auto transmission gear problem, won't shift up gear

[Guest putputcar]

Hi all,

It won't shift up after 20 miles of driving in hot weather, I will be going 20mph on 5000rpm and the car is not going anywhere.

 

It seems like only happens when the weather is hot, texas hot.

I have checked the fluild level and it has fresh pinkish transmission fluid in it.

I always thought it was the fluid temperature got too hot so it switches to safe mode.

Apparently that's not the case anymore.

I just put in another cooler and fan yesterday and it happened again on my 1st test drive after 20miles of driving.

 

I have,

- 2 transmission coolers with fans (dual core, 14" x 10", spal fan)

one is underneath the headlight with direct air flow, and the second one is between front mount intercooler and radiator.

- fluid temp is 144F-148F when it happened

- 3800 stall converter

- it was 90F outside

- after driving about 20 miles

- front bumper was off during the test drive.

- code 71 (believe is EGR)

 

Could it be the stock transmission fluid temperature switch is bad?

Edited June 22, 2008 by putputcar (see edit history)

[tDR]

Sounds pretty much like a knackered autobox - one of mine did that so I ended up swapping it out for a BL box to try and end my autobox woes.

 

Likely worn clutch bands inside it or a busted sprag. Is it always the same gear it's in when it does it? Can you try shifting manually and skip past the gear where it's happening? Will help determine the failure.

 

What kinda autobox is it and how many miles old is it?

 

Cheers,

 

Brian.

[Guest putputcar]

The manual shifting won't help pass the gear and it has about 116000 miles on it.