Firstly the vehicle and its current configuration
- Wrangler YJ 87 model with 4.2L AMC 258 engine
- HEI Distributor Kit
- Weber K551 Carb (32/36)
- Slip Yoke eliminator
- New / Stronger Leaf springs all round (slightly raised from stock position)
- 31 Inch tyres
- Assume current diff ratios are 3.07
The main problems I have with the vehicle is the lack of power (revs) in 5th gear (75 MPH and RPM is 1500), the other major problem I have is the internal clutch slave keeps going im assuming that this is because I still have the slip yoke in and the rear prop shaft is a bit short (Shudders when you take off) but in the long run (not this upgrade) I would like to replace this clutch with an external slave.
So back to the Dana's:
After reading countless threads on the Dana 35 strengths and weaknesses, I still have not come to any conclusion as to the route to take when re-gearing the 30 & 35.
There are a lot of recommendations to swap out the 35 for a Ford 8.8 (95 + model) or the Dana 44 because the 35 is a weaker axle, I dont dispute this fact as I have also had an incident with a tooth breaking of the gears in the carrier and jamming up while traveling on the open road, I have been lucky enough to not have a twisted or broken shaft tho.
I currently live in South Africa and have done some research on whats available on the local market, they have a similar differential to the Dana 35 and 44 produced by Gearmax which I understand has ties in to Dana Spicer. (Gearmax Mod 89) apparently this differential can be fitted for quite cheap but I have not yet had the opportunity to confirm it with them. It also apparently comes with a locker.
There are two approaches that I could take
The initial approach I was going to take: re-gear both ring and pinion sets to 4.56, and I understand this requires a new carrier. Does this mean that the whole carrier, gears, bearings and all need to be replaced? and can I still use the same shafts for the front and rear axles?
A rear replacement: The other option is replace the rear axle with a Ford 8.8 (Slightly shorter), or a Gearmax Mod 89 (6 Stud so need a 6->5 adapter) and still change the Dana 30 ratios and carrier.
The other questions I have are around the ratios and I worked out on this site
Gear Ratio Calculator
that the 4.56 would probably be best, we dont do any serious rock crawling or take the vehicle on any long trips purely because it is regarded as unreliable (Family prefers Toyota LC's in Africa).
Is 4.56 the correct ratio to go for, and if so what would be the cost involved in replacing the carriers. the site here in SA with the 4.56 will be able to supply the ring and pinion at USD 376 each.
Dana 35 4.56 ratio
I hope to get this sorted out in time for the xmas break as it will be fun to prove the Toyota drivers wrong when we go on our next trip.