I just got a 91 Dodge (first ever Dodge). It has a 318 with a 4 spd w/granny low gear transmission. I love the granny gear, especially in 4 low, but the jump between gears from 1st through 3rd sucks while driving on the highway, especially when towing. I was thinkg of putting a 5 speed in the truck, which is probably going to be longer and I have to worry about maching the splines on the shafts. The truck is on 33s and has 3.55 gears. I was thinking that with the overdrive in the 5 speed I could put lower gears in the axles and still have a higher final drive ration in 5th gear than I do now and more pulling power through the rest.

Any suggestions, advice, or better ideas would be greatly appreciated.

 

There is a give and take that is very hard to overcome. Having low, mid, and high end performance is a very tall order. Without talking specific tranny models this discussion can only be theoretical without being very helpful. What 5 speed trannys are you considering and what 4 speed do you have? Is this a half, 3/4, or full one ton truck? How are your front axles locked in? You may be able to use a 2 wheel low for hard surface towing.

 

The truck is a half ton. You don't have to lock the front axles just put in four wheel drive. I has the left axle disconnect I think? I saw a swap on 4x4 extreme and he said that is what it does. I was thinking of maybe a T5 transmission. I don't know that much about Dodge, there me be another transmission that will work better and go in easier. Just something that is reliable and won't take too much work to put in. I don't know which transmission I have specifically. Just that it is actually just a 3 spd w/granny low.

Thanks for the reply!

 

I would think the T5 is a bit of a light duty tranny for what you are talking about. This may help you to know what is out there and to ID your tranny.

http://www.motivegear.com/tech_info/...nny_guide.html

 

Hey, thanks for the link. Mine actually looks most like the Muncie. It probably isn't though. Mine has the pto covers on both sides and is shaped the same as the muncie. I think that GM built the Muncie??

The T5 I was thinking of getting is one of the aftermarket units that are capable of 500 ft-lbs. I just don't know how much trouble it would be to put one in the truck. My truck's setup looks factory, but it seems weird to me that they put that transmission in a 91 model truck.

 

Share a link to the tranny you are looking at. I am always interested in learning. As far as I know the max vehicle weight recommended for the T5 is 5500 lbs. With your trucks weight that doesn't leave much capacity for towing/hauling anything.

http://www.ttcautomotive.com/english/products/T-5.asp

 

Your 4 speed should be a np435 i would think. Yea the shift gaps can suck, but good luck breaking it!

 

Thanks for the info. I will get up under there and check it out; see if I can find any information on it.

Seal, where did you find that pound capability of the T5? I would like to do more research into which transmissions can handle what.

 

Here is one source. They are reputable and well known.

http://www.ttcautomotive.com/english/products/T-5.asp

 

I would consider swapping in a nv4500 out of a later (2nd Gen) dodge. They are extremely tough, offer a low first gear for towing/4wheelin, and has the overdrive for the freeway.