hello guys, i have a 88 s15 jimmy it was 4wd untill i took out the frount diff. i just put on smaller tires becouse im lowering it i uses p205/50r15 on stock alum. 4+4 rims. doing this lowered the truck about 4in. but now the shift points are all roung. now what i need to no is can i just change the ring and pinoin to get it back(or close) to what it was?? if so what do i need to now before ordering a set?? the truck has a modified 2.8l engine with a 700r4 trans. how wouild i no what ring and pinoin to get?? thanks guys please help.

ps i do not want the stock tires on it i like the small er tires just need to get my shift point back were they were.

 

Depends on what you are starting with and what your stock tire size was. Check your RPO code list for the rear end ratio information. Should be GU followed by a number.

 

thanks for replying, the stock tires were 235/75r15. as for the code i looked and did not find any gu codes. i looked on the diff. cover thinking there my be a tag with this info. on it but no luck. i dont no what to do.

can somebody explane what say a 4.10 gear ratio means?? or say 2.73. im trying to figure out would i need to slow the pinon down or speed it up? thanks.

 

4.10:1 means that the pinion rotates 4.10 times for every 1 revolution of the ring which means that for every 4.10 revolutions of the driveshaft, the wheels turn 1 revolution.

For 2.73:1 gears, just substitute 2.73 for 4.10 in the sentance above.

Attached is a snip from the '88 RPO code list. Looks like back then there was either GT or GU utilized for the s-series gear ratios.



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