Best approach to lowering gear ratio on a dana 44 (3.75) for wheeling.
- Thread starter Dana44
- Start date
- Joined
- Jan 11, 2015
The truck 4spd is definitely an improvement. It's a lot of work and some expense, Adapters, driveshafts etc. That coupled with a set of Teralow gears is a great combo because you still have some road gears.
- Joined
- Feb 8, 2021
If you are wanting to build it as a trail Jeep, the T18 is a good choice.
Yours being a 71 CJ5 it should have the stronger flanged 19 spline rear axles, which were only in production a little over a year, and are hard to find. These are much stronger than the two piece 10 spline axles of earlier CJ5s.
If you want an even stronger rear axle, the strongest solution is a Full Float conversion using 30 spline flanged axles. I have a similar Full Float conversion on my trail Jeep, but instead of flanged axles it has Dana 30 hubs with Warn lockouts to make flat towing easier. In that configuration the Warn lockout hubs are the weak point, so I carry a set of Dana 30 drive flanges in my trail bag.
The Jeep came to me with that full float axle conversion, and a Yukon Grizzly locker. I didn't like the on-road manners of the combination of the automatic locker and the softer Holbrook springs on the Jeep, so replaced the Grizzly with a selectable locker.
I liked the Grizzly on trails, and it is a very strong unit. I listed it for sale in the forum classifieds but so far no takers.
Yours being a 71 CJ5 it should have the stronger flanged 19 spline rear axles, which were only in production a little over a year, and are hard to find. These are much stronger than the two piece 10 spline axles of earlier CJ5s.
If you want an even stronger rear axle, the strongest solution is a Full Float conversion using 30 spline flanged axles. I have a similar Full Float conversion on my trail Jeep, but instead of flanged axles it has Dana 30 hubs with Warn lockouts to make flat towing easier. In that configuration the Warn lockout hubs are the weak point, so I carry a set of Dana 30 drive flanges in my trail bag.
The Jeep came to me with that full float axle conversion, and a Yukon Grizzly locker. I didn't like the on-road manners of the combination of the automatic locker and the softer Holbrook springs on the Jeep, so replaced the Grizzly with a selectable locker.
I liked the Grizzly on trails, and it is a very strong unit. I listed it for sale in the forum classifieds but so far no takers.
Well its official. I must have the disease. I am pretty serious about installing the T18.
I can't stand how the jeep is set up now regarding gearing. A great commutor jeep but to go the speed I want, even on flat crop edges and 2wd territory I have to put it in 4lo just to slow it down enough to have any kidneys left.
I can't stand how the jeep is set up now regarding gearing. A great commutor jeep but to go the speed I want, even on flat crop edges and 2wd territory I have to put it in 4lo just to slow it down enough to have any kidneys left.
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colojeepguy
Colorado Springs
- Joined
- Apr 4, 2010
The flanged 44's are 30 spline. The earlier 2 piece axles are 19 splione. Much earlier are 10 spline. I don't remember when the change from 10 to 19 happened.
- Joined
- Feb 8, 2021
Thanks for the correction. I have only owned one non flat fender Jeep and that is the CJ5 in my avatar picture. It is a 67 with 19 spline two piece axles. I think the transition from 10 spline to 19 on the two piece axles was around mid fifties.
I did not realize 30 spline axles were used in Jeep, if that transition was for the 71 year, it would have only been used up until AMC started using their own axles. So, something I had not encountered.
If I learn something new every day, and live long enough, I might know it all someday, but not there yet.
I did not realize 30 spline axles were used in Jeep, if that transition was for the 71 year, it would have only been used up until AMC started using their own axles. So, something I had not encountered.
If I learn something new every day, and live long enough, I might know it all someday, but not there yet.
I bought a Ford T18. Granny low. Its an earlier one according to its tag. I will confirm the gearing when I pick it up this weekend. I want to see inside for sure. Not worried about putting in new synchros and needle bearings etc but do not need a rust bucket.
skipilot
Member
- Joined
- Dec 16, 2007
No on the D41 gears into a D44 and the D41 is a bit of an orphan and hard to get parts for whereas you can get just about anything for a 44.
I am in the home stretch of putting a Ford T19 (basically the same process as doing an T18) into my ‘69. It is time consuming and the trans/t-case is a heavy awkward lump. You will want to check out Fireball’s thread that includes his Ford T18 install that he linked above, I referenced it quite a bit (Thanks Fireball). There are also good threads on people’s 4speed crossmembers and the sheet metal floor covers. There is generally more than one way to do most of this stuff so don’t feel you have to do exactly the way someone else did.
Some other things to consider:
You will probably want to find an earlier bell housing (66 through early 70?) as I don’t believe the longer late ones work with a Ford trans.
If you are wanting to go twin stick, now is a great time. You will either need to source the front parts from any twin stick D18 or build your own linkage.
