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TF 904 for 79 CJ-5?????

7K views 15 replies 7 participants last post by  yjjuggy 
#1 ·
Okay this is going to be kind of a long post and I apologize for the length of this post. I’ve done the searches and can’t find an answer to this question. However, I really need some advice and input from anyone running an AT in a CJ-5 or anything else for that matter that will provide me with any insight into this swap. After 23 years of having a manual (T-150. T-18, SM-420) in this Jeep its time to switch to an auto. I know basically nothing about autos and what little I know is about THs.

I’ve got a 383 SBC in my 79 CJ-5 w/ SM-420/Dana 300 4:1/RC Dana 60. Clearly I don’t have a lot of drive shaft length and would not like for it not to be any shorter than it has to be. I use the Novak adapter from the SM-420 to the D300 (it’s an inch shorter than AA) and I have the short D300 (3.5 inch output). The engine has approximately 430 ft-lb peak torque and a pretty flat torque curve with probably around 300 ft-lb at 2,000 rpm. The current tranny setup measures 30.75 inches from the back of the block to the center face of the output yoke. I have SOA about (5 to 5.5inches of lift), with rear springs shackled front and rear w/four link and no wheelbase stretch. I have pretty good travel therefore a short drive shaft is a critical issue. I can ramp 1000 with open diffs (never tried to ramp it with both ARB’s locked as the airlines weren’t connected at the time).

I want to swap in an automatic tranny. I know the common swap is TH350. The approach that really is interesting to me is to use a Torque Flite 904 that was behind the GM 151 4 cyl. Iron Duke in the the 1980-1983 CJ-7s is especially interesting to me for two reasons:

1. It bolts directly to a SBC and Dana 300 without any adapters.

2. It’s short at 16 inches (but don’t know the tailshaft housing length)

At the 2001 ARCA Finals at Farmington, a brown CJ-5 that was competing had an AMC 360 with TF 904 and an Atlas II. The owner told me he had moved the rear axle back 2 inches and of course it had to run a fuel cell in its bed. Unfortunately, I didn’t get a chance to measure the overall length of the tranny and transfer case. According to the video of the 1999 Johnson Valley rock crawling event, Mike Vokoun’s (I believe he was Joel Randall’s spotter) 1980 CJ-5 is running a TF 904 behind a SBC TPI. I think also that Joel Randall at one time had a 904 in his old CJ-5 but I’m not sure. I don’t know how to get in touch with either of these guys to ask them about their setups. One of the guys in my Jeep club ran a TF 904 behind and warmed-up 350 and after it breaking twice he went to a TH-400 in his CJ-5. But as I recall he didn’t really build the TF 904 either.

I have been told by Turbo Action in Florida, a shop that supposedly did TF’s for Chrysler backed factory drag racers, that they have built TF 904’s that can live behind a hemi. I have been told by others that even built TF 904’s can’t handle the stress of rock crawling. Turbo Action suggested their forward pattern manual valve body which has compression braking in first gear, 5 pack built clutch pack from TF 999, Kevlar bands, built converter, deep pan, and TF 999 2.74 first gear. Turbo Action thinks they could build a TF 904 that can live for me. We talked about the high temperatures in the desert and lack of flowing air encountered during rock crawling and interestingly they thought I should use an air conditioning condenser for my AT cooler. They said if the transmission pukes I can easily wash out the large diameter tubing out whereas the other types you can never really get clean. Is anybody running an AC condenser with there AT? It kinds of concerns me that they even mentioned the AT puking - I don’t know how to take the comment.

According to Advance Adapters the TF 727, 904, 909, and 999 have a case length of 16” which is the shortest of any automatic I know of that is a possible for a CJ-5. On a previous PBB thread I got the length of a TF 999 as 22.5 inches for a 2000 TJ and I assume that includes the tailshaft housing. However, I still don’t know if this tailshaft length has been constant throughout the years for 727s, 904s, and 999s and the numerous transfer cases behind them..

My questions are:

1. Since the TF904 w/Dana 300 was in 80-83 Jeeps with the 4 banger Iron Duke I think I can use the factory tail-shaft housing between the transmission and Dana 300. Is this true? What is the length of this tail shaft housing?

2. How can I identify the transmission by any numbers stamped on the case?

3. What do I use for a flex plate and torque converter for the TF904 to 86-up SBC swap.

4. I assume there is no front driveshaft interference since the TF904/Dana 300 was a factory combination. Is this a good assumption?

5. What can I do about the kick down linkage? I am running an LT-4. A while back an acquaintance of mine built a kick-down linkage for a TF999 behind a TPI SBC in a CJ-7 for one of his customers. He said it was a nightmare to fabricate and charged $800 for it. Should I just use a manual valve body and just forget the kick-down linkage?

6. Turbo Action thinks somebody makes a gear lower for the TF 904 that is lower than the 2.74 for the TF 999. Does anyone have a source for a lower gear?

