hoesgottaeat2]

My 98 came with the larger type. Other than the weight, the only difference I remember is very slightly longer cranking time. It wouldn’t be enough to make me bother with a return, though the gear reduction uses less power. It does need the heat shield - looks like you might already have that if it will fit.

Some have seen differences in the starter bolts, the gear reduction requiring a slightly shorter length so that the knurled pattern stays about halfway into the starter body . I didn’t have that issue with my 98. Stock direct drive bolts (images below) worked fine with the gear reduction so the reverse may apply to you.

View attachment 387018
View attachment 387019

Thanks! I'll go for it then. I compared depth of the bolt holes on both last night and they were essentially identical when placed side by side. With the info you just provided I will give it a go and post back afterwards how it went.

 

[Hoesgottaeat2]

Installed the starter today and it fit perfectly. Heat shield looked way too small so I left that off. But it started right up. First thing I noticed different was the cranking sound. Very old school sounding. My wife’s ‘70 Nova starter sounds near identical. If I would have known I was getting an old school sounding starter, I would have bought it intentionally instead of by mistake like I did lol! Thanks for the help folks!

 

[drakon543]

direct drive is the older version so yes it basically would sound identical. direct drive generally also rotates slower. the
direct drive was also oem version on alot of gm truck until the later end of this model. the gear reduction starter was put on in place of it due to alot of direct drive startels not even making it a year except for the original.

 

[Eman85]

Bolts are definitely different, but if it works go for it. Small blocks use 2 different bolt patterns for mounting the starter depending on flywheel size. As long as the bolt pattern is the same it will work fine.