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stock gear ratio's for 1991 w350?

26K views 9 replies 10 participants last post by  9297oldram 
#1 ·
I have a 1991 W350 picked out to buy, but just want a little more information.

What gear ratio's came in this type of truck? It isn't a dually, just singles on the back.

Also, it is an automatic. Are these automatics 3 speeds or do they have an overdrive?

Lastly, is there a preferred combination in these trucks in terms of reliability? For example transmission types/ gear ratios/ transfer cases?

Sorry for the ignorant questions and thanks in advance for any info. Just want to learn as much as possible about the different drivetrain combos in this year.

Thanks,

Clark
 
#3 ·
a stock automatic 91 will have 3:07s in the rear. It is (if stock) a torqueflite 727 which is non overdrive. the lower gears IE 3:54s and 4:10s were only found in trucks with manual tranmissions.

IMO the best setup would be a standard trans with 3:54s
 
#4 ·
my automatic 1991 w250 has 3.50 gears and overdrive stock. But mine is a 91.5 (intercooled) if yours is the earlier 91 (non-intercooled) it most likely will not have overdrive.
 
#5 ·
89-91 have a non intercooled engine with a 3 speed with 307 gears. the 91.5-93 have a intercooler and overdrive. not sure about gears on the later years you will have to check the tag
 
#7 ·
Non Intercooled ratios:

Auto: 3.07 (727 3spd auto)

Manual: 3.54 or 4.10 (5spd Getrag)

Intercooled ratios:

Auto: 3.54 or 4.10 (518 3spd with overdrive auto)

Manual: 3.54 or 4.10 (5spd Getrag)

I've also read that you could order certain intercooled trucks (it may have been only '93) with 3.07 gears. Not 100% on that.
 
#8 ·
If your options sticker is still there on your hood, inside the engine compartment, it should spell out the gearing your truck was delivered with. Mine had 4:10 gearing which was an option for the getrag.
 
#10 ·
You need to know if it is intercooled or non intercooled. 2wd or 4wd doesn't matter it went by auto or manual trans.

But a 20 year old truck could have had a gear swap sometime in it's lifetime so it's better to pull the cover off and check the teeth count.
 
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