Transmission Hanging in 3rd Occasionally

[JohnTN]

1995 Q45 with 136K original miles, 3rd owner since 77K. Transmission leak on top of case was repaired at 77K in 2001, no fluid changes since then. Fluid is at full and pink with no smell. Car has been driven moderately with no brake stands or other mistreatment.

Maintenance has been changing the engine oil and filter myself every 4-5K miles. Didn't realize the transmission needed annual maintenance.

Have had no problems with car since purchase, but in the last month it has occasiionally (maybe 5-6 times) stayed in third gear after accelerating onto interstate up to 60 mph at part throttle. If I let off accelerator for a second and coast it will shift up.

Another symptom is that 2 or 3 times under light throttle it has shifted into 4th with a hard jolt -- almost like the lockup was engaged when it shifted.

And I noticed today that if I back off the throttle and coast at any speed above 50 mph the lockup doesn't disengage -- I thought it used to disengage when throttle was released. As it coasts down below 50 it does disengage.

I will try a BG flush if you think it might help, but not sure I would pay to put in a reman transmission.

Have not taken it to the dealer yet, can they do a computer diagnosis?

Any suggestions?

John

[Q45denver]

Check for loose or damaged vacuum hoses.

[texasoil]

First have the transmission power flushed (a complete oil change with the engine running. Unless you check the fluid using white blotter paper, you will not see the build-up of varnish untill there is a lot of it. After the flush and with clean fluid, add a can of SEAFOAM transmission varnish remover and drive 20-50 miles to see if improved or not. If improved, add another can and drive a couple of weeks, then powerflush again. Be sure and also replace the external oil filter (between the battery and front of engine. Ford has an all metal transmission line filter (normally used when replacing transmissions) that is very low cost (<$20) and is a better unit than the Infiniti OEM. The internal 'filter' in the transmission is a fine metal screen and can get clogged with varnish-which the SEAFOAM will remove. Most likely, a small amount of varnish has accumulated in the electronically controlled solenoid valves inside the transmission case. You can remove the pan and then the valve body if necessary.sticking transmission