92 Bighorn 2.8td Auto OVERIDE??

[MacGyver]

Hi All,

I am in the midst of purchasing a 92 Bighorn 2.8 TD, and it come with intermittent overdrive.

I have heard rumours that the gearbox can be manually controlled in a Tiptronic fashion. I would
very much like to achieve this some how so that I can get manual spec fuel economy and eradicate the fault.

Any help would be very much appreciated!

[geeves]

If the ecu fails it does go into a limp home manual select mode. Its not really like tiptronic and it doesnt activate the manual lock up in the auto so will not give improved economy.
92 must be one of the last 2.8s Can you confirm the chassis no starts UBS55...........
By intermitant overdrive do you mean that at 100kph or more its dropping in and out constantly or only when you accelerate firmly?
The second option is normal The first could be the speed sensor (speedo does funny things as well) or something serious

[MacGyver]

If the ecu fails it does go into a limp home manual select mode. Its not really like tiptronic and it doesnt activate the manual lock up in the auto so will not give improved economy.'

Thanks for your swift reply - Could you please tell me more about the 'Manual Lock Up'. Is there a way to activate it?

92 must be one of the last 2.8s Can you confirm the chassis no starts UBS55...........

The truck is miles away from me, but I have emailed the owner and hope he will oblige with a confirmation.

By intermitant overdrive do you mean that at 100kph or more its dropping in and out constantly or only when you accelerate firmly?

That I do not know as I have yet to drive it. I would assume it would be to do with the limiter at 100kph? I am told 'since a jet wash, sometimes it works and
sometimes it doesn't'

The second option is normal The first could be the speed sensor (speedo does funny things as well) or something serious

I have been told about the speed sensors. Is there any hack or workaround or is it obligatory to replace?

Many thanks in advance

[geeves]

to be honest I would want a mechanics report before touching that car. Manual mode will not help.Its just a way to get home and if the box is slipping it wont work anyway. A rebuild of the auto will cost you more than your paying for the car and is probably questionable as to wether its ecconiomic to do.

[MacGyver]

Hi Alan,

I understand your reasoning. I do have some magic up my sleeve, and I don't anticipate holding anybody else responsible if I bought a scrapper based on their advice. I am just trying to get as much information
together before the test drive and potential parting with (a very small amount of) cash.

If you could fill in the blanks it would indeed be very much appreciated.

Best regards to you!

[geeves]

A test drive will tell you so much that you cant tell us yet but as its a fair way from home you need to make a discussion on the spot
When you drive it do the following
Engine cold check the fluid level on a flat surface by starting engine then while parked moving the selector through each gear and holding about 10 seconds then place in park. Each change from forward to reverse should activate in 1 to 2 seconds. Fluid should be at the lower mark on the dipstick and a clear bright red. It may be a straw colour if old which is ok but due for replacement. (if jet wash is what I think it is then it a straw colour indicates an untruth) Dark brown or red is bad Smelling like burnt toast is bad. Sparkles in the fluid is very bad.
Take it for a 20km drive These gearboxes do feel a bit sloppy in changes compared to modern ones but you should feel good up and down shifts and the converter should lock in the top 2 gears above 70kph but drop out in hard acceleration.
Dropping down the gears manually should achieve good engine braking
After drive recheck fluid as above it should be at the top mark
I dont know what you are paying for this wagon but I recently sold an 89 bighorn (manual) to a wrecker that specialises in sending parts overseas. $1220NZ Your closer to the countrys the parts go to so Im surprised if you dont have similar buyers there. Thats about 700 pounds