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***Didn't know if this should go here or in the Off-Road forum. Please move if I was wrong.***
Need some advice from all of you veterans here.
I have a 85 4x4 Pickup that has a Chevy 4.3 V6, mated to a Chevy 700r4 Tranny, mated to an adapter, mated to a 23-spline Toyota Transfer Case with TrailGear 4.7 Kit.
I just got everything running decently and started driving it around the block.
However, there is a problem. When I am going about 35 mph and lift off the gas completely and just coast, the drivetrain rattles really badly. Under load, everything sounds fine.
I took it to a tranny shop and they said they think it is coming from the transfer case. The tranny was a fresh rebuild, so I am also thinking it is the transfer case. I also don't think it is the adapter since that seems like a pretty simple piece.
What would you guys do?:
- have the t-case rebuilt at a general tranny shop (I don't think we have any specialized Toyota 4x4 places here in Albuquerque, NM). The quote seemed pretty expensive. $800 just to look at it. Maybe that is the going rate.
- try to rebuild myself. I have never done one and don't know anyone here that could help me. Seems daunting especially with the 4.7 gear kit in it.
- order a "new" one from TrailGear: https://trail-gear.com/drivetrain/tr...fer-cases.html
What would be the most cost effective and least amount of headache?
I was excited to have it running and would like to get it back there quickly.
You are kindof going down a direction based on a lot of assumptions. The shop said they think it is coming from the transfer case, but how did they diagnose that? By driving it and listening?
First step is to figure out where it is coming from. Can you remove the rear driveshaft and drive it in 4WD high using front wheels and see if noise still happens.
Ya... you are correct, I do have a lot of assumptions.
The shop did drive the truck, put it in every configuration and told me they think it was the transfer case and quoted $800 just to pull it an look at it closer.
Well, my advice was going to be to try and narrow it down, but if you already have the case out, then it's going to hard to figure out where the noise was coming from. You can certainly open up the case and look around, maybe you'll find the problem. I guess I was thinking more along the lines of it could be other things, like driveshaft, rear diff, loose ubolts on your rear springs...maybe a million other things. For my personal taste, it would stink to open up the tcase, not find any obvious problem, and put it back together all to have not solved the issue with the noise.
I can pretty much assure you that the noise was coming from the transfer case area. All the springs bolts, driveshaft bolts, etc are all tight. When it would happen you could "feel the noise" from on top of the case (open to the cab at the moment). Thats not a smoking gun but it is definitely something
Also a shop looking at it and "feeling the noise" even furthers my theory. Yes, it could be something else, but I would really be surprised.
If you were at the state (t-case already removed), and no experience with rebuilding t-cases, what would you do?
- Learn to rebuild t-cases (can you buy individual parts if I find out what part is the culprit?)
- Buy one and call it good (this would either fix the problem or definitely confirm it wasn't the t-case)
Download the TG in instructions and rip the t case apart. They are super simple. Just lay out the parts as the come out to make re assembly easier.
If its grinding, you should be able to see form where.
Was a bought 4.7 case or did someone install the gears? maybe they didn't clearance the case enough for the 4.7 gears.
Edit: went through your pics. Looks like youve had it apart before?
Sorry. I replied this morning but I guess it didn't go through. An old buddy built it. I just snapped the picture to have for the archive. I don't have any expierience whith t-cases.
I have read throught the instructions though, seems do-able, however, seems like a lot of guess work on my part to figure out what needs to be fixed. I am at a crossroads.
I will assume the truck is lifted. Are you running a cv rear drive shaft with the pinion angle set correctly (2* under the slope of the shaft)? A nasty rattle/grinding noise from the t case on decel is a common issue people run into when lifting these trucks and running a non cv shaft.
I will assume the truck is lifted. Are you running a cv rear drive shaft with the pinion angle set correctly (2* under the slope of the shaft)? A nasty rattle/grinding noise from the t case on decel is a common issue people run into when lifting these trucks and running a non cv shaft.
Truck is indeed lifted. What do you mean by a cv shaft? I am not familiar with this term. Are you meaning the rear drive shaft?
I also didn't have a front drive shaft installed. Could that have been the problem?
Truck is indeed lifted. What do you mean by a cv shaft? I am not familiar with this term. Are you meaning the rear drive shaft?
I also didn't have a front drive shaft installed. Could that have been the problem?
yes, refering to the rear shaft. On a stock 85 the front shaft has a cv joint at the t case, the rear shaft does not. When you lift the truck you want to add a cv to the rear shaft and set the pinion angle 2* under the slope of the shaft. If this hasnt been done I I'm pretty confident it is the cause of your issue.
