Retarder Settings/Allison Transmission

[0533]

While I was at Prevost Car in Jacksonville last week I mentioned to John Kincaid the service manager that when I am running down the road or worse running down long grades and take my foot off of the gas pedal I do not feel the full affects of the engine retarder in either position one or two until I am below certain speeds but certainly not at highway speeds in six gear.

John said that my Allison was set at a factory default setting for six gear and that he would make the change in a few minutes with his computer. He did it in about 5 minutes time and set the default to 4th gear, what a difference now.

When I take my foot off the gas it actually does something and really helps me stay off the brake pedal in occasions when our friendly truckers (not picking on Truckers all future Nascar drivers qualify) decide to turn their rigs into NASCAR's and pull out from nowhere to get around slower cars in their lanes.

What I like most is that I can either allow the full force of the retarder to kick in, use the 1st setting or simply turn it off. I cannot wait until I get out West as I was finding myself using too much braking action to get the bus down to speeds where the retarder could actually work efficiently.

I am sure this is old news for you pros but it was a cheap date for me and a great solution to a old problem.

[Jon Wehrenberg]

There are no free lunches. Heat is the enemy of all things mechanical.

Monitor the transmission temp and do your best to keep it as cool as possible. At best that extra heat developed by the retarder is just cooking your fluid (which is why just the simple fact that towing a car is treated by Allison in the maintenance shedule as severe duty and cuts the maintenance interval time in half).

The faster you slow down using the retarder only the greater the temperature developed. Mine drops a single gear which is excellent and on steeper declines I manage temps by selecting speeds and gear manually, along with retarder selector switch settings. My target maximum temp is 230. For no other reason than I am anal.

[0533]

I had been warned about this as well. My plan is to use the 2nd detent setting in heavy close in traffic at highway speeds or when descending steep grades put otherwise use the 1st setting or turn it off as I do in towns and neighborhood driving to avoid noise.

I did change my transmission fluid and filters over to Transynd last week and have seen a noticeable difference in temps already.

I also replaced my Detroit with synthetic oil and have seen a drop in engine temps. Prevost said it was best to wait until I had at least 40K on the engine before changing over to synthetic.

[Gary & Peggy Stevens]

Bruce, does your Marathon have an actual Transmission Retarder or a Jake Brake?

The way you were mentioning you could use stage 1 or stage 2 it sounded like you were talking about what I have which is a Jake Brake.

I am not real happy about how my Jake is functioning either, so I was hoping it would be just a computer hook up to adjust it, BUT PROBABLY NOT that simple for me?

MY BUS IS STILL IN PREVOST, but they tell me maybe I can get her in a week or more?

Gary S.

[0533]

I call everything by my own naming conventions barely know what I am talking about, i guess it is a 2 stage Jake Brake, and it is 5 minute change with the computer from default 6th gear to 4th gear, Jon set his at 5th I think he said, but I really like my setting at least for now in 4th, and can adjust the amount of braking action with the first or second detent on the toggle switch or non at all.

[Gary & Peggy Stevens]

I call everything by my own naming conventions barely know what I am talking about, i guess it is a 2 stage Jake Brake, and it is 5 minute change with the computer from default 6th gear to 4th gear, Jon set his at 5th I think he said, but I really like my setting at least for now in 4th, and can adjust the amount of braking action with the first or second detent on the toggle switch or non at all.

Bruce, I wanted clarification in your terms, because apparently you and I have the Jake Brake, and Jon in his Liberty has the Transmission Retarder, which is a completely separate braking system. We have talked about the differences in them numerous times on this board.

I do hope I can also get the increased stopping power with my Jake brake with a mere computer adjustment, like you got?

Gary S.

[Jon Wehrenberg]

If it is a Jake don't worry about transmission temps. There is no downside to a jake mechanically.

However, unless gearing is different from bus to bus my transmission will not drop into 4th above 55 which is at the rev limits for the engine. Setting it up for fourth may only allow it to drop to 5th until the bus slows to 55.

[0533]

I'll check that out on the next ride. I ran mostly on cruise control on 95 on the way back from Prevost at about 72 mph 1850 RPM . I did however notice that when I was going over overpasses coming down the inclines on the other side I could feel the braking action on the cruise control better than before, does the jake play any role in this process??

[Jon Wehrenberg]

I'm with Gary and don't know if you have a retarder or Jake.

You mention Allison in the first post, but talk about turning it off to avoid noise, a characteristic of a jake. You are talking about 2 completely different types of engine or transmission braking.

I am further confused because I was unaware a jake would engage when using a cruise control, but i know a retarder will engage. If you have a retarder (small stick with six or seven positions on the right side of the steering column opposite of the turn signal) and a rocker switch to engage it, along with an amber lighton the dash to indicate it is functioning then I at least understand what you have. You will not drop into forth at 72 miles per hour.

On my jake equipped bus downshifts had to be done manually to keep the revs up so the jake would work efficiently. Its effect was minimal at lower revs, but it was very effective at the higher RPMs.

[0533]

Well I guess i need to spend some time at the bus with the documents. I feel based on what you have said that I have a Jake Brake. I do however have a rocker switch on the panel in aft of the Allison shift pad at the drivers window. I certainly have no small stick with six or seven positions on the right side of the steering column opposite of the turn signal, but you sure have me wondering about what you are saying. I am pretty sure its a jake as it is a Prevost item that was original equipment. It does not offer much resistance at slower speeds your right, but with the computer gear change it works much better at highway speeds.