92 wrangler 4.0 real slow

kelly91 · #1 (**permalink**) 10-08-2009, 01:35 AM

I convinced my wife I needed a commuter car. I have always wanted a jeep ibought a 91 tj 4.2 it does not go over 70 on freeway and that's downhill. I have taken it to a few mechanics (so called) and can't seem to get any results. The last guy replaced# 4 injector and new muffler, first guy new fuel pump and computer (I think he was a crook). I have 32 inch tires and a two inch lift. I just can't seem to get in 5 gear on freeway. Help please willing to put some money into it just don't know where to spend it. I know a jeep is not a commuter car just needed a good excuse but was hoiping to at least get something to use on freeway.

SteelHeadz · #2 (**permalink**) 10-08-2009, 07:30 AM

Welcome to Jeepz. 91?, that would be a YJ .. Check the gears on your axles and see what gear ratio you have in there. It's more likely that it still has the stock gears that's keeping you from using the 5th gear.

Bounty__Hunter · #3 (**permalink**) 10-08-2009, 02:28 PM

'91 YJ is a 4.0L engine and makes pretty good power. Sounds like your problem is the stock 3.07 axle gears pushing oversized tires. Only fix is to regear the axles to 4.11 or install smaller tires.

Dogbytz · #4 (**permalink**) 10-08-2009, 04:17 PM

My YJ has a 5th gear??? LOL

kelly91 · #5 (**permalink**) 10-08-2009, 05:45 PM

Thanks for the quick response. Will definately check the gears out. I am in the riverside california area anybody know any good jeep mechanics

Bounty__Hunter · #6 (**permalink**) 10-08-2009, 10:37 PM

Check the tag bolted to either diff cover and post the numbers here.

ATK1 · #7 (**permalink**) 10-09-2009, 11:06 AM

Quote:

Originally Posted by kelly91

Thanks for the quick response. Will definately check the gears out. I am in the riverside california area anybody know any good jeep mechanics

Might want to try T&J Performance Center in Orange (714-633-0991)...short drive from you (so much for using 5th gear! LOL) , but Jake will definitely take care of you (tell him James sent ya)

kelly91 · #8 (**permalink**) 10-13-2009, 04:35 PM

I was looking under my jeep and found a metal plate screwed to my transfrer case with the numbers 231j, 5300, 8212, 13, 921, 272. Is my gear ratio located in those numbers?

SteelHeadz · #9 (**permalink**) 10-14-2009, 07:42 AM

Quote:

Originally Posted by kelly91

I was looking under my jeep and found a metal plate screwed to my transfrer case with the numbers 231j, 5300, 8212, 13, 921, 272. Is my gear ratio located in those numbers?

Yes and no. That's the gear ratio on the T.case but not the axles. That t.case is a 231J with a 2.72 gear ratio. The axle tag should be attached on one of the bolts on the differential cover in the front axle or the rear. You might have to clean it up a little if the covers are all gummed up with mud or grease to see the tag.

sledd · #10 (**permalink**) 10-17-2009, 12:06 AM

My 91 YJ (4.0) was losing power big time and it turned out to be a plugged catylitic.I changed it and the muffler and huge difference.Hope this helps...