7. Is there a TF 999 that will bolt directly to a 86-up SBC without an adapter? I think the answer is no, but just had to ask.

Thanks!
 
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#2 ·
I think I can help with a couple of these questions, Il try at least.

the adapter to the transfercase on all the TF trannys ive seen is about 5 inches long.

the kickdown is not a big deal, the guy who charged $800 to fab one is a moron or a rapist, or both.

Ive bought a couple from jumkyards for $20, and if you had to mae one, you could make a better than factory one ( adjustable form the driverseat) for about $30

basically it pushes a valve in the tranny dependant on throttle pressure this controls when and how hard itll shift.
the more the throttle pushes that lever to teh trans the longer its held n lower gears, and the firmer the shifts are.

less pressure = top gear at 10 miles an our, slushy shifts, and almost no downshifting.
 
#4 ·
This must be one of the stupidest or simplest question posted since most just look at the post and don't have any input. Is that the case or is it just an obscure technical question?

Thanks ozarkjeep and OTTERGONEJPN for you input.

Please Help Me!

P.S. "guy who charged $800 to fab one is a moron or a rapist, or both"

He is niether, I am not going to mention his name, but he is one of the top fabricators in our sport and highly respected. I have NEVER heard a bad word about this individual. I think it was difficult due to the throttle position sensor but not sure.
 
#5 ·
can't offer to much info but I am going to swap a 727 in my friends jeep. We got the entire setup at a pick and pull for 85 bucks + tax. We were going to go with a 904 but didn't because it had to be built. I have researched lots of people who have done it successfully. the 904 and the 727 are direct bolt ons to a dana300 just get the correct tailshaft. I can't help you on the length but with a 727 and a long output shaft dana 300 our drivetrain is only going to be 3 inches longer.

Im not sure on identification of the 904 but if there is a choice it is the smallest one. For example and these are random numbers the dimension of the center of tranny (around the planetaries) is like 10 inches in diameter adn the 727 is like 18 so it is small compared to the others. There is no driveshaft clearance problems with the 904


arndog
 
#6 ·
Thanks arndog.

What motor are you putting the 727 behind?

I am sure that you are aware that with the 727 there is a front driveshaft clearance issue with the tranny. You need at least a 4" lift to clear the driveshaft and avoid interference.

What is the present tranny/x-fer case that that the 727/D300 is 3 inches longer than?
 
#7 ·
Yep sorry I wasn't more complete. We are going to use the 727 because there are no adapters required as you state for reason to use the 904 (chevy to jeep tranny). the 727 is going behind a 258 and bolting to a dana 300. The present setup is a t-176. I am pretty sure this measure in total (bh, tranny, adapter) at 21 and the new combo is 24. the jeep is sprung over and I plan on notching the pan for the clearance.

We actually pulled the tailhousinng off of a 904 at the yard

arndog
 
#8 ·
arndog,
Thanks for the dimensions, that chceks of one of the important questions I had. Good luck on the swap.
 
#9 ·
nobody20 said:
This must be one of the stupidest or simplest question posted since most just look at the post and don't have any input. Is that the case or is it just an obscure technical question?

Please Help Me!

SIZE=4]Now I'm Beggin for Help! [/SIZE]

The remaining questions need an answer:

2. How can I identify the 904 Iron duke transmission by any numbers stamped on the case?

3. What do I use for a flex plate and torque converter for the TF904 to 86-up SBC swap.

5. What can I do about the kick down linkage? I am running an LT-4. Should I just use a manual valve body and just forget the kick-down linkage?

6. Turbo Action thinks somebody makes a gear lower for the TF 904 that is lower than the 2.74 for the TF 999. Does anyone have a source for a lower gear?

7. Is there a TF 999 that will bolt directly to a 86-up SBC without an adapter? I think the answer is no, but just had to ask.

Thanks!
 
#10 ·
lokar makes a kickdown cable for tf trannys, I guess maybe the throttle is differnt on a FI sbc since you seem to think the guy was justified with $800 for rigging one up)

it might very well be that difficult, Im not real fameliar with a FI sbc, but it seems the factory GM setups used a "TV" cable, from what I remember about adjusting one, if the other end is removeable from a gm tranny that could be made to work as a tf kickdown linkage.
 
#11 ·
Just throwing this back to the top hoping somebody will be able to answer remaining questions.
 
#12 ·
Does anybody know how I can get in touch with Joel Randall or his spotter Mike Vokum? I think they are both running 904's behind SBC.
 
#14 ·
Using the 420 in another Jeep.
 
#16 ·
one thing is do valve body work it doesn't flow fluid in pakr it needs more pressure for extreme use i built a tf for my buggy there cheap as a a turbo 350 and 400 to build its cheaper than 700 or 4l60e witch is a computerized 700
 
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