transmission choice question

[signgrafix]

The 3 speed manual I have in my CJ5 jeep had recently been gone through and is in great shape. Here is my question, I am re-building the jeep from the ground up. I am not that familiar with the transmissions, Is something that you would upgrade from? My plans from the jeep is street and jeep jamboree trails. No rock crawling or anything that is going to tear of beat it all up.

 

[John B]

what year of cj-5 do you have?

 

[Bounty__Hunter]

I would get away from the 3spd, 1st gear is tall and the ratios are pretty far apart. Look at a good 4spd and with a granny low 1st if you can make it work with your engine/transfer case.

 

[signgrafix]

what year of cj-5 do you have?

1978. It was completly gone through a while back by a transmission friend of mine. I THOUGHT it had a chain in the transfer case because you could hear something popping when I took off. he tore it down, called me and said I got some good news and bad news. Good news is, I went through and rebuilt your transmission, bad news, it has no chain, and I don't know what is making the noise. I guy was walking by when he was talking and told him to check the rear axle (2 piece) turns out, that is what is was.
I probably do need to upgrade. I will probably be sorry if I don't. I just hate to give up a trans that I know is in good working condition.

 

[Saddle Tramp]

A stock 1978 CJ5 will have a T150 transmission and a Dana 20 transfer case. Both are strong boxes. The only real problem with the combo is the low range gearing. Even if you don’t want to risk body damage there may be times when you will want a lower first gear. My suggestion is to trade out the T150 for a T18. The T18 was a factory option in 1978 behind the I6 so this swap can be done without any aftermarket adaptors or hacking and whacking to your jeep. The only modification you will need to do is to your drive lines, back one shorter and the front longer; in fact even your bell housing and clutch remains the same.

The bell housing on a 1978 CJ is pre-drilled for both the T150 Ford “butterfly” pattern (for the T150) and the CJ T18 so either a CJ or Ford version can be used. The Ford version will need an adaptor and shaft change at the back but on the CJ version no changes are required as the adaptor is part of the transmission.

My 1978 CJ5 had the stock T150 mated to the Dana 20 with 4.56 gears in the pumpkins when I got it. It was ok gearing wise but I always felt like I needed to shift up one more time after I got to third gear and to drive down the road at 60 mph the motor is screaming a little harder than I like. I now have a CJ T18 with a Scout Dana 300 which gives me a low crawl ratio but still does nothing for the pavement rpms. I‘m considering putting in a TeraLow 4:1 kit in the transfer case (if they still make one) and bumping up the gears in the differentials to help improve the road manors.

Take a look at this link as it has a lot of good information.

http://www.jeeptech.com/convtrans/cjt18/


If you decide to make a change, you should be able to get a least $250 for your T150, maybe more, just put it on Craig’s List. And by the way, change out the axels in the AMC 20 rear-end asap. Those two piece bad boys will break loose when you least expect it, even in the Wally World parking lot, let along the trail, and leave you stranded where you sit.

 

[Rubiconrich]

I too have a Scout TC 146 AKA Dana300 you need the bull gear off a T19
300-8-11 AA sells them. And it bolts up to a Jeep T18

 

[signgrafix]

A stock 1978 CJ5 will have a T150 transmission and a Dana 20 transfer case. Both are strong boxes. The only real problem with the combo is the low range gearing. Even if you don’t want to risk body damage there may be times when you will want a lower first gear. My suggestion is to trade out the T150 for a T18. The T18 was a factory option in 1978 behind the I6 so this swap can be done without any aftermarket adaptors or hacking and whacking to your jeep. The only modification you will need to do is to your drive lines, back one shorter and the front longer; in fact even your bell housing and clutch remains the same.

The bell housing on a 1978 CJ is pre-drilled for both the T150 Ford “butterfly” pattern (for the T150) and the CJ T18 so either a CJ or Ford version can be used. The Ford version will need an adaptor and shaft change at the back but on the CJ version no changes are required as the adaptor is part of the transmission.

My 1978 CJ5 had the stock T150 mated to the Dana 20 with 4.56 gears in the pumpkins when I got it. It was ok gearing wise but I always felt like I needed to shift up one more time after I got to third gear and to drive down the road at 60 mph the motor is screaming a little harder than I like. I now have a CJ T18 with a Scout Dana 300 which gives me a low crawl ratio but still does nothing for the pavement rpms. I‘m considering putting in a TeraLow 4:1 kit in the transfer case (if they still make one) and bumping up the gears in the differentials to help improve the road manors.

Take a look at this link as it has a lot of good information.

http://www.jeeptech.com/convtrans/cjt18/


If you decide to make a change, you should be able to get a least $250 for your T150, maybe more, just put it on Craig’s List. And by the way, change out the axels in the AMC 20 rear-end asap. Those two piece bad boys will break loose when you least expect it, even in the Wally World parking lot, let along the trail, and leave you stranded where you sit.

Thanks for the info. Forgive me for my ignorance, but are saying that I can use the same transfer case? Also, I have a pair of solid Mosier axles if I decide to keep the Dana 20 rear. I am wanting to upgrade to a Dana 44 wide track.

 

[Saddle Tramp]

I too have a Scout TC 146 AKA Dana300 you need the bull gear off a T19
300-8-11 AA sells them. And it bolts up to a Jeep T18

Good point Rich; not long ago no one made the bull gear so if you didn’t get it with the transfer case you had nothing.

 

[Saddle Tramp]

Thanks for the info. Forgive me for my ignorance, but are saying that I can use the same transfer case? Also, I have a pair of solid Mosier axles if I decide to keep the Dana 20 rear. I am wanting to upgrade to a Dana 44 wide track.

Yep, you can use the same transfer case as it will bolt right up but you will need to fab up some extensions for your sift rails on the case in order to keep the stick in the same place on the floor. Not hard to do though. Axle width won’t be a factor here. I'd put the Mosiers in asap and worry about the new rear end later.

 

[signgrafix]

Yep, you can use the same transfer case as it will bolt right up but you will need to fab up some extensions for your sift rails on the case in order to keep the stick in the same place on the floor. Not hard to do though. Axle width won’t be a factor here. I'd put the Mosiers in asap and worry about the new rear end later.

The axles is not an issue right now. I have the jeep tore down to the frame. Pull the rear end and the gas tank, and it will be just the frame. I just fiqure if I am doing it, I will regret not making the change now.

 

[Rubiconrich]

I took out my Dana 20 today. 5 bolts and took off the T18 Bull gear.
I put on the T19 Scout 300 bull gear. I replaced it with a Scout TC 146 Dana 300 and only used 4 bolts. The Scout 300 does not use the bottom hole.