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Post by sc397 on Jul 13, 2021 17:45:28 GMT -8
Spent more than I should to see what we can do with this thing. $500.00 for the trans and drive shaft with the yoke. The nasty looking one is a 998 out of a '72 Javelin with a 304. The cleaner one is a 42RE out of a 2WD 1996 Jeep Grand Cherokee with a 4L. Finding a two wheel drive Jeep anything in my area is a rare vehicle indeed. The basic mechanicals are not a issue. I know that it will bolt to a V8 and I know that I can figure out a cross member and drive shaft. The rest is Greek to me so I will rely on Torque Flights by Randy to figure out the rest. I also know that Randy can build a 998 to hold up to a 650HP AMC engine. My biggest concern is the electronics part of this thing. I am hoping to have it build for a street/strip vehicle (either mine or a buddy of mine). Comments? suggestions? IMG_4921 by Rick Jones, on Flickr IMG_4922 by Rick Jones, on Flickr As far as dimensionals go the bolt bell housing bolt pattern is the same. The flex plate bolt pattern to the engine is the same if I have to use it. From front back to the cross member mounting holes. 998=23", 42RE = 24 1/4". Bolt pattern is different. From front to end of output shaft. 998=31 3/4", 42RE=38 3/8"
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Post by sc397 on Jul 14, 2021 3:20:19 GMT -8
Here is one guys opinion from a Jeep web site: Jeep Grand Cherokee started using the 42RE transmission in 1993 1/2 models with the 4.0L engine. The "4" stands for 4-speed, "2" is for torque capacity, "R" is for rear-wheel drive, and "E" is for electronically controlled. This transmission is electronically controlled using a governor pressure solenoid to vary the governor pressure. The shifts are controlled by the valve body by conventional shift valves for 1-2 and 2-3 upshifts. The 3-4 upshift and 4-3 downshifts are controlled by a solenoid. Although the shifts are controlled by shift valves for the lower gears, the higher gear is electronically controlled because the governor pressure acting against it is controlled by the transmission control module (TCM). The throttle pressure is controlled by a standard cable and throttle valve. The TCM inputs for this system include engine rpm, throttle position sensor, vehicle speed sensor, transmission output speed sensor, governor pressure sensor, transmission fluid temperature sensor and overdrive "off" switch. The TCM outputs are the 3-4 shift solenoid, the governor pressure solenoid and the torque converter clutch solenoid. Here's how this system operates: As the output shaft begins to move, a 2-wire AC generator (transmission output speed sensor) begins to signal the TCM of the rpm. As the shaft speed increases, the TCM controls the governor pressure solenoid accordingly by a pulse-width modulated signal. Feedback to the TCM is provided by a governor pressure sensor to verify that the pressure actually changes. The pressure sensor is a 5-volt reference sensor. When the wheels are not rotating, voltage around 0.6 V is normal. As the wheels begin to speed up, the voltage should increase proportionately. If the voltage does increase, then the pressure is increasing as it should - this should be verified with a pressure gauge. This variance of pressure acts upon the shift valves in the valve body along with the throttle pressure to provide the shifts. As speed warrants, the TCM will apply the 3-4 overdrive solenoid, which is the only shift solenoid used on this system. The OD inputs are overdrive off switch, TPS, VSS, transmission temp sensor, output speed sensor and engine rpm. The torque converter clutch (TCC) solenoid will normally operate in overdrive, but the TCM can operate the TCC in third gear if the overdrive off switch is selected. Inputs for TCC include OD off switch, TPS, engine rpm, VSS, output speed and transmission temperature sensor. The transmission temperature sensor is mounted on the overdrive/torque converter clutch solenoid assembly and provides input to the TCM. When the temperature sensor reports 30 degrees F or colder, there will be no overdrive, and below 50 degrees F, there will be no torque converter clutch. If the transmission fluid temperature sensor reports an overheating condition (over 260 degrees F) and the transmission is currently in overdrive, the TCM will downshift to third gear. The TCM will also light the LED in the dash-mounted OD off switch until the temperature drops below 230 degrees F. However, the torque converter clutch may still be operational. This system has self-diagnostics. Fault codes can be read with a scan tool or by cycling the ignition key three times, then counting the flashes of the LED in the OD off switch. The diagnostic connector is located inside the vehicle to the left of the center console. The default mode of the TCM is third gear. Manual shifting of reverse and second gear is possible when in default mode. Default mode happens after a fault code is set.
