3.54 diff

[LRover74]

OK what is the simple answer. I have a series 3 with original 4.7 diff.If want to get higher gear diff 3.54,because of upgraded engine ,what is the easiest/cheapest way to accomplish this? Thanks a bunch.

[yorker]

109 or 88? 3.54 diffs are a dime a dozen right now, you should be able to find them just about everywhere. Stock they aren't that strong but neither are 4.7s...

[willincalgary]

I would say a cost effective way to accomplish raising the gear ratios while maintaining your offroad, low range performance would be to install an overdrive. Changing the diff ratios would accomplish the goal of increasing the gearing but would make going slow offroad more difficult. Likely more expensive to change both diffs then install an overdrive.

[LRover74]

It is an 88. Where can the 3.54 diff be sourced ?It is 10 spline i believe. What year RR.

[yorker]

It is an 88. Where can the 3.54 diff be sourced ?It is 10 spline i believe. What year RR.

Every year up to ~'93 or so when they went to 24 spline. I have known several people why have scrapped them recently- check eBay, local scrappers etc. A used one shouldn't cost you much more than $50-75 IMHO.

[TeriAnn]

Every year up to ~'93 or so when they went to 24 spline. I have known several people why have scrapped them recently- check eBay, local scrappers etc. A used one shouldn't cost you much more than $50-75 IMHO.

As he says, check your local wrecking yard for early Rangies. I'm assuming you want to keep things on the cheap and you don't care if you lose your low off road gearing.

If off road gearing is of interest to you and you have a little more $$$ to spend you might consider a high ratio transfercase conversion. The high range gearing is very close to that of 3.54 R&Ps and you keep the stock low range gearing. It is the best of both worlds.

You upgraded your engine. What did you put in and about how much power do you think you are getting? Did you swap in a stronger gearbox??