Transmission Problems

[CivilEGR]

I took the M1008 out for the first time in a few months and noticed a decent puddle under the transmission. Actually, it was under the skid plate under the transfer case, but I think that's just where it was collecting. I put a pint of fluid in and drove it out the garage and things were OK. Then I put it in reverse and it surged a few times but did move in reverse. I checked the transmission fluid again and it was rather foamy, and low, so I added another pint. I put it in D and went down the road and it shifted fine, but I tried reverse again and I got nothing. I also noticed that the shift indicator seems like it's 1 off. When I put it in D, it shifted twice, but I didn't get it fast enough to shift to third. Then I put it in N and it would still go forward. In R it didn't go anywhere. Anyone have any thoughts on where to start trouble shooting?

 

[NDT]

I would start by verifying if the PRND21 detents inside the transmission are lining up with the steering column indicator.

 

[Skinny]

The indicator needle isn't directly tied to the linkage. It's just clipped onto the column. Pull the shifter down and feel what gear you are in instead of looking at the cluster.

Reverse is usually the first to go when fluid is low. It needs the highest pressure to work. Get you fluid sorted out and the shifter before jumping to any conclusions.

 

[CivilEGR]

The indicator needle isn't directly tied to the linkage. It's just clipped onto the column. Pull the shifter down and feel what gear you are in instead of looking at the cluster.

Reverse is usually the first to go when fluid is low. It needs the highest pressure to work. Get you fluid sorted out and the shifter before jumping to any conclusions.

The reverse/fluid issue makes sense. If too much of my fluid leaked out, when I tried reverse the first time and felt it surging, that was probably the reverse slipping in an out. And the bubbles I saw on the stick were likely because it was stirring too much air in the system. However, this does mean I need to nail down the leak and get it fixed.

The linkage to indicator is a separate issue, but I think it's in the linkage. I vaguely recalling driving over some shrubs the last time I was out and could have gotten something wedged in there.

 

[cucvrus]

This is a reverse band similar to the TH400. If it is bad and worn it will have no reverse. I have been thru many reverse bands over the years with plow trucks. No amount of magic oil or changing filters is going to fix the issue. I have seen it happen in a heartbeat and I seen it progress with a hesitation to go to reverse. Hesitation and slow response means the internal seals and valves need overhauled internally. My terms may not be correct but I spend a lot of money over the years getting transmissions overhauled. Once again a band-aid repair for a few hundred dollars will be just that. The cooler and cooler lines need to be reverse flushed and the job done right. Unless you like replacing transmissions regularly. And my advise is do NOT buy a used 30 year old transmission and install it because someone told you it shifted nice and worked great. But again not my truck. Do as you wish. All good things come to and end and need a bit of rebuilding and parts replacement by a competent, reliable shop that warrants what they do. Take Care and Good Luck. No Sugar Coating.

 

[Skinny]

I wouldn't rebuild a transmission until the fluid level and condition are sorted first. You need a pressure gauge to diag a no reverse condition before jumping to conclusions.

Cucvrus is crying because I was willing to give a used TH400 to someone for the cost of shipping because used transmissions don't work. But don't tell him that, not that an entire industry exists for used automotive parts.

 

[cucvrus]

No That is laughing at someone that thinks 30 year old used transmissions are worth installing. I have several used CUCV transmissions and would not even consider selling them as useable even when I knew they came from low mileage CUCV's 20+ years ago. Just not worth the effort. I have been in the used parts business all my life. Transmissions are the part that gets returned most often and second is engines. So I am cautious every time. I am not trying to be create an issue I am trying to prevent a lot of extra work for some unknowing person. Doing things half fast is how some people do things right. I seen the stuff they drive. If that is what you like go for it. Spend the time and money up front and do it right the first time. Enjoy Life and Have a Great Day. No crying here.

 

[Skinny]

That is because you think everyone else's expectations are the same as yours. You never think maybe people don't have money to do a full rebuild or maybe they want to tinker and see if they can get something working. Not everything hits the road after being reman'd and has to deliver a million trouble free miles. Just because your used junk doesn't work doesn't mean the thousand of used transmissions being sold are all junk.

You are the one recommending to someone to do a full rebuild and they haven't even answered back if the fluid level is correct. Before jumping into it because you are trying to burn someone with childish comments, why not help someone run through the troubleshooting before spending their money for them?

Enjoy your own life and don't worry about what I do with my day chief...

 

[nyoffroad]

Enjoy your own life and don't worry about what I do with my day chief...

Excuse me, but isn't this the pot calling the kettle black?
I read the posts, the OP asked for thought/opinions and he got them. BTW I agree a low mileage tranny sitting on a shelf for 30 years would be suspect. I learned that the hard way but YMMV.

 

[MarcusOReallyus]

Chill, folks. This isn't about whether a used transmission is a wise choice.