Last edited by toyoda addict; 09-29-2020 at 09:03 AM.
Front shaft has nothing to do with it, what he is saying is that you have lifted your truck, which increases the angle of the rear driveshaft from output of tcase to the rear differential. This increased angle can be compensated for by shims to aim the pinion more upward toward the tcase. Instead of that, a CV jointed shaft (like your front drive shaft) can be used in the rear.
By the way, you have a non factory transmission with an adapter, so is your new drivetrain any longer or shorter than the original? If it is longer, then that again adds to the angle on the driveshaft because now it has to cover a longer vertical distance over a shorter horizontal distance, which means higher slope.
I don't know if the driveshaft is your problem or not, and that's kindof why I was going to suggest that you do some more investigation before you drop the case and start taking things apart. I realize you are anxious to get it fixed, but if you jump the gun on everything you are going to waste time, money, and effort on your part.
Is your new drivetrain any longer or shorter than original? Was the driveshaft shortened or lengthened to make it work? Can you measure your pinion angle? How much lift did you add?
Front shaft has nothing to do with it, what he is saying is that you have lifted your truck, which increases the angle of the rear driveshaft from output of tcase to the rear differential. This increased angle can be compensated for by shims to aim the pinion more upward toward the tcase. Instead of that, a CV jointed shaft (like your front drive shaft) can be used in the rear.
By the way, you have a non factory transmission with an adapter, so is your new drivetrain any longer or shorter than the original? If it is longer, then that again adds to the angle on the driveshaft because now it has to cover a longer vertical distance over a shorter horizontal distance, which means higher slope.
I don't know if the driveshaft is your problem or not, and that's kindof why I was going to suggest that you do some more investigation before you drop the case and start taking things apart. I realize you are anxious to get it fixed, but if you jump the gun on everything you are going to waste time, money, and effort on your part.
Is your new drivetrain any longer or shorter than original? Was the driveshaft shortened or lengthened to make it work? Can you measure your pinion angle? How much lift did you add?
I really appreciate all your guys help. I think I am going to put the t-case back in and look at all of this stuff.
The truck has a 6" TrailGear lift on it.
The tcase is mounted to the same brace that bolts the frame, so I don't think the tcase moved from the stock position.
I am unsure about any rear drive shaft modification, ill have to measure the angle and length.
I guess my ignorant thought is that i didn't make any noise when accelerating or braking, only when coasting.
Got any links to modified driveshafts (both front and back) that are "cv style"?
Last edited by subaruwrx88011; 09-29-2020 at 09:14 AM.
I really appreciate all your guys help. I think I am going to put the t-case back in and look at all of this stuff.
The truck has a 6" TrailGear lift on it.
The tcase is mounted to the same brace that bolts the frame, so I don't think the tcase moved from the stock position.
I am unsure about any rear drive shaft modification, ill have to measure the angle and length.
I guess my ignorant thought is that i didn't make any noise when accelerating or braking, only when coasting.
Got any links to modified driveshafts (both front and back) that are "cv style"?
Thanks for all your help guys. With all of your guidance I started to do my research and I am pretty ticked off.
10 years ago I paid a buddy to install the Trail Gear lift kit. I told him that I wanted the 3" kit. He ordered the 5", and installed (including welding) without telling me. I was ticked off at the time as well but what was done, was done.
I have had the truck in my garage and have been working on it very slowly ever since. My buddy has been long gone. I finally got the truck running and then this problem came up.
With your guy's help I have done a lot more digging.
Based on the Trail Gear 5" Front and Back Classic Lift Instructions:
1. The back axle wasn't angled up towards the tcase like it should have been. I now I have to cut the perches off and redo those steps.
- It does indeed need a custom drive shaft with a double cardan.
2. The front actually needs a high pinion 3rd member mated to a dual t-case for it to work properly.
In addition, I still don't know if the single case needs to be rebuilt or replaced.
I am at a crossroads, it was always my dream to have this running well enough to actually enjoy it, however, with it now needing thousands of dollars in additional parts I am thinking about seller her.
Just had my fist kid, so money and time is tight.
Thanks for all your help guys. With all of your guidance I started to do my research and I am pretty ticked off.
10 years ago I paid a buddy to install the Trail Gear lift kit. I told him that I wanted the 3" kit. He ordered the 5", and installed (including welding) without telling me. I was ticked off at the time as well but what was done, was done.
I have had the truck in my garage and have been working on it very slowly ever since. My buddy has been long gone. I finally got the truck running and then this problem came up.
With your guy's help I have done a lot more digging.
Based on the Trail Gear 5" Front and Back Classic Lift Instructions:
1. The back axle wasn't angled up towards the tcase like it should have been. I now I have to cut the perches off and redo those steps.