From Wikipedia: A500 (40RH/42RH/40RE/42RE/44RE) The A500, later renamed 40RH and 42RH (hydraulic controlled governor pressure) and 40RE, 42RE, 44RE (electronic controlled governor pressure, 1993-up), was an A904 derivative used in trucks and vans. Introduced in the 1988 model year on a limited basis, it was the first light-duty Chrysler four-speed automatic and was placed behind the 3.9 L and 5.2 L engines for light-duty purposes. Forward direct clutch drum (same as the A998) usually has a 4 friction disc pack - an A999 forward direct clutch drum with the 5 friction disc pack does interchange. A bolt in low/reverse overrun clutch assembly (shared with the A904 derivatives manufactured after 1988) uses a roller clutch which is shared with the GM THM200 and THM2004R. Much like the later production A904 with a wide ratio gear a double wrap low-reverse band is used. An extension housing mounted (New Process built) overdrive unit was bolted to the rear of the case to provide a total of four forward speeds; the extension housing and its internals interchange with the 46-48RH/RE (A518/618) - when overhauling the overdrive unit transmission rebuilders usually would use replacement parts from the A518/618 overdrive section since the A500 internals are light duty e.g. number of friction discs and thick pressure plates. The overdrive housing (RWD/2WD) uses an output shaft yoke commonly shared with the A727 and its later derivatives except the A618/48RE. Electronic governor pressure was phased in during the middle of the 1993 model year where it was renamed as the A500SE - Jeep Grand Cherokees equipped with the 4.0L used the A500SE/42RE since the middle of the 1993 model year replacing the AW4. Oil pans used with the A500SE/42RE is similar in design to the one used in the A500 with a clearanced area for the shift solenoid. The pan and filter were updated during the 1998 model year with some Dodge applications which has a deeper oil pan and a redesigned oil filter which is held with 2 valvebody screws (the single oil port filter does interchange with the older A500 and A904 derivatives along with the oil pan). This transmission was replaced by the 42RLE in 2004.
Gear ratios:
1 2 3 4 R 2.74 1.54 1.00 0.69 2.21 Applications:
1989-2001 Dodge Ram pickup 150/1500 V6/V8(2WD) 1989-2003 Dodge Ram Van B150/B250 V6/V8 1989-2003 Dodge Dakota 1993-2004 Jeep Grand Cherokee I6 1996-1998 Jeep Grand Cherokee 5.2 V8 1999-2003 Jeep Grand Cherokee 3.1 TD 1998-2000 Dodge Durango 5.2L V8 (4WD (98-99) or 2WD (99-00)) 1998-2000 Aston Martin Virage V8 5.3
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Post by landbarge on Jul 14, 2021 3:28:32 GMT -8
The last one of those I saw that was started and never finished involved the guts from a Dodge Dakota RH version out of a V6.
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Post by javtwotone on Jul 14, 2021 4:20:19 GMT -8
You say this is one guys opinion? where's the opinion? that's just operation info.. I'm sure I'm oversimplifying this, but couldn't you control the solenoids with switches, or maybe a VSS and relays? If it is for a street/strip car, you certainly don't need full automatic function. Maybe could by-pass some of that crap and still get the TCM to work..
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Post by 69Rebel on Jul 14, 2021 6:06:51 GMT -8
There are aftermarket transmission controllers out there, but they're a little spendy.
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Post by spud on Jul 14, 2021 6:16:44 GMT -8
Pretty sure i can be done, a 42 rh might be a better start since it aint electronic. You may be able to find a 42rh valvebody seperate. If you go with electroic servo valvebody, i figure you could creat your own controls like you did on the aisin warner. Also take care of your unused 998 parts because i want to buy them. I dont see why you are crossbreeding the 42re? Its gonna have way better stuff than the 998? About the only advantage you might gain (if the 42 re doesnt already have them, which i simply am not sure of) may be the heavier low band and servo in the 998. The 42 re has stronger everything else, and a lower first and second ratio. I think just using the 42re as is would work. The myth about “ beefing” up this series of trans is kind of a relative thing. Its basically about putting the most clutch plates, widest bands an such in, the 42 re has heavier everything already. Not sure about the rear servo and low band, it may be the same as the 998/999. If so, there are no advantageous parts in the older trans. The one part which might have a perk is the case, but it would need modded in oil passages for 42re guts. So my point is… your scuttling a 42 re for what from the 998? Its a superior trans in just about every internal i know of? If your concerned about the 42 re, the one thing which might give you trouble is the od section, but only when it has too few clutches. There are heavier parts for that, if it dont already have them. For more info go to ken parkman. Theres a quick chat about this i think in my 304 javelin topic. Parkman can hook you up with his convertor guy, so you can get a higher stall lockup convertor, which is about the only thing i can think of that you may need to make that 42 re with the exception of an electronic control, and he might recommend a resource for that
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Post by sc397 on Jul 14, 2021 6:44:06 GMT -8
As near as I can find out they didn't use the 42RH behind the 4L Jeep engine. If I wanted to function like a normal automatic I would just use a AW4 again. For this one I want it to be fully manual shift with a switch for the overdrive if that is possible. Basically a race transmission with overdrive. It is sort of intended for our buddy Russ who drives his 360 Hornet to and from the strip to drag race it. I personally don't think that it is a better transmission than the AW4 but I think it is cheaper to hop up than the AW4. We will soon find out. I have a line on a couple more 998's if you want me to ship one to you Spud. I can prolly get them for $100.00 each. This chart sort of tells the story although the years are a bit confusing. I think it has to do with weather it is a Wrangler or Grand Cherokee I guess. Screenshot_2020-04-20 List of AMC Transmission Applications - Wikipedia(1) by Rick Jones, on Flickr The Jeep 42RE automatic transmission is a descendant of Chrysler's Torqueflite 727 transmission and directly related to the A500 light-to-medium-duty Chrysler truck transmissions. The 42RE was first used in Jeep Cherokee vehicles in late 1993, until it was replaced by the 42RLE in 2004. It is a four speed, automatic overdrive, electronically controlled transmission, which differs from the 42RH transmission because of the hydraulic control. You can identify the transmission with visual clues and by locating the model/part numbers and the date code. I kinda found this out when researching flex plates. I have a flex plate from a 1993 4L Jeep and it will not bolt on to this 1996 torque converter. So I went on line and found out what I could. I found that the P art numbers for the 1993 through 1996 flex plate is 53006328 and the part number for the 1996 through 2004 is 52118551. Nice that 1996 is a overlap year. CHRYSLER PART #53006328 FLEXPLATE FOR 1991-96 WRANGLER AND CHEROKEES WITH 4.0L ENGINES AND 1993-96 GRAND CHEROKEES WITH 4.0L ENGINES. I did fine one listing that cryco part #52118551 is for the 1997 through 2004 Jeep with the 4L. If I use the 4L flex plate I can have it match balanced to an existing 7727/904 flex plate and we would have to use the 4L starter which might be a good thing. I could probably just re-drill holes in the existing 727/904 flex plate to make it work as well. I will have to measure the fore-aft height between the two.
