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ColinWB 09-23-2012 11:36 AM

overheating transmission. why ? what to do?
Hi. I do not understand why I'm getting TOH light coming on together with the 'O/D Off' on my AUTO change Jeep GC WJ.

Three years ago I replaced the thermostatic fan clutch so I reckon it's not that, also had a recent new rad thermostat. Transmission fluid appears clean and if anything over full (when cold, the fluid level is at the full/hot mark). Temp guage shows well below boiling point (100 degs C [I'm in Spain]) , slightly lower since fitting a new water pump (the other one was weeping and slowly losing coolant)

After driving at say 70-80 mph for a short while the warning lights come on and O/D disengages so the engine revs alarmingly...... sometimes for just a moment sometimes for a minute or two. Took the car for a long drive y'day and kept it below 60 mph without any problems. But today I went up into some mountains and kept in second without problems. After a long walk and time for the car to cool, when coming down the tracks with the engine obviously doing very little work, the lights came on. Why? It doesn't make sense.

I do not know when the fluid was changed last but the engineer who just repalced the water pump said it was OK.

The car is a WJ variant 8L4B. 5 cylinder dieasel 3124 cc. Engine is (unhappily) the Italian VM - type DVM73B. (I understand the Spanish Jeeps have the Italian engine as it's cheaper than the Chrysler built one !!!!)
Any help will be appreciated. I look forward to hearing from you.

Frango100 09-23-2012 03:49 PM

Re: overheating transmission. why ? what to do?
Don't know which transmission is installed on your jeep, but when the level shows full/hot when cold, that is already not good. A too full transmission will form foaming of the fluid and that can cause all kind of strange behaviour. I would start by draining some fluid until its at the right level and see what it does.

ColinWB 10-08-2012 07:40 AM

Re: overheating transmission. why ? what to do?
Thanks, good point. Will get it looked at again.

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