Which way would you go?

[Grantshire]

The 79 Cherokee Chief I just bought has a built 360 engine with a lot of power, 3.54 WT axles and 35" tires. It also has a QT with the MileMarker part-time kit and 16% OD (major yuck on the OD!). Something has got to change! I like a part-time TC for my 4 wheeling (no rock crawling here) so I am thinking I am headed for either a TC, transmission, or TC & transmission change (maybe also a gearing change down the road). Which way is the best (and most practical) way to go? I could find a GM TH400/205 combination, and have the guts swapped out (I am not a transmission mechanic so this may be major $). I could buy a GM adapter/flex plate kit for about $350 and just bolt up the GM TH400 and just have to make drive shaft adjustments. There are other jeep transmission/TC combos I could use but I have to have one for a passenger side front differential, and there may be others options. One issue that does not worry me is the gas tank problem when using a non-offset TC. My Chief has an auxilary tank tucked under the back where the spare used to fit. If I have fitment issues with the driveshafts (vehicle is lifted 4-6") after the transmission/TC swap I will remove the stock tank and use just the auxillary.

Anyway, that's where I am. With the current setup this thing is a major dog. If this were yours, which way would you go on this? Dollars are a consideration but so is the quality and performance of the swap.

Thanks for you input.

Grantshire
November 26, 2003

[joe]

Trans swap won't help they all have a 1:1 high gear. Your big prob is the axle gearing and the 16% OD in the tcase makes it worse. Your PT QT w/OD can prolly be traded straight across with someone who has a stock unit and wants OD. Using 30" as srock tire size and 34" as the real dia of your tires for calculations and w/the 16% OD you now have an effective axle ratio of about 2.62 :( plus the weight of the 35's causing even more power loss. For a performance gain new axle gears will net you the most power. I'd lose the OD too since it also applies to the LO range in the tcase.

[tgreese]

I'd agree w/ -joe; Swap for a stock QuadraTrac is the most cost effective. Surprisingly, Novak recommends the Dana 18 as a part-time swap for the QuadraTrac. Dana 20 would work too - apparently the driveshaft angularity from the offset rear axle isn't a problem. Some controversy re this though. The D20 low range isn't as low as the D18 or QT though, ca 2.03 v. 2.42. D20 and D18 can have lower gearing, only requiring $$.

All those other combinations seem overly complicated to me. I'd switch to a stock QT, then think about 4.09:1 axles (or ring&pinion).

[Smooshy]

I would go R&P swap... probably around 4:10:1 or up

[Smooshy]

Cool site for gear info http://www.4lo.com/calc/geartable.htm

[Smooshy]

The same site has a cool calculator at the top of this page: http://www.4lo.com