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Another thing that should be included in your gear selection would be tire diameter. The way I see it, tire size should be the minimum you need to do the trails that are in your area. With a 3.45 diff ratio, should put you in good shape for highway driving and moderate trails with a 31" diameter tire to start with.
Currently running 33's. Hills and mild rocking, nothing technical. Just trail riding etc. I was looking at changing the Dana 20 over to the 3 to 1 but the kits are a few hundred higher than the Dana 300 and the 4 to 1. But I would have to buy the adapter for the Dana 300 . The Dana 300 a 3 to 1 already?
Another thing that should be included in your gear selection would be tire diameter. The way I see it, tire size should be the minimum you need to do the trails that are in your area. With a 3.45 diff ratio, should put you in good shape for highway driving and moderate trails with a 31" diameter tire to start with.
84 CJ7 4 banger-owned since new in 1984 bought off truck at dealership - rebuilding 258, T176 with Sniper EFI D300 4:1 Lomax gears Twin Sticked 1 piece axels with locker
84 CJ7 4 banger-owned since new in 1984 bought off truck at dealership - rebuilding 258, T176 with Sniper EFI D300 4:1 Lomax gears Twin Sticked 1 piece axels with locker
Mine came new 33 years ago with AMC 2.5 4 cyl with T-4 & Dana 300 . Can't say I've really had any problems with that combo and at the time that's all I could afford. My buddy had just gotten the deluxe combo package and spent 1 1/2 times as much. After a few years of struggling with the AMC carburetor I put a Webber on and that really made a huge improvement. Then a few years ago I installed a MSD AL6 and now it runs far better than new. I now have over 235 K miles and It runs great but I know it won't last forever so I've found a 6-AMC 258 i6 / 4.2l and sent it out to the machine shop and sometime in the future will install that with a better Transmission and plan on doing the 4 to 1 in my Transfer Case . I would like to go with a T-18 -T19 or NP 435 but I know that is not really to practical so it might just be a T-176 . Since my jeep runs great I'm not in any rush so this is a good long turn project I don't have to be in a hurry about
This is what you would have if you went with the T-18 with 6-1 first and a 4-1 Dana 300 .
1st gear ratio (6....) X low range ratio (4) X differential ratio (3.55) =85 +/-
Assuming you currently have something in the 3-1 range (T AMC 150 ) and 2-1 (Dana 20 ) with 3.55 diff gears your ratio currently is 3x2x3.55=21+/-
I'm currently at 54, but I still have 2:73's. It's a huge improvement over the stock ratio 28, but it's still faster than I would like in rocky sections. I dont go seeking rocks just for the thrill of saying lookie what my Jeep can do, but they come up sometimes in the pursuit of solitude in the desert and beating the out of my Jeep isnt my thing. Not to mention, the faster you go over rocky sections just shakes up your beer.
That is an interesting calculator there, Bass, I even played with it awhile. I do not think it compensates for the actual tire diameter though, as those charts never do, which can vary. For example my 33" tires at 27 p.s,i. is probably around a 31"-32" diameter with the Jeep weighing it down for a good ride and good tire wear. I used to run 35s, but they were a bit much for the AMC 258 i6 / 4.2l to push around even with 4.10 gears.
That is an interesting calculator there, Bass, I even played with it awhile. I do not think it compensates for the actual tire diameter though, as those charts never do, which can vary. For example my 33" tires at 27 p.s,i. is probably around a 31"-32" diameter with the Jeep weighing it down for a good ride and good tire wear. I used to run 35s, but they were a bit much for the AMC 258 i6 / 4.2l to push around even with 4.10 gears.
I think you're right Torx, I don't see how a crawl ratio can be calculated without factoring in the tire diameter, but it did get me the crawl ratio that I was looking for when I used it.
Ok, I don't know if this can be answered here, but here goes. I found another T-18 from a 1988 4x4 f150. Good shape, 110 miles on the Transmission . It has the PTO on the passenger side and according to the seller contains the granny gear. Can I swap those gear from the 1988 T-18 to my 1976 Jeep T-18 while retaining the 1976 Jeep T-18 input shaft?
