Hey Allisonman !

The PO on my unit installed a very nice digital temp gauge for my transmission. I have a 1995 Airstream Land Yacht 33 - Chevy 454 TBI on a P-30. I don't know what model Allison I have, other then it has overdrive. My mechanic told me it was a Allison ??? turbo. I don't remember the number he gave.

Anyway - perhaps you can answer this without knowing the exact model - What temp should it run? What temp range should I expect, and at what temp should I pull over and kill it. The fancy gauge does me no good if I don't know what I'm watching for.


Re: Hey Allisonman !

Your best bet is to get underneath the unit and read the tag on the transmission. A 1995 Chevy 454 on a P30 chassis is most likely a Hydra-Matic 4L80E transmission, not an Allison. Allison doesn't use the designation turbo. In 1995, Allison didn't make a transmission that had overdrive small enough to go behind the 454.
Re: Hey Allisonman !

In an effort to disprove you, I crawled under the unit last night to get the Allison model number.

Well to my surprise, there it was on the side - Turbo HydraMatic. OK, so forget what I've been told by two mechanics now... I know where NOT to go for transmission work :)

You have any idea what temps I should be running, and what max temp should concern me?

Re: Hey Allisonman !

You're not alone. Lots of people throw around the name Allison to customers and don't know what they are talking about. I've even heard Ford dealers claim Allison helped Ford engineer some components in the Ford 5-spd automatic when they are selling against the 1000 series Allison in the HD pickup trucks. Let's just say I'm close enough with Allison to know that kind of stuff is garbage.

To determine what trans temp is OK, one thing you need to know is where the transmission temperature is being read from. Allison recommended for years that when using a trans temp gauge, the sender be placed in the "to cooler" line. That's the line where the oil is going from the transmission to the cooler. That's the hottest point in the system. Normal trans temperature is 250 deg F and below. Most run less than 180 deg F. The hotter it runs, the shorter the trans fluid life. Once Dexron gets to 300 deg F, it breaks down VERY quickly.

If the temp is being read anywhere after the oil passes through the cooler, add 15 - 20 degrees or so to the temp displayed to safely compensate and get to the max temp the oil may be seeing.

The absolute best automatic transmission fluid you can buy is Allison TranSynd, or any fluid that is physically labeled "TES295". Don't listen to what any sales person says about another fluid being "engineered to be equivalent", etc. If it isn't labeled "TES295", it hasn't passed the test to prove it is able to meet transmission engineering specification #295. I believe there are only three or four fluids that are labeled "TES295".
Re: Hey Allisonman !

I reread my post and realized I may not not been clear. Even though the transmission you have is a Hydra-matic, the temps I shared with you still apply. It's good you have the trans temp gauge. Monitoring the temperature is one small thing you can do to prolong the life of your transmission. In a vehicle that large, sometimes the ole tranny takes a beatin.