- It does indeed need a custom drive shaft with a double cardan.
2. The front actually needs a high pinion 3rd member mated to a dual t-case for it to work properly.
In addition, I still don't know if the single case needs to be rebuilt or replaced.
I am at a crossroads, it was always my dream to have this running well enough to actually enjoy it, however, with it now needing thousands of dollars in additional parts I am thinking about seller her.
Just had my fist kid, so money and time is tight.
I wouldn't be happy about a tall spring like the tg 5'' either. That said, as far as being usable, I would think dual cases would take care of any front driveline issues. Sounds like a good excuse to get a dual case setup. I cant imagine not having dual cases in a trail Toy.
I doubt there is anything wrong with the tcase, they are pretty tuff. The drive train noise you describe is pretty much guaranteed with 5'' springs and no cv.
Ok! after a couple of days of being sad at the thought of selling my baby, I am seriously considering doing a dual case. I was hoping to lean on you guys for guidance on what I need to buy.
Here is the current setup: 4.3 Chevy V6 TBI -> Chevy 700r4 tranny -> 23 spline adapter -> 23 spline gear driven tcase (4.7 Trail Gear kit which I think made it a 23 spline if I remember correctly)
Here is the list I think I need, please let me know what is missing:
1. another tcase (do I need a 23 spline or will the adapter convert a 21 into a 23 spline?)
2. dual case adapter (same question as above)
3. dual case brace (currently the tcase is mounted to the stock brace) - does this need any welding work or is it bolt on?
4. Custom double cardan drivelines (need to measure after cases are in) - any parts I need to buy to make this happen? do I get a local shop to make them for me?
Am I on the right track? Anything I am missing?
anyway to make the tcase shifter be next to each other?
Ok! after a couple of days of being sad at the thought of selling my baby, I am seriously considering doing a dual case. I was hoping to lean on you guys for guidance on what I need to buy.
Here is the current setup: 4.3 Chevy V6 TBI -> Chevy 700r4 tranny -> 23 spline adapter -> 23 spline gear driven tcase (4.7 Trail Gear kit which I think made it a 23 spline if I remember correctly)
Here is the list I think I need, please let me know what is missing:
1. another tcase (do I need a 23 spline or will the adapter convert a 21 into a 23 spline?)
2. dual case adapter (same question as above)
3. dual case brace (currently the tcase is mounted to the stock brace) - does this need any welding work or is it bolt on?
4. Custom double cardan drivelines (need to measure after cases are in) - any parts I need to buy to make this happen? do I get a local shop to make them for me?
Am I on the right track? Anything I am missing?
anyway to make the tcase shifter be next to each other?
Get a 21 spline RF1A case, for the crawl box portion. Then you will need to swap the 21 spline input to 23 spline. This will be easy to do while you are installing the dual case adapter to the crawl box. You could try and find a 23 spline turbo case but good luck and it would be expensive if you found one.
23 spline dual case adapter.
The above is accurate to the best of my knowledge based on the setup you describe.
Dual case crossmember. BudBuilt, Front Range, TG, etc. Whatever works best for you.
Get an 84-95 front shaft for the CV. 86-95 will need the CV clearanced. Have it re tubed to the length you need. I always send mine to https://www.highangledriveline.com/. They do good work, are familiar with Toyota stuff and know how to clearance the CV. Don't forget to have the CV clearanced. You may neede a triple drilled tcase flange to match the bolt pattern on the CV.
Bro is just trying to justify buying a fancy new dual case hahah. We're all guilty i suppose. Just shim your rear axle 2 or 3 degrees up and get a one-piece driveshaft that fits. Then take the thing wheeling and see how often you actually need to crawl as slow as dual cases would allow. I have been running a single t-case with 4.7s for a while and got through all kinds of hairy ˟˟˟˟. I wouldn't waste thousands more in fancy parts unless you really need to be creeping crawling constantly. Just my 2cents
Last edited by Lono&theGremlin; 10-06-2020 at 09:57 PM.
Bro is just trying to justify buying a fancy new dual case hahah. We're all guilty i suppose. Just shim your rear axle 2 or 3 degrees up and get a one-piece driveshaft that fits. Then take the thing wheeling and see how often you actually need to crawl as slow as dual cases would allow. I have been running a single t-case with 4.7s for a while and got through all kinds of hairy ˟˟˟˟. I wouldn't waste thousands more in fancy parts unless you really need to be creeping crawling constantly. Just my 2cents
I appreciate this perspective. Thanks.
Thoughts on the original problem with the extreme rattling?
Is this something you are living with? Did the shims fix it for you?
09-27-2020, 04:38 PM
