I'm so disgusted with these weak Torqueflite transmissions that I'm not going to bother rebuilding them anymore. If anything, I'd rather give it to some poor shop mechanic and bleed him dry through a warranty but I'm not that diabolic right now. What do you guys think of bolting a GM transmission to an AMC 6cyl? I'm thinking of getting a TH400 and it might be strong enough to survive my simple distance trips until I can find a manual to put in here. Is there anything I should specifically look for besides the 4WD model?
My dad has a 79 blazer with a stought 355 and a built th400. he bought it in 93 did the motor and had the local shop do the th400 with a coupel of aftermarket improvments. He pounds on this thing still today and the only thing he has done to the 400 is normal mantinance.
All I really ever do with this Eagle is long distance freeway trips over flat pavement and minor hills. The transmission blows up whenever I pass through Vancouver and I'm sick of going through a total panic whenever this thing kills the engine in Portland traffic. I've found a few listings for a AMC/Jeep TH400 on craigslist and I've even found a wagon with one of them but it's bolted to a 360. Will this easily bolt up to an Eagle or will I have to modify something?
The AMC 360 and the 258 share the same bell housing pattern. We seldom hear of catastrophic 998 failures -- mainly its the weak thin-wall torque converter input shaft that causes issues.
A misadjusted kickdown rod will cause all sorts of problems
The TH400 with AMC bellhousing had a unique tailshaft that only worked with the Borg Warner quadratrac transfer case. You will need a different tailshaft and an adaptor, along with a transmission rebuild to install it, in order to bolt it to the New Process bolt pattern. You will likely have driveshaft issues because of the length. You will also need a different flexplate. Pretend its a Quadratac 1979 CJ7 with 258 for the flexplate.
One cool thing about the TH400 is the kickdown. Its an electronic switch. On some FSJs there was a switch similar to the one that controls your brakelights except on the gas pedal, to let it know when to downshift. On my CJ7 its a cable jobber off the throttle plate to the switch. That makes the installation more flexible.
The TH400 is exactly as strong and reliable as a TF727. A TF727 is much better than your old 998 and it uses all the old linkages, and it can be purchased for less than the cost of the fancy TH400 tailshaft adaptor. Generally installing a TH400 is a waste of time and money, but that's your decision to make.
Do a Grand Wagoneer 727 swap or go with an AX-15 and be done with it. (wish I knew for sure what needs modding to put a Jeep AW4 and NP208 in)
Okay so it's too much work. Would it be possible for me to send the 904 off to a shop as a core and ask for a 998 or 727? None of the shops will help me because of this transmission.
Quote from: carnuck on March 18, 2012, 01:38:48 PM
Do a Grand Wagoneer 727 swap or go with an AX-15 and be done with it. (wish I knew for sure what needs modding to put a Jeep AW4 and NP208 in)
This is what I've been desperately trying to do but the picking yards crush every wagon I pick from less than a week later. This is a horribly frustrating and stupid way to do business and it wastes my time and fuel.
Where are you at? (re-read. I thought it was Portland) I have a core 998 (converter snapped but it still moved until it dumped all the oil) for $50 here in Seattle. Sea-Tac trans here knows what to do with them.
Novak conversions has some interesting stuff:
http://www.novak-adapt.com/knowledge/th400.htm
If I were going to move from a 998 or 999 (Found in wranglers, a 998 can be built up to a 999) I'd go to a 700r4 or AW4 for all the drive line effort. Both are not too bad. Lots of AMC-ers going to the AW4, and lots of Jeep-ers going to the 700r4.
But a 999 build should handle just about anything short of heavy towing.
Quote from: carnuck on March 18, 2012, 01:46:30 PM
Where are you at? (re-read. I thought it was Portland) I have a core 998 (converter snapped but it still moved until it dumped all the oil) for $50 here in Seattle. Sea-Tac trans here knows what to do with them.
I saw that listing. Looks like a good idea. I'm staying out of Seattle and Bellevue for now though. My truck only gets 5MPG and I'll be in Seattle and Arlington in early April so I might be able to check it out(if I can afford it). Both of my TF904s are junk and the current issue is probably thanks to the torque converter. I would use an AW4 if I could find one. I need this car running within the next two weeks, period. I will pull out my ancient NP435 and order every adapter if need be but that's a very last resort. I don't have two weeks to spend looking for a clutch and bearings. This is my daily driver and it has to work or else I won't.
Turnaround on the 998 at Sea-Tac is 2 days
Do the AMC th400 and Chevy th400 have the same guts?
Yes. I think the TH400 is a bigger case than 727 (longer too) You could probably use '88 up Chev TH400 4x4 parts to go driver's side drop NP241 or others if they aren't too long.
I'm going to be driving an underpowered oversized piece of crap for the next few days until I can get this under control. Just curious, what were the ft/lb ratings of the TF904, TF727 and TH400?
No clue on the tf's, but the thm's names represented their torque capacities (or so it was claimed) IE: th350, 350 ftlbs, th400, 400 ftlbs (even though they will handle much more in factory form). Think of the old Buicks, Caddys, and Olds' with engines that put out close to 500+ ftlbs and weighed 4000+lbs, lol. One thing about the 400, it takes more power to turn, and it has a bit higher geared first. Your eagle will be more sluggish and fuel defficient than ever, lol, but as long as you set it up right and don't do neutral drops or any other torturous things, I'll doubt you'll ever break it.
What is a neutral drop? O_o
Puttting the car in neutral revving up the engine, and dropping it in gear, worse yet reverse drops, :o
The TF727 and TH400 are both rated at 450 ft/lbs. I suggest you read the last two posts in this thread.
http://forums.amceaglenest.com/index.php?topic=26.0
Quote from: captspillane on March 18, 2012, 01:10:06 PM
The TH400 with AMC bellhousing had a unique tailshaft that only worked with the Borg Warner quadratrac transfer case.
