L-Head to SM420?

Just starting to research the possiblity of adapting an SM420 to my beloved L-head, so I thought I'd start here... I realize anything is possible with enough time and money, but what's the skinny on this combo?

 

I'd guess that the factory F134/T-98 setup would satisfy most people that want a 4-speed with a 134. Bolts up to the L-head too IIRC. They aren't plentiful, but you can find them if you look.

 

how would the T98 compare to the T90 in terms of strength and low gearing?

 

The Borg-Warner T-98 evolved into the B-W T-18. Internally there are some differences, but they function the same and have the same gear ratios. Both the T-98 and the T-18 are heavy-duty truck 4-speeds with a compound low gear. You can compare the T-18 to the T-90 here:
http://www.novak-adapt.com/knowledge/transmission_gateway.htm

 

I've spent some time looking for the same thing... (any kind of kit to run a SM420, jeep T18, Ford T18, SM465, whatever) also been looking for the T98A w/ 4 cylinder adapter, no luck so far........

What I've found (as of October 2006).

AA: Nothing available, and nothing planned

Novak: Nothing available, but they thought they might have something in the next year or so.

Some place in Oregon that specializes in adapting Ford T18's into broncos and jeeps (specifically, they sell the adapter and output shaft to fit it to a dana 18 and 20): They said that they had something in the works for the Ford T18 to 134, but expect to wait about a year. I'm trying to remember their name, but I just can't seem to find it. Maybe it will come to me later. Something to do with the words drivetrain and 4wd I think.

I talked to Herm and he said the last T98A, 4cyl, he lucked into went for quite a bit... (over 1k I think he said). At the time (a few months ago) he didn't have any suggestions for adapting anything else for this application.

The problem, as best as I can tell is that most of the input shafts for any of the common grannies are too short; that is, you can't just stick a simple adapter plate between your 4cylinder bellhousing and one of these transmissions. The second problem may be to find a correct diameter clutch disc that has the right splines... I never found a tranny that would work, so I didn't bother to check into that part.

It appears that you may either need a new input shaft, or you'll have to find some rare breed like the T98A that came with the 4cylinders and happens to have this longer input shaft.

Now you might be able to get your 4cyl bellhousing machined to fit one of the common grannies, and then it might work...

I hope you find something readilly available, as I'd love to do the same thing. What I did in the interim, is I spent about $140 on a lower ratio input shaft gear and matching clutster gear set for my T90. It gets you about 20% lower in 1st, 2nd and rev (3.38:1 vs 2.8?:1 I think). That's about the same as 2nd gear for any respectable granny...... which isn't saying much. These gears are available from just about every jeep vendor (I got mine from Herm). One rumor is that they came standard in the 3B's.

 

I have an L-Head/T98 combo and have been pleased with it; the crawl ratio is great. My concern is for the future: if the T98 goes bad, I don't have many replacement parts options of which I'm aware. Nonetheless, if you can find a T98 in good shape, they do work quite well with the L-Heads. (I'd also recommend an overdrive - helps if you have the 5.38 axle ratio in combination with the above setup.)

 

If you need a longer input shaft, the T-18 from a 71-79 Jeep truck, Wagoneer or Cherokee with a 258 inline 6 is reputed to be about 9" in length. Has to be from a 6 though - the ones with the V8 will be way too long. Then you'll still have to make a plate to adapt the transmission to the 134 bell, and figure out how to make the retainer, TO bearing and clutch work.

 

I sort of agree with Timgr. If you had a long shaft T-18, the shaft should be long enough to reach through an adapter and through the stock bellhousing. you might be able to machine the shaft to fit the original clutch disc. Or, get a custom cluth disc if someone does them. The adapter would have provisions to mount the original bearing retainer in the original bellhousing so you can support the original throwout bearing, and you could make or buy (Novak) a bearing retainer for the front of the T-18 to actually hold the front bearing. This weekend I am going to look at some parts I have laying around and see what I think would work.

 

The place in Oregon is R&P 4 wheel Drive Parts Inc. Money and time right now is the issue but it is in the works. I'm working with Richard on this project. Nickmil

 

http://www.earlycj5.com/forums/showthread.php?t=21501&highlight=sm420

 

Talk to Jason Hawkins here on the board, IIRC he found someone local to him that has a source for some input shafts for the T98.

 

I have a ford T-18 in my 2A attached to a F head it is doable best upgrade I ever did.

 

How about some details!

-What year/model truck did the T18 come in (I'd assume F series truck...)
-how long is the input shaft?
-what did you do for an adapter plate?
-what did you use for a clutch disc and pressure plate?
-what did you do for a pilot bushing and throwout bearing/fork etc?
-any other details worth mentioning? (crossmember mods, clutch lever/cable/pivot mods, floor mods, dropped drivetrain? etc, etc)

 

I used a Scout T-18 case with the 18 trancase adapter,Ford 18 internals with the short input shaft and ford bearing retainer ford throwout and clutch arm (modified).Ford 91/4 clutch disk from a early mustang I think,and a Jeep 91/4 pressure plate.Pilot bushing was a stock jeep unit with the I.D. milled to match the ford input shaft.The major part was to have the original bell housing milled down at the trans mating surface,till it was about 3/16 thick,bearing retainer area has to be opened up to match the ford retainer.To attach the bell to the trans I drilled and tapped four holes,and built some thick steel reinforcement areas around to add additional support.My clutch linkage is all hydralic using a newer jeep slave and master.Their is alot of on off things as far as that goes on the slave and clutch arm.But I also have previously installed swinging pedals.My close friend has one of the original setups with the factory T-98 combos and it makes for a much sweeter install.Maybe this helps someone their is a good degree of fab work cross member had to be custom made and I also had to raise the tranny up into the tub a good bit.But I had access to a friend who's a machinist and the original setup to look at.I did this out of want,need and the mechanical challenge.

 

Yep, that's exactly what I'm thinking too. Though I'd rather not reinvent too much if I don't have to.

I got an email from Herm Tilford yesterday, sounds like he has both T98's and T18's with the correct input shaft, the 4 cylinder adapter plates and is working on a kit (with crossmember) as well.

 

I want to install a T-18 to my MB and would like to talk to you.