77 J10 transfer case

[AJW137]

Hello,

I have a 1977 J10 that needs a transfer case. It's the borg Werner quadratrec the numbers on it were 13-06-065-901. I was wondering for those of you who know what they are doing. What does it take to swap to a twin stick Dana 20 on the j10?

[tgreese]

The Borg-Warner Quadratrac uses a unique output shaft in the transmission. The output shaft is the last part to come out of the case when you completely disassemble the transmission. You can purchase a conversion kit, but you will need to install the new transmission output shaft. There is no easy swap out there, Dana 20 or otherwise.

The Quadratrac also uses an offset rear axle that matches the offset rear output of the transfer case. There are conflicting reports about whether you need to change to a centered axle or not. (Sorry, disregard previous sentence. Not an issue for a pickup which uses a longer driveshaft).

Most owners decide that it's best to deal with the existing Quadratrac and service or repair than to swap. What issues do you have with the existing transfer case?

First post! Welcome from Boston.

[AJW137]

The Borg-Warner Quadratrac uses a unique output shaft in the transmission. The output shaft is the last part to come out of the case when you completely disassemble the transmission. You can purchase a conversion kit, but you will need to install the new transmission output shaft. There is no easy swap out there, Dana 20 or otherwise.

The Quadratrac also uses an offset rear axle that matches the offset rear output of the transfer case. There are conflicting reports about whether you need to change to a centered axle or not. (Sorry, disregard previous sentence. Not an issue for a pickup which uses a longer driveshaft).

Most owners decide that it's best to deal with the existing Quadratrac and service or repair than to swap. What issues do you have with the existing transfer case?

First post! Welcome from Boston.

I started the truck and put it in drive and the car wouldn't move. I gave it gas and it wouldn't move. I drained the transfer case and it was a dark color and the plug had metal shavings all over it. The drain pan also had metal shavings in it. I'm in high school and I'm new to all of this. How much is a good quadratrac transfer case? I've heard of people doing something to make the chain in it last longer if you know what that is let me know.

Thanks for the help!

[letank]

Welcome from SF, bay area.

Dark color is/was the standard of the quadratrac (QT) it stinks also. How many miles, by now it may have been swapped to a part time kit, you will have locking hub on the front axel.

Otherwise not moving could be the vacuum control of the transmission. On the right side of the trans there is a vacuum modulator that is connected to the intake manifold vacuum. IIRC a quick test is to plug the vacuum tube or rubber line -to prevent a massive vacuum leak- at the source, at the engine side. Now your truck should move. Vacuum modulator go bad, and can be replaced.

Otherwise all QT knowledge is here:
https://jubileejeeps.org/quadratrac/

[Stuka]

To swap in a Dana 20 you need the adapter that goes on the back of the TH400 for it. I believe Novak sells one. You also have to replace the output shaft on the transmission. Which does require pulling the trans, removing its internals, and putting the output shaft in for the D20.

If I was going to go through all that work, I would look into putting an NP style t-case in. Though I am unsure as to adapters for the TH400 for that. Though the TF727 that came in 80+ FSJs are setup that way from the start.

[AJW137]

Welcome from SF, bay area.

Dark color is/was the standard of the quadratrac (QT) it stinks also. How many miles, by now it may have been swapped to a part time kit, you will have locking hub on the front axel.

Otherwise not moving could be the vacuum control of the transmission. On the right side of the trans there is a vacuum modulator that is connected to the intake manifold vacuum. IIRC a quick test is to plug the vacuum tube or rubber line -to prevent a massive vacuum leak- at the source, at the engine side. Now your truck should move. Vacuum modulator go bad, and can be replaced.

Otherwise all QT knowledge is here:
https://jubileejeeps.org/quadratrac/

Ok gotcha. But what about the metal shavings found in the fluid. My auto shop teacher seems to think it is metal shavings from warn out gears.

[tgreese]

Not a good guess. Chain driven, no gears. Two big sprockets and a link belt between them. Read here.

https://jubileejeeps.org/quadratrac/index.htm

The chain wears out, but it slips and bangs when worn. Metal chips could come from the splines in the differential, or?

There is a vacuum shifter for "emergency drive" but I believe it only changes from normal full-time to locked part-time. Low range is a separate planetary transmission bolted to the back of the transfer case - see the article I linked above. It has a low-neutral-high shifter, which should be a flag shifter on the floor/tunnel, IIRC. If in neutral, the Jeep will not move.

Do you have locking hubs? If so, keep them locked in for now.

There is the complete 1977 TSM here, free to read and download. Suggest you do some reading and familiarize yourself with your Jeep. https://oljeep.com/edge_parts_man.html

[tgreese]

To swap in a Dana 20 you need the adapter that goes on the back of the TH400 for it. I believe Novak sells one. You also have to replace the output shaft on the transmission. Which does require pulling the trans, removing its internals, and putting the output shaft in for the D20.

If I was going to go through all that work, I would look into putting an NP style t-case in. Though I am unsure as to adapters for the TH400 for that. Though the TF727 that came in 80+ FSJs are setup that way from the start.

Novak has an adapter for TH400 to the Dana 300 that they say works with other NP transfer cases. Presume you're thinking something like the NP241C? Are there other passenger drop options?

[Stuka]

To swap in a Dana 20 you need the adapter that goes on the back of the TH400 for it. I believe Novak sells one. You also have to replace the output shaft on the transmission. Which does require pulling the trans, removing its internals, and putting the output shaft in for the D20.

