Transmission Acting Dumb

[mcfixstuff]

No issues with my transmission for the last 2 years. I replaced the vacuum governor a year ago, and have had no issues. Recently, my truck has hated going 35mph. When I am driving 35mph, the transmission is trying with all its might to figure out what gear it wants to go into. 3.73 gearing if anyone asks. The transmission sometimes bounces between 3rd and 4th, and sometimes tries to drop into overdrive which will be about 900 rpm at that speed. Once it realizes it cant do O/D it pops back out. This makes the driving experience at 35mph extremely unpleasant as the car constantly jerks around while trying to find the gear. Putting it on D and not OD helps the issue a bit, but the rpm needle still bounces a little at that speed. No slippage during full throttle take offs, once I get below 30 or above 40, everything is perfectly fine. Is this a synchro? Do I need to adjust the governor? Do I need to change the worm gear to compensate for my 31" tires? What should I have for dinner tonight? Anyone else have this issuse?

Any help would be appreciated! I really don't wanna drop the transmission quite yet. It looks like it had already been done before I got it since the mounting bolts were loose and it was leaking fluid when I got it 2 years ago. The fluid has been changed twice since I got it. Every 12k miles I do it.

 

[Rick]

It could be that the vacuum modulator is bad again. Pull the rubber hose and check for fluid. There shouldn't be any. If that's not it the governor could be stuck.

 

[mcfixstuff]

It could be that the vacuum modulator is bad again. Pull the rubber hose and check for fluid. There shouldn't be any. If that's not it the governor could be stuck.

No fluid in the hose. One thing I should mention is that it has bigger tires, and I just ordered the proper speedo gear to compensate for the bigger tires.
Is the A4LD picky with its transmission fluid? I use Valvoline Max Life. It says it's supposed to work with Mercon.
Also, I read on some other forums people talking about adjusting the bands and adjusting other transmission parts... is that something relatively easy, or do I have to pull the transmission? Do I need special tools? They talk about it like it's something you gotta do every so often.
I'm gonna be honest, automatic transmissions are somewhat foreign to me.

 

[~X~]

Have you checked fluid level?

 

[mcfixstuff]

Yes I did. I read on some other forums that the 3-4 shift solenoid is a common problem on those transmissions. While doing my last transmission fluid change, I noticed one of the shift solenoids having their plastic back lose and not securely attached to the metal housing. Problem is, I know once I take the valve body off, I'll want to replace the gasket, and I cant find anyone who sells just the valve body gasket. They wanna sell a whole kit that's over $50.

 

[~X~]

Seems like it's worth looking at the solenoids then. I've been buying parts from Transmission parts USA. I just did a search there:

A4LD transmission valve body gaskets A4LD transmission gaskets

A4LD transmission valve body gaskets A4LD transmission kit with valve body gaskets A4LD transmission valve body skift kit ATSG transmission repair manuals

www.transmissionpartsusa.com