1991 Suburban Gearin

[aglinks]

Hey all,

I have a 1991 Suburban V1500 with a 350 and TH700r4. I installed a 4" Superlift and 35" Cooper MTPs and it looks amazing. Factory gearing is 3.73 but now its impossible to get up hills so I think I need to re-gear. I am thinking of going with 4.56 and a rear locker so I can tow my jeep, any thoughts or advice?

 

[Lu Blunt]

http://www.grimmjeeper.com/gears.html

Good place to calculate rpms n mphs

 

[74 Shortbed]

Yep, good place..

http://www.grimmjeeper.com/gears.html

 

[aglinks]

A lot of the kits I am seeing online for the GM 10 Bolt say they are for 1980-1987 GM Half Ton trucks. Did the axels change from 1987 to 1991?

 

[marks86]

Find a 3/4 ton burban with a 14bolt FF rear. Some had 4.56 gears, or get a cucv rear-end with 4.56 and factory Detroit and have the perches rewelded.

10bolts with big tires and tall gears are so unless on a big heavy truck.

 

[VAL]

I have the exact same setup 350, 700r4, 3.73 gears from a 90 burb axles, and 35s. I ditched the original axles with 3.08s. After the axle swap I could swear It felt as if I got another 100 horses under the hood, and it climbs hills like nothing, and cruses effortlessly at 75-80 on the freeway. But then again my truck isn't as heavy as your burb.

 

[aglinks]

Overall my setup would be fine for probably 90% of the country. I live in Flagstaff AZ and drive back and forth to Phoenix which is a 6000 ft elevation change. The last 3000 ft of elevation gain happens over like 15 miles which is the real killer part. I dont want to put different axels under the truck because that is far more work and want to keep the truck as original as I can. Had to go with bigger tires and a lift due to my driveway being so steep and the suburban being soooooo long. My receiver hitch dragged the pavement on factory springs and 33's when I tried to drive up my driveway haha.

 

[aglinks]

Is there any issue with installing limited slip front and rear? This truck has open diffs.

 

[glockholiday]

I like this chart http://4lo.com/calc/geartable.php

 

[aglinks]

Looking at the charts, I think 4.56 or 4.88 is the way to go for me. Does anyone have a suburban with 35's and either of those ratios?

 

[bucket]

You are on the right track. IMHO, 4.56's work well even without overdrive.

 

[aglinks]

I just got my gearing done. I now have 4.56 gears and a Yukon Dura-Grip in the rear. I havent had the chance to take it offroad yet but it does great at driving up hills now haha