Need advice on gearing.

4:88 , 32" tires ,3000 RPM's = 55MPH according to GPS in my JEEP.

Can't wait to get a overdrive someday.

 

Yeah, that's pretty close - better than +/- 6%. The calculator says it should be 58.5 mph. Though labelled as 32s, your tires may not really be as tall as 32" ... I expect you could get a better estimate of the effective tire diameter by measuring the circumference and dividing by pi (3.1415926).

 

3000 rpm at 55-60 with my 31s!!! Thats not good for what I want it to do. I am not going rock crawling,,, Heck we don't even have any rocks down here. I am going in sand and some mud. Regearing 2 axils is out for now. And regearing 1 and a overdrive is going to have to wait. It looking like 3.54 for now and saving the r/p for the d44 for later? Guess I will still have to think about it. Does any one know what size the spindal nut is?

 

Hate to burst your bubble, but to use the 3.54 front, you NEED 3.54 in the rear (need new carrier). Same with the 4.88 gears. The transfer WILL NOT be happy with dissimilar gearing. Save the $$$ and do this right the first time.

 

Oh I know I need a new carrier either way I go. Maybe I did not put it right but,, I was talking about just going with the 3.54 for now in both axils.I need to get it on the road and wheel it for a while to see what I will be happy with. I do not want to get caught up in putting a bunch of mods in I really do not need right now. I will put it on the road with the new d30 p/s and disc brake conversion. And the 3.54 for now. I will keep the d44 r/p and old carrier. just in case I convert it back to 4.88 in both in the future. So what did you mean spend the money and do it right?

 

Well, if you buy an installation kit for either of the axles, including the R&P, bearings, etc., plus a carrier, that's maybe $350 for the kit and another $60 odd dollars for the carrier, plus a lot of time and effort, you're up to around $500 for just parts for the rear axle. That's most of the way to an overdrive. Plus, installing differential gears isn't for tyros - are you up to it?

It seems to me that the one thing you really want is to use this D30 axle. To me, you'd be better off to just hang on to the 30 for now and keep your 27 front axle. Everybody that has the overdrive that I know has been really happy with it.

One possibility is to find a Wagoneer or J-truck 44 axle with 3.54s... there were a lot of them made and you should be able to find one fairly cheap. That could provide your R&P and possibly an open carrier, if that's what you want. The problem here ... and I don't know the answer ... is whether you want to put used parts back in your axle or not. Some people say don't install a used R&P or bearings; I can't offer an opinion. The more new parts you need, the more it will cost.

 

make sure the f/r ratios match. setting up ring/pinion is NOT for the faint heart (difficult to setup w/o specialized tools). would be best to follow tim's advice and save the $$$ and change the dana 30 to 4.88 and get an OD.

 

Thanks cj5 for the input. I plan on keeping the jeep for a long time. So what ever way we go I am sure it will not be the last mod we do to it. I do plan on getting the axils done by a shop. One thing that is neat is all the kids in the neighbor hood want to go out in it. They check by often to check on the progress.