Project 6

[Posimoto]

I was asked to take some pics of adapting a D-300 to a T-18 so I though I start a build thread.

I just picked up this 79 CJ5 because the price was right and I figured I’d have some fun with it. It’s close to being trail ready as is but I plan to change a few things.

The first thing I’m doing is removing the light duty T-5 tranny and replace it with a CJ T-18 (6.32) I had stored in my shop I’ll use the D-300 that’s already behind the T-5. I will install a 4.1 kit in the D-300 that came new in the box with the Jeep. If I had a set of 44s handy I’d through them under it but I don’t so I will use the D-60s (4.10s) I have in my shop. IMO the 60s are a great fit for my short wheel base plus I only paid $300 for the set. The rear 60FF diff hangs just ¾” lower then an 86 CJ44. I will bore out the rear spindles by .22 and use D-70 1.5 35 spline shafts to replace the rear 60 1.31 30 spline shafts. At this time I’m planning to go with a 35”-36” tire with soa and outboard the springs. My final crawl will be 106.1, I wasn't looking to go that low but as I mentioned the Jeep came with a free 4.1 kit, and well, it is what it is.





I have a few things to play with, 4.1 kit, disc brake brackets, T-18/D300 adaptor. I also picked up a new chop saw with 10 blades.

[mika401]

I've had the same adapter in my T18 for almost 10 years now.
Thats going to be a wiked low ratio

[Mitch]

nice chuck! Will this one have power steering!

[jps4jeep]

Posi = what I aspire to be when I am what ever age posi is.

[jerry k]

posi, that chop saw is the nuggets, i have the same one..

[Posimoto]

I stripped down the rear 60HD to bore out the spindles and add disc brakes. There are different rear 60s out there and I was lucky enough to get the heavy duty rear with added webbing on the diff and large OD spindles. The big spindles have a larger O.D. than the little spindles. The little spindles measure about 1.8" O.D. and the big spindles measure about 1.95" same size as the 14b.

 





Below is the T-18 I’ll use to mate to the D-300. I removed the D-20, adapter, and b-housing.





The first thing you have to check is if the adapter came with the correct 23 spline mainshaft because they make a 27 spline for a Ford T-18 as well.

The adapter has 2 bottom mounting holes that the T-18 does not so I have to drill and tap the case. I installed the adapter with 4 of the 6 mounting bolts and scribed the case. I used whiteout as a base to help ID the marks.



I then removed the bearings and mainshaft. There are 22 roller bearings that will fall to the bottom of the case I happen to find 23, maybe one is the top shift pin or someone could have already been in there. I’ll know more once I inspect the roller bearings.

Bearings, mainshaft, retaining and lock clips




I pressure washed the case about a week ago and didn’t drain the oil/water until this weekend = dirty lube.

[Twisty]

How are you going to bore out the spindles?  What ID do you plan?  Are you going to run 35 spline shafts.   

[Posimoto]

I'm subbing it out to a friend who will do it for much less then the cost of a 1 9/16 (1.562") drill bit, a bit I would need to purchase if I was to do it myself. I will bore the spindles out to 1.6 to except the 1.5 35 spline shafts. This is why you need the larger 60 OD spindles at 1.95, the smaller 1.8 would only leave about 1/8" material after boring.

There are other alternatives although they don't seem piratical to me, find a 70 and cut off the spindles and re-weld them on the 60 or have Mitchell's cut the 60 spindles off, bore, and re-weld back onto the 60 at IMO a high price of $350 (they don't bore the spindle on the axle).

Edit: side note, very few FF 60's came with 35 splines. Most are under chevy van's and are much wider than the rest of the 60's

[jps4jeep]

74-75 ish J series trucks had a semi float 35 spline 60, or am I wrong?

[jps4jeep]

Rich, older chevys had 60 rears, used towards the end of the eaton axles and previous to the Corporate axles

Bcarms on this board had a 2wd 69 (or 70) GMC C20 pickup with a 8 ft step side bed that had a straight 6, unknown tranny and ff d60 rear.

[Posimoto]

74-75 ish J series trucks had a semi float 35 spline 60, or am I wrong?

The correct year for the FSJ 60-2 is 69-73 and it is a 35 spline but my reference was to “FF”.

very few "FF" 60's came with 35 splines. Most are under chevy van's and are much wider than the rest of the 60's

[Posimoto]

I've had the same adapter in my T18 for almost 10 years now.

Did you do the install? If so did you do a write-up? I know you weren't a member 10 years ago but it's certainly possible you posted from a saved write-up.

I did a search didn't find anything. If it's been posted here already I rather not take the time just to duplicated it.

 

[mika401]

Unfortunately it was so long ago doing & posting a write-up was beyond my computer skills at the time.

[Posimoto]

Just a note about removing the mainshaft bearings, they make a bearing remover that slides behind the bearing snap ring that makes removing the bearing a breeze but it’s not needed. After removing the snap ring I used a brass drift working from inside the case to remove the rear bearing. I left the lock ring on the front bearing and used a dead blow hammer on the tip of the clutch shaft to remove the bearing. Both front and rear mainshaft bearings are ball bearing type opposed to the cylindrical or tapered roller bearing.

I next removed the lock plate from the rear of the case that locks the countershaft and reverse idler gear shaft. I tapped out the countershaft to the rear of the case using a brass drift once the shaft was out I was able to remove the countershaft gear assembly. The countershaft assembly has 88 roller bearings and the reverse idler has 74 bearing rollers.

The reverse idle gear shaft does not come out as easily as the countershaft because the front of the shaft is located inside the case unlike the countershaft that is on the outside of the case. I used a long extension and dead blow hammer.

Note the magnet at the bottom of the case it’s a well thought out option. 



I cleaned the case for a second time and chased all threads as well. I used a 5/16 bit and drilled 2 holes for the adapter.



After cleaning the burs I tapped the hole using a 3/8” 16 tap. You can drill a hole in a block of wood and use it to keep the tap going in straight I chose to use a torpedo level it worked for me.

I test fit the adapter and all holes lined up perfectly.



I cleaned the case of metal filings, washed, and prepped for paint.



 

[Bradman]