Jeep 4.0 Automatic not changing gears.

[Gradinen]

Hello! 

I have an 88 automatic Laredo that has been sitting for about 20 years... I've just got it going again with the aid of the forum and such. 

I started to change the oils to check the status of the viechle, engine, trans and gearbox. 
Thing is, the gearbox won't change gears when I'm driving.

 

The gearbox doesn't change gears until I've reached about 60kmh, I let go of the throttle and it changes back into first gear at about 55kmh. 
I've tried to change gears manually by changing from 1-2 to 3 but nothing, doesn't matter at what speed I'm driving. 

I've checked the Kickdown wire. It doesn't look like its broken, its springy when I pull it and doesn't seem loose. Though, when I try to do the adjustment reset as many show in the videos on youtube, I move it all the way back and push the throttle. The kickdownharnessthing only changes a little bit with a click. The videos show a greater change then what happens to mine. 

What I recently did with the gearbox? Well, I took the pan down and changed the filter and the oil. There were not a single metal shaving on the magnets. 
I did a quick testrun when I first got the car going, and before I changed the oils.. I can recall that it changed between gears but brainghosts makes myself doubt myself a wee bit. I only drove about 20-30 kmh as I had my toddler with me in the car. 

As any amature I've consulted with AI and gotten the advice to either change the oil again, do some accelarations and hope it fixes itself, or its the govenor in the gearbox. Suggesting I remove it and clean it as dirt might have gotten into it. 

What do you pro comanche folks say? Anyone else had the same problem, or have a guess what might be behind the issue? 
Its a 3 gear gearbox on a 4.0 6 cylinder laredo. 

[89 MJ]

A 3 speed with a 4.0 you say? Does is the transmission computer controlled or is it just kickdown linkage? What type of transmission is it?

 

I don't think that you are from the US, but here in the US, all 4.0 Comanches with an automatic transmission came with the AW4 4 speed automatic. Other AMC and Jeep models could come with 3 speed autos. In AMCs, I know this was the TF998 in the late 70s. 

[Gradinen]

1 hour ago, 89 MJ said:

From what I can tell its only Kickdown linkaged, any way of telling its computer controlled? 
No, I'm from Sweden and was surprised myself that it was a 3 speed Laredo with the 4.0. 

 

[89 MJ]

Your English is very good. When you say the kickdown wire, it is just a metal cable inside a plastic sleeve, correct? Any chance you can take some pictures of what you're working with?

[fiatslug87]

Are you sure the fluid is at the correct level? Mine does that once in a while, I add a little fluid and then it shifts properly.

 

Please add your truck to the registry, your build sheet will be provided and trans identified. https://comancheclub.com/forum/31-1988/

[Gradinen]

1 hour ago, fiatslug87 said:

Are you sure the fluid is at the correct level? Mine does that once in a while, I add a little fluid and then it shifts properly.

 

Please add your truck to the registry, your build sheet will be provided and trans identified. https://comancheclub.com/forum/31-1988/

Yes, I thought that was the issue at first. 
I rechecked everything this evening. I drove the car, made the trans warm and parked it on a level surface, I filled from about just at the minimum mark on the stick to about right in the middle. No change at all. Perhaps there's a slight more noticable "clunk" when I put it into drive. 

[Gradinen]

1 hour ago, 89 MJ said:

Your English is very good. When you say the kickdown wire, it is just a metal cable inside a plastic sleeve, correct? Any chance you can take some pictures of what you're working with?

Thanks, the younger generation (90s) are pretty much forced to speak english in every day life if you're in the right trade. 

Yes, its just a metal wire in a plastic sleeve. I can fix a picture tomorrow! Thanks. 

[89 MJ]

32 minutes ago, Gradinen said:

Thanks, the younger generation (90s) are pretty much forced to speak english in every day life if you're in the right trade. 

Yes, its just a metal wire in a plastic sleeve. I can fix a picture tomorrow! Thanks. 

Perfect! I think we should also try to figure out what transmission it has. The Chrysler transmissions (like the TF998 that I suspect you may have) do not run the pump in park, so the fluid level must be checked with the engine running and in neutral.