Build Thread Best Tranny For The DD

Build Thread Best Tranny For The DD

Iron Duck

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Location
Clarksburg, PA
Vehicle(s)
CJ 7, 150 AMC 4 cylender, T5 tranny, Stock gears, transfer case, and Diffs.
O.K. I own a 1985 CJ7 Renegade that had a GM 151 4 cylender Dana 20 rear & Dana 30 frount 410 gears T-5 tranny. I put a AMC 258 i6 / 4.2l I6 in and a nother T-5 tranny. I am being told that a T-18 is the best tranny to go in a Jeep but I fear that the 4 speed may be good for rock crauling but not so good for High Way travle I drive about 30 miles to work every day and need as good of gass milage as I can get at $3.77 pre gal. I do some off road but becouse I use mine on the road I don't beat it up to much. Sugestions??? thanks
 
O.K. I own a 1985 CJ7 Renegade that had a GM 151 4 cylender Dana 20 rear & Dana 30 frount 410 gears T-5 tranny. I put a AMC 258 i6 / 4.2l I6 in and a nother T-5 tranny. I am being told that a T-18 is the best tranny to go in a Jeep but I fear that the 4 speed may be good for rock crauling but not so good for High Way travle I drive about 30 miles to work every day and need as good of gass milage as I can get at $3.77 pre gal. I do some off road but becouse I use mine on the road I don't beat it up to much. Sugestions??? thanks


For you the best tranny would be the Chevy version of the NV4500
It has a Granny low & Overdrive , but they don't come cheap.
Check the ratio spread.
I drive a T-19A 6.32 & 4.56 gears in my DD, but with 38" tires I only hit about 2750rpm at 70mph, that's the same rpm as my old 280Z 5speed at 70mph.
Granted my rig is no economy machine, but I'm just talking ratios & rpms

Having a low 1st gear allows you to run a highway gear in your axles.
Or bigger rubber if your so inclined.
I mean gear ratio is gear ratio don't hung up on Overdrive .
If your CJ had 2.73 gears like a lot of 81-86 CJ's a T-18a with a 6.32 low gear would be a big improvement.
Plus the T-18 , T-19, T-98 , NP435, SM465, SM420, & NV4500 are all bulletproof.
I'll now dismount my soapbox.:rolleyes:
 
If you dont beat the hell out of your Jeep than the T-5 will hold up fine. My ex wife wheeled her T-5 , 6 cylinder CJ7 with 31 inch tires many times and we never had an issue with the tranny. She even ran it at several Jeep Jamborees in Moab utah running Gold Bar rim, Poison Spider Mesa and climbing Lions Back several times. I never even worried about it. The T-18 is a better, stronger tranny but it is rough around the edges with clunky shifting and hard to find third gear (at least mine is that way). The T-5 is smooth and easy to use.
 
I wouldnt replace it till you break it :chug:
 
Thanks, The NV4500 is a good sugestion and the idea of not fixing it till it's broke is as well. Again I state that I have 4.10 gears so I'm not shour about low gear 4 speeds but the RPM's look good. I may take both sugestions and look for a NV4500 for the write price and keep it on hand for when I may need it. the T-5 that I had for the 4 cylender was solad and smooth there was nothing wroung with it. It just had the wroung spline For the I6. If all else fails I still have the old one and that means I have rebuild parts. Nothing is cheep when you need it Now! But having time to shop around I may find a good deal on a good fit for my situation. If you have any other Ideas I would love to here them I don't have much knolage about trannys so I am willing to learn. I never heared of the Prob. that was mentioned about theT18 are you shour your sink. isen't going bad or that litle peace of plastic at the top isen't broken and binding on you in 3rd gear?
 
It doesnt bind going into third at all. It's just a very old clunky truck transmission that I am sure could use a good rebuild. Someday after my Scrambler is restored I will tackle that job as well.
 

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