Not exactly. The TH-400 was used from 1965 through 1979. From 1965 through 1972 it had an adapter between the TH-400 and Dana 20 transfer case. TH-400s from 1973 through 1979 had a unique bell housing to mate to the AMC engines, earlier versions used adapters.
73 thru 79 were all BW QT but many till early '75 were still the nailhead trans with an adapter ring (my '73 and '74 were that way). Before that they were Dana 20 with a weak adapter.
The weak "texas" shaped adaptor is readily available from Scouts. A Dana 20 and a Scout Dana 300 (completely different than the Jeep Dana 300) will bolt to the back of any TH400 with that adaptor, but it will still not work unless you change the output shaft. The Borg Warner output shaft doesn't work with a Dana 20 even with the adaptor.
As far as I know every AMC bellhousing TH400 was mated to a Borg Warner case. That's exactly what I stated before. Only the pre-73 TH400, which had an adaptor ring and non-AMC bellhousing, had the Dana 20 behind it. That fact still doesn't help you bolt on your Eagle transfer case. You need an adaptor kit and tailshaft to install it in an Eagle.
I've noticed that you refer to your current transmission as a TF904. Only Iron Duke Eagles had a TF904 with Chevy bellhousing. All the automatic transmissions behind the 258 in Eagles were TF 998s.
If you are still looking to use a TH400 instead of a TF727, here is some more information.
The TF998 is 22-3/8" long.
The TF727 is 22-1/2" long.
The TH400 case is 24-3/8" long.
The Novak Adaptor is the thinnest available. Its 1.4" long, so the TH400 would come out to over 25-3/4" long.
At nearly 4 inches longer you will have driveshaft problems. You will also have clearence issues with the floor pan.
The Borg Warner 1339 transfer case used an extremly long 10 spline output shaft. The Dana 20 used a 32 spline shaft. The Dana 300 and all the New Process transfer cases used 23 spline. Advanced Adaptors only offers a 32 spline input shaft for the Dana300 and a 4-1/4" long adaptor. You must use the Novak system that has a different 23 spline output shaft with its adaptor. It costs 478 dollars.
Another reason to use the Novak adaptor is that the AMC TH400 has a bolt pattern clocked 4 degrees. You'll have to play with the different clocking positions in the Novak adaptor to make it work.
'71 to '73 nailhead TH400s with AMC adapter ring came with D20. 1/2 way through '73 QT became an option.
Quote from: captspillane on March 20, 2012, 01:13:20 PM
I've noticed that you refer to your current transmission as a TF904. Only Iron Duke Eagles had a TF904 with Chevy bellhousing. All the automatic transmissions behind the 258 in Eagles were TF 998s.
Yes that's how they were made, no that's
NOT the case with my car and that's entirely the problem with it. Yes I have a 258 motor, no I don't have a TF998 or I wouldn't be talking about this every few months. It's great in a Hornet but it's absolute crap in an Eagle. Do not want.
Quote from: captspillane on March 20, 2012, 01:13:20 PMAt nearly 4 inches longer you will have driveshaft problems. You will also have clearence issues with the floor pan.
I can manufacture my own driveshafts, that's no problem but I don't want to start cutting into the floorboard.
I've been digging around my trailer and I
do have a workable transmission for this car but I don't have the time to set it up. I need a replacement automatic that can just bolt right up in the mean time. At this point I no longer care if I have to lose my 4WD. The truck I'm driving has a bigger tank than the Eagle and half of it is being used up daily. This car is never getting fixed.
How did you come by a 4WD TF904 with AMC bellhousing? Did you splice a 2WD TF904 with a TF998 4WD adaptor?
A 2WD TF727 is pretty easy to come by. There is one for sale here in PA for $250. There is also a 2WD TF998 from a Concord for sale for $100. A 727 from a FSJ is even more common and plentiful. I can buy 5 or 6 of them from one junkyard near me for $120 each.
You can drive the car with a 2WD transmission just fine with your front driveshaft removed. You can also remove your front axle if you dissemble two old CV shafts and use the old ends to bolt your front wheel bearings together.
Good luck getting it back together.
Quote from: captspillane on March 22, 2012, 02:33:37 PM
How did you come by a 4WD TF904 with AMC bellhousing? Did you splice a 2WD TF904 with a TF998 4WD adaptor?
The previous owners were a bit more resourceful than the average mechanic. I would have to ask them about it but most of them are either dead or dying at this point and can't be disturbed. Good thing too, the sight of this transmission would probably kill them...
Quote from: captspillane on March 22, 2012, 02:33:37 PM
A 2WD TF727 is pretty easy to come by. There is one for sale here in PA for $250. There is also a 2WD TF998 from a Concord for sale for $100. A 727 from a FSJ is even more common and plentiful. I can buy 5 or 6 of them from one junkyard near me for $120 each.
I would go for it too. The issue here is the fact that I can't get to the picking yards to pull parts anymore. Portland is the sure bet for finding a TF727 whether it be 2WD or 4WD but my temporary driver isn't made for distance trips and that too is falling apart at this point. Everything in this place is crap and I can't even get a rental car. This town is a black hole.
Quote from: captspillane on March 22, 2012, 02:33:37 PM
You can drive the car with a 2WD transmission just fine with your front driveshaft removed.
Yeah that's what I was thinking. No viscous coupler, no problem. Still gotta find a new core though. I'll have time to figure this out over the weekend and I might be able to finally do something if I can leave early tomorrow.
Too bad I'm not heading down or I'd bring the 998 I have (both 2wd and 4wd in my for sale collection) The AMC pattern 904 was common on 6 cyl cars from '72 to '77.