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Post by sc397 on Jul 14, 2021 7:50:12 GMT -8
You say this is one guys opinion? where's the opinion? that's just operation info.. I'm sure I'm oversimplifying this, but couldn't you control the solenoids with switches, or maybe a VSS and relays? If it is for a street/strip car, you certainly don't need full automatic function. Maybe could by-pass some of that crap and still get the TCM to work.. I deleted the heading that stated: "One of the worst transmissions ever made" And I think that you are right about the solenoids and switches.
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Post by ramblingrebel on Jul 14, 2021 8:19:28 GMT -8
i think mr parkman has this set up in his bricklin, i was letting him work the bugs out and then follow in his tracks.....well that WAS my plan...honest
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Post by spud on Jul 14, 2021 8:55:04 GMT -8
He has a similar concept. He retained the lockup convertor feature. You have started a holy grail topic here mr rick. Gonna get a lot of attention! I think you might get aquainted with cope and A&A, they are great resources for info and torqueflite tech and parts.
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Post by ramblingrebel on Jul 14, 2021 9:30:37 GMT -8
right, i remember him explaining the lock up convertor feature he figured out, still something i'd like to go down one day, with rebel and j10....eventually....
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Post by sc397 on Jul 15, 2021 6:31:21 GMT -8
According to Russ who has spoke with John Donoto we need a 3-prong wire connection otherwise we need a computer. John is a AMC guy and trans engineer who worked for cryco on transmissions during the '80's and '90's. Don't know where the 3-prong connection goes to or from but I guess we will find that out. Hopefully we can just use a reverse manual valve body put in and shift the whole thing manually. I will try to get it to Torqueflights by Randy in the next couple of weeks. I will be real curious on what he comes up with for a Torque Converter.
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Post by landbarge on Jul 15, 2021 7:14:00 GMT -8
3 prong. I'd say ground, converter LU and OD
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Post by spud on Jul 16, 2021 8:18:24 GMT -8
The 42 re has the wide ratios, which could be good for track performance, depends on engine tune, but its a small difference. It works good for dual porpose. Especially with a broad powerband. Not good for a peaky tune. They were worth a tenth in my car, cut down on tirespin and 60 ft. They helped me with the 3.15s and 27 inch tires. 42re also has improved hydraulics, much greater volume lube circuits, there are several differences in the hyd circuits, it uses an electronic governor, so i dunno how the manual vb will sort out, thats one fuzzy area i can think of, since the 42re has several differences in the vb and oil circuits. I’m speaking with thoughts, not know facts. Personally i would be inclined to retain the stock vb, and either shift it manually or let it shift itself, but i’m just interested in consistancy.
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Post by stickshifter on Jul 16, 2021 8:37:25 GMT -8
I was doing a bit of research on this topic for my Mat Wagon. As stated, the RH is what you need. That is the one with the 3 prongs. I was looking at the 46rh/518 since that is basically a 727 with overdrive. The 42RH just isn't the ideal trans for a bigger inch engine that will also do some towing. But you really need an aftermarket controller to make it work properly. Yes, you can do it with switches but that is not a great way to drive a car. The 46RH has a Mopar style bell housing on it too. To get past that I was going to use the bolt on bell housing from a (I think) BW trans by cutting off the BH of the 46RH and adapting the other one. Or, use a Ultrabell that bolts directly to the front pump. This can still be an issue as the 46RH is longer than the 727 and surgery must be preformed on the floor.
My current plan is to use an Ford AOD with an adapter mid plate. I have one and it is smaller than the 46RH and the upgrade kits are everywhere. It is completely mechanical/hydraulic so no need for outside controllers. No lock up converter but I don't think that is much to give up. I have heard the trick is to get the gear set out of an EAOD as they are stronger. It is a cheap way to go with a lot of parts available.
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