Ok LG. I combed over those diagrams before, but it would help to know what gear is what. I'll take a guess. First gear would be the large diameter gear closest to the output shaft right? So if that is correct, then they would numerically count down, 2nd then 3rd then fouth towards the input shaft right? So the small gear on the input shaft would be 4th gear at 1 to 1?
I personally am not sure if parts from an 88 will fit right into an earlier case, but the guys at Novak can help you with some of the technical questions about tranny's.
'85 CJ-7, 258/4.2L 6cyl. Bought new in 1985. Full cage, Warn 8274 winch, Ford 9" rear, front/rear Detroit Lockers w/4:88 R&P. T-5 tranny and 4:1 t'case. 33X12.50-15 BFG/AT, MSD ign, on board air---
Ok LG. I combed over those diagrams before, but it would help to know what gear is what. I'll take a guess. First gear would be the large diameter gear closest to the output shaft right? So if that is correct, then they would numerically count down, 2nd then 3rd then fouth towards the input shaft right? So the small gear on the input shaft would be 4th gear at 1 to 1?
I'm sorry I'm not comprehending or understand what I am looking at on the diagram. It's my lack of experience on how the parts work together. Something I'd like to remedy.
I think I have finally worked out an idea of what I'll do here. Tell me what you think.
I want to use the Jeep T-18 I have with the 4.02 first gear. I am going to use the Dana 300 and put in the 4 to 1 gear kit. I used the crawl ratio calculator on Novak that was linked here. The 4.02 T-18 with the 4:1 Transfer Case and my 3.54 gear ratio gives me a C.R. of 57:1. The 33" tires will probably knock that ratio down a little, but should still be above 50:1. But I think it will be a street freindly trail friendly combo.
It's probably here somewhere, but I'm too tired and old to dig back through all these posts, is the T-18 already adapted to fit the 300? If not it can be done, it's expensive. With your understanding of transmissions adapting the Transmission AND adding a 4:1 gear set to the 300 will be a huge learning experience. ..... or with deep enough pockets you can pay someone to do it.
IIRC, I paid $500 +/- for the adapter kit for T-18 /19 to a Dana 300 from Novak a few years ago.I also got the complete rebuild kit from Novak for my T19 for another couple hundred, I figured I might as well do it all right while its apart. $750 for Lomax 4-1 kit. I was into the whole thing for $15-1600 with me doing the work. I got lucky that the T19 with the adapter was the same length as the T-5 I was replacing, so the driveshafts didn't need to be cut down/lengthened.
I have been pricing things out. I found another adapter supplier that is a little less expensive. I can get a 4:1 kit for the 300 for $650 and the gasket kit for $35. Advance Adapters offers salvage conversion kits in the low $400's.
I'd like to use the T-18 and Dana 300 I currently have but doing so will require a drive shaft cut and lengthen as it's over 3" longer than my T-150 and Dana 20 . So there is another added expense. I am searching for a good 435 also. It by the numbers seems like the best route. I am not sure if drive shaft mods will be required but there are shops locally that can do it.
I just sat back and decided to take my time, to make sure what exactly I want to do. I did do a little trail riding to the extent that it showed me that I do need the crawling gear. There is no doubt about that.
It's probably here somewhere, but I'm too tired and old to dig back through all these posts, is the T-18 already adapted to fit the 300? If not it can be done, it's expensive. With your understanding of transmissions adapting the Transmission AND adding a 4:1 gear set to the 300 will be a huge learning experience. ..... or with deep enough pockets you can pay someone to do it.
To answer that, no it's not. It has a Dana 20 mated to it. I looked at the 3:1 kits for the Dana 20 and they are crazy expensive. If I change any gearimg, it'll be the Dana 300 . Cheaper and better results. The setup the T-18 and Dana 20 came out of was an inline6 with 3.73 gears.
I know it'll be a learning curve, but it is something I'd be interested in learning to do.
out of my Jeep isnt my thing. Not to mention, the faster you go over rocky sections just shakes up your beer.