Do you want to stick with the smaller ujoints the V6 jeeps use or convert over to the standard jeep 1310 size. I switched to the 1310 since I was swapping in a front D30 at the same time, if I were sticking with my D27, I probably would have stayed with what was there.
Good luck with the conversation.
Tim
I am in the home stretch of putting a Ford T19 (basically the same process as doing an T18) into my ‘69. It is time consuming and the trans/t-case is a heavy awkward lump. You will want to check out Fireball’s thread that includes his Ford T18 install that he linked above, I referenced it quite a bit (Thanks Fireball). There are also good threads on people’s 4speed crossmembers and the sheet metal floor covers. There is generally more than one way to do most of this stuff so don’t feel you have to do exactly the way someone else did.
Some other things to consider:
You will probably want to find an earlier bell housing (66 through early 70?) as I don’t believe the longer late ones work with a Ford trans.
If you are wanting to go twin stick, now is a great time. You will either need to source the front parts from any twin stick D18 or build your own linkage.
Do you want to stick with the smaller ujoints the V6 jeeps use or convert over to the standard jeep 1310 size. I switched to the 1310 since I was swapping in a front D30 at the same time, if I were sticking with my D27, I probably would have stayed with what was there.
Good luck with the conversation.
Tim
- Joined
- Aug 10, 2003
Look for "Dana 41 axle gasket."
The 41 is really different.
AFAIK only the 44 and 60 (and maybe the 70?) have that cover shape.
47/8 = 5.875 which is not a usual ratio for the CJ.
If you take the cover off, the ratio, part number and tooth counts are stamped into the edge of the ring gear.
The tag number on that Ford T-18 will tell you something about the transmission.
Google says it's '68ish production.
Early top cover - R right and forward - confirmed.
If I were to refresh this, I'd be tempted to reuse nearly everything if ok.
Gaskets, seals, 2nd & 3rd blocking rings, top cover kit.
Often the sliding gears (1st and reverse) have some rounding, but I would not replace unless badly chipped.
A T-18 is so under-stressed in a CJ that it should run forever if in decent shape.
Unlike the 3-speeds, you'll need special tools to take it apart.
See my thread here about my J20 T-18 - https://www.fsjnetwork.com/forum/viewtopic.php?t=10473
The 41 is really different.
AFAIK only the 44 and 60 (and maybe the 70?) have that cover shape.
47/8 = 5.875 which is not a usual ratio for the CJ.
If you take the cover off, the ratio, part number and tooth counts are stamped into the edge of the ring gear.
The tag number on that Ford T-18 will tell you something about the transmission.
Google says it's '68ish production.
Early top cover - R right and forward - confirmed.
If I were to refresh this, I'd be tempted to reuse nearly everything if ok.
Gaskets, seals, 2nd & 3rd blocking rings, top cover kit.
Often the sliding gears (1st and reverse) have some rounding, but I would not replace unless badly chipped.
A T-18 is so under-stressed in a CJ that it should run forever if in decent shape.
Unlike the 3-speeds, you'll need special tools to take it apart.
See my thread here about my J20 T-18 - https://www.fsjnetwork.com/forum/viewtopic.php?t=10473
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- Joined
- Apr 8, 2008
- Joined
- Nov 7, 2022
Is it me or is that a really long adapter? And the tail piece facing the T-case looks long as well. Pardon my ignorance but what t-case is that?
colojeepguy
Colorado Springs
- Joined
- Apr 4, 2010
Normal for a J truck. They have a crazy long input shaft.
My bad. The tag reads 43/8 or 5.37.
- Joined
- Aug 10, 2003
The V8 J-trucks and wagons with a manual transmission all have that very long input shaft and some long adapter or very long bell housing.
The sixes get a thin plate adapter or a normal looking bell housing.
This puts the shifter the same place in the cabin, six or V8.
The '80-up J-20s with the T-18 also got the long Ford output shaft and adapter to the NP208.
(I presume it's the same as Ford - looks identical.)
Covered more here - https://www.earlycj5.com/index.php?threads/144701/post-1608535
5.375 - the math rule is 'always round midpoints to the even number' ... rounding to 3 digits is 5.38.
Common ratio for the 134 CJs.
The sixes get a thin plate adapter or a normal looking bell housing.
This puts the shifter the same place in the cabin, six or V8.
The '80-up J-20s with the T-18 also got the long Ford output shaft and adapter to the NP208.
(I presume it's the same as Ford - looks identical.)
Covered more here - https://www.earlycj5.com/index.php?threads/144701/post-1608535
5.375 - the math rule is 'always round midpoints to the even number' ... rounding to 3 digits is 5.38.
Common ratio for the 134 CJs.
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I marked the input and output shafts and counted revolutions each gear of the input side until the output had completed one revolution. It was easy to keep track that way.
The Reverse gear shows some minor chipping. Other than that, and wear on the edge of the relief at the ball end of the stick shift there really is none to be concerned with.
The Reverse gear shows some minor chipping. Other than that, and wear on the edge of the relief at the ball end of the stick shift there really is none to be concerned with.
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