Tb45 auto problems

[WALLSHURT]

Had 1998 tb45 auto for 9yrs been brilliant. Now when sitting at 100kph and come completely off throttle the revs drop right down to idle and now have to use 100% braking to slow down. Whats going on? Also wont upshift until at least 3000rpm when driving away??

[growler2058]

G’day welcome aboard

[04OFF]

Welcome on board.


Have you checked the level, colour and condition of the Trans fluid ?

Hate to say it , but if the box has done well over 200k, there a fair chance it may need a rebuild, mine needed a rebuild at 220 ish, but did not play up as bad as you describe yours does, the auto shop said it was very common for those boxes to need major love at that sort of ks.

[mudnut]

Welcome to the forum. Hopefully a fluid and filter change might fix the problem.

[jff45]

At 100 km/h you'd be in O/D so dropping to idle when you release the throttle is normal behaviour. If you want engine braking, just hit the button on the shift lever to switch off O/D.

Your late changing issue would probably be the TPS (Throttle Position Sensor). It's located on the throttle body. The auto will have 2 x 3 pin plugs, 1 grey, 1 brown.

The box should last on average around 250k kms if serviced (and driven) correctly. I've just dismantled one here in my shed that had 326k on it and was just starting to slip but it had been behind an LS1 for a little while. Major wear and play in the clutches but nothing burnt or unserviceable.

[WALLSHURT]

Thx everyone. Strange it all come on like this after I serviced it. I replaced oil and filter with penrite oil. Free wheels when out of O/Drive aswell. Was intermittent at first. Will check TPS switching first.
This tranny has been brilliant in the past. Been towing 5 tonne trailer around the country for years.
Mal

[WALLSHURT]

By the way, I never use o/d when towing.

[WALLSHURT]

Thx Growler

[WALLSHURT]

Thx 04off mmmm

[WALLSHURT]

Thx 04off . Have ordered new auto tps

[WALLSHURT]

Thx mudnut

[WALLSHURT]

Thanks John; it's a miracle. Have changed TPS and all back to normal. With O/Drive off I now have engine braking and engine braking with O/Drive on. Gears now shifting perfectly, like a brand new transmission. This box has done 346,548kms.
Thanks John for your wisdom.
Mal

[WALLSHURT]

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