If I was going to go through all that work, I would look into putting an NP style t-case in. Though I am unsure as to adapters for the TH400 for that. Though the TF727 that came in 80+ FSJs are setup that way from the start.

Novak has an adapter for TH400 to the Dana 300 that they say works with other NP transfer cases. Presume you're thinking something like the NP241C? Are there other passenger drop options?

The 208 and 241 are what came to mind. Both are stronger than the D20, though cannot be twin sticked easily. The D300 can.

[rocklaurence]

IMO, the TF727 with a Passenger drop NP case is the cheapest option. I do know that a D300 will bolt to a TF727 but the front drive shaft wont clear the Trans pan unless the case is clocked down and the D300 is short. So, clocking it moves the drive shaft towards and under the transmission. An NP from a Chevy or Dodge would work better but Im nor sure if the inputs can be swapped between the different OEMs. For example: Would a Jeep 208 input swap into a Dodge NP208?

[AJW137]

Not a good guess. Chain driven, no gears. Two big sprockets and a link belt between them. Read here.

https://jubileejeeps.org/quadratrac/index.htm

The chain wears out, but it slips and bangs when worn. Metal chips could come from the splines in the differential, or?

There is a vacuum shifter for "emergency drive" but I believe it only changes from normal full-time to locked part-time. Low range is a separate planetary transmission bolted to the back of the transfer case - see the article I linked above. It has a low-neutral-high shifter, which should be a flag shifter on the floor/tunnel, IIRC. If in neutral, the Jeep will not move.

Do you have locking hubs? If so, keep them locked in for now.

There is the complete 1977 TSM here, free to read and download. Suggest you do some reading and familiarize yourself with your Jeep. https://oljeep.com/edge_parts_man.html

The low neutral high shifter was not in neutral. Do you recommend checking inside the transfer case? Or the vacuum shifter?

[tgreese]

I have been around these transfer cases for many years, but I have not owned or done any major work on one. I believe the vacuum shifter won't affect whether the transmission moves or not, only whether it's in full-time or part time mode. Hopefully someone here with hands-on experience will confirm.

Other obvious things - this is a full-time transfer case and both axles must be on the ground and connected for it to move. There is a limited slip differential between the front and rear axles that will slip if one of the axles is broken/disconnected. This is the purpose of the vacuum switch - to lock/unlock the differential and allow the front and rear driveshafts to be connected rigidly aka "emergency drive."

Both driveshafts are in place? No broken gears or broken axle shafts in the axles? No locking hubs that are disengaged? Your shop teacher can help with this. Test that the axles are ok.

You can remove the back half of the transfer case with the unit in the car. If I tested everything else and the truck still did not move, that seems like the right next step.

Have you downloaded the 1977 TSM from the link I gave above? These factory manuals usually have diagnostic charts that may help you to isolate the problem. Jeep offered this transfer case through 1979, and the '79 TSM seems more detailed than the one for '77. Look at the '79 TSM page 2D-17 for "Service Diagnosis." Suggest you print out this section and go over it with your teacher, then decide what to do next.

[Stuka]

Just an FYI,

I saw you had two of these threads going at the same time, with different people responding, so I have merged them together. So its worth going back through the responses as there are some you have likely not seen.

[letank]

found this old post:
viewtopic.php?t=11771

and the quick and dirty check by Tat:

1) There are times when the automatics seem to lose their minds and refuse to do anything. My TH400 Chief did the same thing about a week ago after sitting for a month or so. It's parked on a slope with the nose downhill and I started her up in neutral and let her roll into the street, and when I put the shifter into Drive...nothing...

After a minute of idling everything worked as usual.
I suspect that the pump lost it's prime.

2) Normally, a defective modulator will make itself known by raising the shift points but not prevent the vehicle from moving.
If you can feel the bump from the detents as you move the selector through the gear positions your problem is likely a T-Case in neutral, oil pump inoperative or unable to prime or possibly the internal shift valve or linkage is broken/loose.
One way to confirm the oil pump is functioning is to pull the drivers side cooling line, place the end into a 3-5 gallon bucket and run the engine for 15-30 seconds. Oil should begin coming out almost immediately. 15-20 seconds should push out a quart of ATF or so at an idle.

No substantial oil flow would mean the pump is not working.

and another

viewtopic.php?t=10711

[seventynine]

Does it have a low range unit on it? If so there will be a lever on the hump near the right side of the driver’s seat. There are three positions for that lever - Hi-Range - Neutral - Lo-Range - if it’s in Neutral (middle position I think) it won’t move.

[AJW137]

Thanks for your help everyone. I took the transfer case off and found a bunch of rubber sealant inside the transfer case that had gotten caught up. Everything is in good condition. New issue is, I'm in highschool and stuff in the shop gets moved around a lot and my bolts got taken. I'm missing at least one from every section. Can anybody tell me the sizing of the bolts so I can buy them at Home Depot or at a hardware store?

[rocklaurence]

Thanks for your help everyone. I took the transfer case off and found a bunch of rubber sealant inside the transfer case that had gotten caught up. Everything is in good condition. New issue is, I'm in highschool and stuff in the shop gets moved around a lot and my bolts got taken. I'm missing at least one from every section. Can anybody tell me the sizing of the bolts so I can buy them at Home Depot or at a hardware store?

You can use a selection of taps to figure out what fasteners you need