This is about a leaking transmission that might just need to have the fluid topped off, at this point. All transmission problem troubleshooting should start with the most basic check - is there enough fluid?

We don't know that yet. That's first.


CivilEGR, please check that and get back to us.



Comments about magic fluids to the contrary, I have saved a few automotive repairs with AT-205. Success has run the gamut from, "Wow! That solved my problem completely!" to, "Well, at least it's not as bad." to, "That was useless."

I think the difference depends on the composition of the seal and maybe the reason for the failure. A scratched metal surface that chews up a seal just isn't going to be repaired by a magic fluid. On the other hand, a dried up seal CAN be rejuvenated and become good enough.

I've seen it completely fix a power steering leak, slow waaaay down a gusher of a front main sea (that bought me a year!), and noticeably slow down a transmission leak. I've also seen it do diddly squat. Eh.

It might be worth a shot.

 

[Skinny]

Nobody said anything about a transmission sitting on a shelf for 30 years. Try again. And leave my coffee pot out of your rebuttle. It did nothing to offend you.

 

[MarcusOReallyus]

And leave my coffee pot out of your rebuttle. It did nothing to offend you.

Oh, I dunno about that. If it's a typical shop coffee pot, it's pretty close to being declared a SuperFund clean up site.

 

[Skinny]

I had to look up SuperFund, didn't know what it is. Now that I do, I'd declare my shop bathroom over the coffee pot any day of the week

 

[CivilEGR]

It's a little puzzling at the moment. I put almost a gallon of fluid in and the line on the dipstick barely moved. If I try to drive it cold, it doesn't want to grab reverse, but if I let it warm up and idle for 15 minutes, it will grab and go in reverse.

 

[MarcusOReallyus]

Where on the dipstick is it?

 

[cucvrus]

It's a little puzzling at the moment. I put almost a gallon of fluid in and the line on the dipstick barely moved. If I try to drive it cold, it doesn't want to grab reverse, but if I let it warm up and idle for 15 minutes, it will grab and go in reverse.

Internal seals and valves are worn. I had this happen several times with the TH400 in CUCV's. On this note I want to share a bit of sad news. The friend that rebuilt my transmissions the past 25 years has passed away yesterday from the virus. He was in good health, non-smoker, never sickly. I was shocked and still am in shock. This virus has hit home now. Take Care and think about this stuff. It is Real.

 

[ezgn]

I would pull the pan and check to make sure your pick up tube inside the pan is seated correctly and the bolt holding the filter is tight and secure. Make sure the seal on the pickup tube is on correctly. Pouring fluid into your transmission and not having it register sounds like your very low on fluid. Keep adding until you register on your stick.

 

[ezgn]

Internal seals and valves are worn. I had this happen several times with the TH400 in CUCV's. On this note I want to share a bit of sad news. The friend that rebuilt my transmissions the past 25 years has passed away yesterday from the virus. He was in good health, non-smoker, never sickly. I was shocked and still am in shock. This virus has hit home now. Take Care and think about this stuff. It is Real.

I am very sorry to hear about the loss of your friend.

 

[SomeNewGuy]

Im with ezgn, pull the pan and check that tube. When I got mine it was having similar issues and the pickup wasnt seated proper. That caused foaming an low pressure.

Im sure you know this, but just in case you dont.
When you add fluid start up the truck and move through the gears but dont drive around. I move through each for 3 seconds then back through each to park for 3 seconds before double checking fluid level. You can leave the engine running when you add fluid.

Best of luck buddy, report back.

Edit: Also, I think that transmission needs 19 pints of fluid. This includes the TC so if you are REALLY low you may need several gallons as its 8 pints to a gallon so hair over two gallons all together. She is one thirsty girl.

Check the magnet that should be in the bottom of the pan too. If you were running that low on your fluid you may have damaged the guts. A fine soft powder is generally OK an no need to worry but if you have chunks in there you might wanna investigate further... might as well replace the filter while you are in there. I replaced mine about a month ago and the new pickup + gasket + filter kit was like $15 if I remember right.

 

[CivilEGR]

It's still leaking after adding more fluid, so a seal must have either dried out or given out. I'm not outfitted to drop a transmission and replace seals, so this will likely go in to a professional. For the time being I'm going to add some stop leak/seal conditioner and hope is slows the leak. I was getting close to putting it up on jack stands for the winter anyways to keep the tires from getting flat spots, so this might have to wait till next spring.


Side question, as I got reading into the issue more. Multiple places reccomend letting the engine warm up before taking a reading or trying to shift gears. There isn't any connection between the engine and transmission that would transfer heat from one to the other though? If the trucks just idling, the torque converter hasn't locked up, so nothing is spinning in the transmission, including the transmission oil pump? So how does letting the engine warm up change things?